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Environmental Engineering and Management Journal, November/December 2007, Vol.6, No.6, 479-608 

http://omicron.ch.tuiasi.ro/EEMJ/ 


____________________________________________________________________________________________ 

CONTENTS 

____________________________________________________________________________________________ 

Phenol degradation in water through a heterogeneous photo-Fenton process 

Beatrice Iurascu, Ilie Siminiceanu, Miguel Vincente…………………………………………………… 479 

Study concerning the influence of oxidizing agents on heterogeneous photocatalytic 

degradation of persistent organic pollutants 

Anca Florentina Caliman, Camelia Betianu, Brindusa Mihaela Robu, 

Maria Gavrilescu, Ioannis Poulios………………………………………………………………………… 483 

Nonmarket valuation of Acequias: stakeholder analysis 

Steven Archambault, Joseph Ulibarri……………………………………………………………………. 491 

Metals concentration in soils adjacent to waste deposits 

Camelia Drăghici, Elisabeta Chirilă, Narcisa Elena Ilie……………………………………………..... 497 

Polyelectrolyte – surfactant complexes 

Mihaela Mihai, Gabriel Dabija, Cristina Costache…………………………………………………...... 505 

Modelling of sorption equilibrium of Cr(VI) on isomorphic substituted 

Mg/Zn-Al – type hydrotalcites 

Laura Cocheci, Aurel Iovi, Rodica Pode, Eveline Popovici………………………………………......... 511 

Virtual environmental measurement center based on remote instrumentation 

Marius Branzila, Carmen Alexandru, Codrin Donciu, Alexandru Trandabăţ, 

Cristina Schreiner……………………………………………………………………………………….. 517 

Microwave-assisted chemistry. A review of environmental applications 

Mioara Surpăţeanu, Carmen Zaharia, Georgiana G. Surpăţeanu…………………………………. 521 

Environmental pollution with VOCs and possibilities for emission treatment 

Liliana Lazăr, Ion Balasanian, Florin Bandrabur………………………………………………………. 529 

Sustainable irrigation based on intelligent optimization of nutrients applications 

Codrin Donciu, Marinel Temneanu, Marius Brînzilă………………………………….………………... 

537

Obtaining and characterization of Romanian zeolite supporting silver ions 

Corina Orha, Florica Manea, Cornelia Ratiu, Georgeta Burtica, Aurel Iovi………….…………… 

541 

Using GPS technology and distributed measurement system 

for air quality maping of rezidential area 

Alexandru Trandabăţ, Marius Branzila, Codrin Donciu, Marius Pîslaru, 

Romeo Cristian Ciobanu…………………………………………………………………………… 545 

Synthesis, characterization and catalytic reduction of NO x emissions over LaMNO 3 perovskite 

Liliana-Mihaela Chirilă, Helmut Papp, Wladimir Suprun, Ion Balasanian………………………….. 549 

Kinetics of carbon dioxide absorption into aqueous solutions of 1, 5, 8, 12- tetraazadodecane (apeda) 

Ilie Siminiceanu, Ramona-Elena Tataru-Farmus, Chakib Bouallou………………………………… 555 

Urban traffic pollution reduction using an intelligent video semaphoring system 

Codrin Donciu, Marinel Temneanu, Marius Brînzilă…………………………………………………. 563 

Study of increasing soil fertility into a site with high electric field around 

using polymeric conditioning agent 

Ioan Ivanov Dospinescu , Carmen Zaharia, Matei Macoveanu………………………………………... 567 

Methods and procedures for environmental risk assessment 

Brînduşa Mihaela Robu, Florentina Anca Căliman, Camelia Beţianu, 

Maria Gavrilescu……………………………………………………………………................................... 573 

Comparative study of some essential elements in different types of vegetables and fruits 

Alina Soceanu, Simona Dobrinas, Viorica Popescu, Semaghiul Birghila, 

Vasile Magearu ................................................................................................................................ 593 

Chemical reactor design and control 

Book review……………………………………………………………………………………………………. 597 

Modeling of process intensification 

Book review……………………………………………………………………………………………………. 601 

Ullmann’s - Modeling and simulation 

Book review………………………………………………………………………………………… 603 

Micro Instrumentation - For high throughput experimentation and 

process intensification – a tool for PAT 

Book review……………………………………………………………………………………………………. 605

Environmental Engineering and Management Journal November/December 2007, Vol.6, No.6, 479-482 



______________________________________________________________________________________________ 

PHENOL DEGRADATION IN WATER THROUGH A HETEROGENEOUS 

PHOTO-FENTON PROCESS 

Beatrice Iurascu 1 , Ilie Siminiceanu 1∗ , Miguel Vincente 2 

“Gh. Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Engineering Inorganic Substances, 

71A D.Mangeron Bd., 700050 - Iasi, Romania 

2 University of Salamanca, Department of Inorganic Chemistry, Spain 

Abstract 

A new photo-Fenton catalyst has been manufactured from synthetic layered clay laponite (Laponite RD) by the pillaring 

technique Eight different catalyst samples were prepared: four without thermal aging (WTA) calcined at 523 0 K, 623 0 K, 723 0 K 

and 823 0 K, and other four with thermal aging (TA) calcined at the same temperatures. The activity of the TA- 623 sample was 

evaluated in the phenol degradation by the photo- Fenton process. The influence of five important operating factors has been 

studied experimentally: the wavelength of the light source (UV-C and UV-A); catalyst dose( 0 to 2 g/L), initial phenol 

concentration ( 0.5 to 1.5 mM), hydrogen peroxide initial concentration ( 20 to 100 mM) and th initial solution pH (2.5 to 3.5 ) at 

303 K.The results have shown that the almost complete conversion was possible , after only 5 minutes, under the following 

operating conditions: a low pressure mercury lamp as source of UV-C of 254 nm; pH3; a dose of 1 g catalyst/ L, a hydrogen 

peroxide concentration of 50 mM for a solution containing 1mM phenol , at 303 K. 

Key words: phenol degradation, Fe- Lap-RD catalyst, photo- Fenton, kinetic experiments, factor influence 

1. Introduction 

The phenols have become the most abundant 

pollutants in industrial wastewater, due to their wide 

utilization in different industries (Almaizy and 

Akgerman, 2000; He et al., 2005; Kusic et al., 2006). 

Their presence contributes notably to the pollution of 

the effluents due to their high toxicity to aquatic life. 

The LD 50 dose for aquatic organisms, determined on 

Daphnia is 12 mg phenol/L in 48 hours. They also 

may cause carcinogenic and mutagenic effects to 

humans (Kusic et al., 2006). Therefore, the maximum 

concentration of phenol in EU in water is 0.5 µg/L. 

Common commercial wastewater treatment 

methods utilize the combination of the biological, 

physical and chemical treatment (Droste, 1997; 

Gogate and Pandit, 2004a/b).The biological treatment 

units tend to become very large due to the slow 

biological reactions. The physical methods only 

transfer waste components from one phase to another. 

Chemical treatment of phenols, such as chlorination, 

can result in formation of chlorinated phenols and 

their byproducts which have been reported as toxic 

and non biodegradable (Gogate and Pandit, 2004a). 

An attractive alternative for the removal of 

organic contaminants from wastewater are the so 

called advanced oxidation processes (AOPs) which 

generate hydroxyl radicals in sufficient quantities to 

oxidize the majority of the organics present in the 

effluent water (Siminiceanu, 2003). The AOPs used 

in the laboratory studies for phenol degradation have 

been reviewed and compared (Esplugas et al., 2002; 

Gimeno et al., 2005).The photo-Fenton process has 

been found the most effective among the investigated 

AOPs. The high effectiveness of the photo-Fenton 

process is attributed to the formation of hydroxyl 

radicals (HO . ) in the reaction (1), and the regeneration 

of Fe(II) ions by photo- reduction of Fe(III) ions 

(reaction 2): 

Fe 2+ + H 2 O 2 + hν = Fe (OH) 2+ + HO . (1) 

∗ Author to whom all correspondence should be addressed: isiminic@ch.tuiasi.ro

Iurascu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 479-482 

Fe (OH) 2+ + hν = Fe 2+ + HO . (2) 

Despite its effectiveness, the homogeneous 

photo- Fenton process has an important drawback for 

practical application to large water flow rates, caused 

by sludge formation in the final neutralization step 

(Siminiceanu, 2003). Therefore, new heterogeneous 

Fe-based catalysts have been prepared and tested 

(Carriazo et al., 2003; Feng et al., 2006; Iurascu et al., 

2006; Sum et al., 2005; Timofeeva et al., 2005). 

Sum et al. (2005) prepared a new laponite 

clay-based Fe nanocomposite as heterogeneous 

photo- Fenton catalyst, and tested it in the 

mineralization process of an azo- dye Acid Black 1 

(AB 1) in water , in the presence of H 2 O 2 and UV 

light. Under the optimal reaction conditions found by 

the authors (0.1 mM AB1, 6.4 mM H 2 O 2 , 1.0 g 

catalyst/L, pH3, 8W UV-C) they achieved a complete 

discoloration and a 90% mineralization after 90 min 

reaction time, and a complete TOC removal after 4 

cycles of 2h reaction time. These encouraging results 

determined the authors of the present paper to prepare 

a similar catalyst and to test it in process of the 

degradation of phenol in water. 

2. Experimental 

The synthetic laponite clay (laponite RD) was 

supplied by Bresciani S.R.L. and used as starting 

material to prepare a series of Fe-Lap-RD catalysts. 

The laponite RD powder has a specific area of 370 

m 2 /g. The rest of the chemicals employed in the 

experiments were supplied by Merck (H 2 SO 4 98% 

and H 2 O 2 35%), Sigma-Aldrich (Na 2 CO 3, KI, 

KH 2 PO 4 , NaOH, phenol and Fe (NO 3 ) 3 ⋅9H 2 O). The 

water used was of Milli-Q quality. 

A series of Fe-Lap-RD catalysts were prepared 

through a reaction between a solution of iron salt and 

a dispersion of laponite RD clay. Firstly an aqueous 

dispersion of laponite RD clay was prepared by 

adding 2 g laponite RD to 100 mL H 2 O under 

vigorous stirring. Secondly, sodium carbonate was 

added slowly as a powder into a vigorously stirred 0.2 

M solution of iron nitrate such that a molar ratio of 

1:1 for [Na + ]/[Fe 3+ ] was established. The obtained 

solution was added very slowly into the dispersion of 

laponite clay prepared in the first step until a ratio of 

11 mmol Fe 3+ per gram clay was achieved. The 

suspension was stirred 2 h and then divided into two 

portions. One portion was kept in an oven at 373 K 

for two days. For simplicity this portion will be 

referred as “thermally aged” (TA). Another portion, 

referred as “without thermal aging” (WTA) was 

stirred for two days at room temperature to allow 

sufficient intercalation of the clay. After that, the 

precipitate of each portion was collected by 

centrifugation and washed several times with 

deionised water to ensure that all the Na + ions were 

removed. The recoveries were dried at a temperature 

of 373 K for 24 h and further divided into four equal 

portions. The two portions underwent a calcination 

process at different temperatures for 24 h. The 

calcination temperatures were 523, 623, 723, and 823 

K. For simplicity, the clays will be referred as: WTA- 

T for the clays obtained without thermal aging and 

TA-T for the clays prepared by thermal aging; T 

represents the calcination temperature used in this 

study: 523, 623, 723, and 823 K The characterization 

of catalyst samples by chemical analysis, SEM/EDS, 

XRD and DTA was described in a previous paper 

(Iurascu et al., 2006). 

The photocatalytic activity of each pillared 

clay was evaluated in the process of mineralization 

and conversion of a 0.1 mM phenol solution in the 

presence of 5 mM H 2 O 2 , 1 g/L catalyst and UV 

irradiation using a Unilux Philips lamp (15W UV-C, 

λ=254 nm). Irradiation was carried out in 

magnetically stirred, cylindrical Pyrex quartz cell (4 

cm diameter, 2,3 cm height) containing 10 mL 

solution, at room temperature. The pH was adjusted 

to 3 using a H 2 SO 4 solution. This is the optimal pH in 

the homogeneous photo-Fenton process 

(Siminiceanu, 2003). The start of the reaction was 

considered to be the moment when the cell was put 

under the UV-C lamp. After irradiation the catalyst 

was separated from the solution by filtration with 

Hydrophilic PTFE Millex-LCR filter (pore diameter 

0.45x10 -9 m). 

The conversion of phenol was measured using 

a Merck-Hitachi HPLC. The column used was a RP- 

C18 LichroCARP (Merck, length 125 mm, diameter 

4mm) packed with Li-Chrospher 100 RP-18 (5x10 -9 

m diameter). Isocratic elution was performed with a 

30/70 mixture of acetonitrile/aqueous phosphate 

buffer (0.05 M, pH 2.8). The mineralization of phenol 

was measured using a Shimadzu TOC 5000 Analyzer. 

The leaching iron (Fe 3+ and Fe 2+ ) from the catalysts 

was measured using a UVVIS Cary 100 Scan 

spectrophotometer and a Merck reagent Spectroquant. 

The experimental determinations were carried out at a 

wavelength of 565 nm. Because the reaction was still 

going on after the irradiation time was over, it was 

necessary to use a stopping reagent, which contained 

0.1M Na 2 SO 3 , 0,1M KH 2 PO 4 , 0,1M KI and 0,05M 

NaOH. The stopping reagent was injected in the 

sample solution immediately after filtration, using a 

1:1 volumetric ratio. After the selection of the pillared 

clay with the best activity and the smallest quantity of 

leached iron, the influences of several parameters 

over photo-activity such as UV light wavelength, 

initial concentration of phenol, initial concentration of 

H 2 O 2 , initial catalyst dose and initial pH, were 

studied. 

3. Result and discussion 

The results are presented under the form of the 

kinetic curves C Ph versus time, or X Ph versus time. 

The conversion degree of the phenol X Ph has been 

calculated with Eq. (3): 

X Ph = 1- C Ph / C o Ph (3) 

480 4

Phenol degradation in water through a heterogeneous photo-Fenton process 

where C 0 Ph is the initial molar concentration of the 

phenol, and C Ph is the molar concentration of the 

residual phenol at a given time. 

3.1. Influence of the light source 

3.3. Influence of initial phenol concentration in water 

The influence of the initial phenol 

concentration is illustrated in the Fig. 3. 

Fig. 1 presents the influence of the light source 

on the phenol conversion, at different catalyst doses, 

and the other constant factors ( C 0 Ph = 1 mM; C 0 H2O2 = 

50 mM, pH3; T= 303 K). The low pressure mercury 

lamp emitting UV-C of 254 nm was more effective 

than the lamp emitting UV-A. 

Fig.3. Influence of the initial phenol concentration (catalyst 

dose of 1g/L; C 0 H2O2 = 50 mM, pH3; T= 303 K 

3.4. Influence of hydrogen peroxide dose 

Fig.1. Influence of light source (C 0 Ph = 1 mM; C 0 H2O2 = 50 

mM, pH3; T= 303 K) 

Fig. 4 presents sections at constant reaction 

time of the kinetic curves. The results show that for a 

solution with 1mM phenol the optimal dose is of 50 

mM hydrogen peroxide. 

3.2. Influence of the catalyst dose 

Fig. 2 presents the results for different catalyst 

doses with a UV-A lamp of 40 W and the other 

constant factors (C 0 Ph = 1 mM; C 0 H2O2 = 50 mM, pH3; 

T= 303 K). The best results have been obtained with a 

dose of 1g catalyst/ L. 

Fig.4. Influence of the hydrogen peroxide dose at different 

reaction time (C0Ph = 1 mM; catalyst dose of 1g/L, pH3; 

T= 303 K) 

3.5. Influence of pH 

Fig.2. Influence of catalyst dose on the phenol 

conversion. ( C 0 Ph = 1 mM; C 0 H2O2 = 50 mM, pH3; T= 

303 K) 

The results, represented in Fig. 5, have shown 

that the maximal conversion could be obtained with a 

pH between 2.5 and 3.0. This is in accordance with 

previous experimental and theoretical studies on 

homogeneous photo-Fenton process. 

481

Iurascu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 479-482 

Fig.5. Influence of pH on the phenol conversion. 

( C 0 Ph = 1 mM; C 0 H2O2 = 50 mM, catalyst dose of 1g/L; T= 

303 K) 

4. Conclusions 

A new heterogeneous photo-Fenton catalyst 

has been prepared by the intercalation and pillaring of 

a laponite clay with iron salt. Eight different catalyst 

samples were prepared: four without thermal aging 

(WTA) calcined at 523 K, 623 K, 723 K and 823 K, 

and other four with thermal aging (TA) calcined at 

the same temperatures. Catalyst samples thermally 

aged at 623 K have been used to study the influence 

of five factors on the phenol conversion by the photo- 

Fenton process: light source, catalyst dose, initial 

phenol concentration, hydrogen peroxide dose, and 

pH. 

The results could be useful for the selection 

of optimal operating parameters as well as for further 

kinetic interpretation. 

References 

Almaizy R., Akgerman A., (2000), Advanced oxidation of 

phenolic compounds, Adv.Environ. Res, 4, 233- 

244. 

Carriazo J.G., Guelou E., Barrault J., Tatibouet J.M., 

Moreno S., (2003), Catalytic wet peroxide oxidation 

of phenol over Al- Cu or Al- Fe modified clays, 

Appl. Clay Science, 22, 303- 308. 

Droste R.J., (1997), Theory and Practice of Water and 

Wastewater Treatment, John Wiley and Sons, New 

York, 450. 

Esplugas S., Gimenez J., Contreras S., Pascual E., 

Rodriguez M., (2002), Comparison of different 

advanced oxidation processes for phenol 

degradation, Water. Res., 36, 1034- 1042. 

Feng J., Hu X., Yue P.L., (2006), Effect of initial solution 

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Fe nanocomposites as heterogeneous photo- 

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1243. 

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482 4




______________________________________________________________________________________________ 

STUDY CONCERNING THE INFLUENCE OF OXIDIZING AGENTS 

ON HETEROGENEOUS PHOTOCATALYTIC DEGRADATION OF 

PERSISTENT ORGANIC POLLUTANTS 

Anca Florentina Căliman 1∗ , Camelia Beţianu 1 , Brînduşa Mihaela Robu 1 , 

Maria Gavrilescu 1 , Ioannis Poulios 2 

1 “Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering 

and Management, 71 Mangeron Blvd., 700050 - Iasi, Romania 

2 Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Physical Chemistry, 54006 Thessaloniki, 

Greece 

Abstract 

In this paper, the application of the heterogeneous photocatalysis in degradation of a cationic copper phtalocyanine dye, used as 

model of persistent organic compound is investigated by assessing the efficiency of the process. The influence of hydrogen 

peroxide on the photocatalytic process is studied using two types of commercial catalysts, such as TiO 2 Degussa (88% anatase, 

20% rutile) and TiONa Millennium (100% anatase). Another electron acceptor, FeCl 3 is also used for investigation of adsorption 

and photocatalytic degradation efficiencies of the dye on TiO 2 Degussa photocatalyst. The results have shown that Millennium 

photocatalyst and the iron(III) salt exhibit a negative influence upon the studied process. 

Key words: Keywords: heterogeneous photocatalysis, oxidizing agents, persistent organic pollutants 


Heterogeneous photocatalysis was 

intensively studied in the last decade due to the fact 

that it may be applied for degradation of a big number 

and various types of persistent pollutants, resulting in 

complete mineralization of the majority of nonbiodegradable 

compounds. 

Thus, the heterogeneous photocatalytic 

process was used for oxidation of pesticides 

(Mahmoodi et al., 2007; Kwan and Chu, 2003; 

Oreopoulou and Philippopoulos, 2003; Konstantinou 

and Albanis, 2002; Parra et al., 2002(a); Parra et al., 

2002(b); Higarashi and Jardim, 2000; Malato et al., 

2000; Gawlik et al., 1999), dyes (Subramani et al., 

2007; Byrappa et al., 2006; Miranda et al., 2006; 

Guettai and Amar, 2005; Bhattacharyya et al., 2004; 

Fernandez at al., 2004; Neppolian et al., 2003), 

phenol and phenolic compounds (Kusvuran et al., 

2005; Pandiyan et al., 2002, San et. Al., 2002; Peiro et 

al., 2001; Ilisz and Dombi, 1999) or substances that are 

contained in products for hygienic use (Couteau et al., 

2000), as well as for reduction of heavy metals (Chan 

and Ray, 2001; Datye at al., 1998). 

Among the numerous toxic pollutants, dyes 

may exhibit an eco-toxic hazard, introducing the 

potential danger of bioaccumulation that may 

eventually affect humans by transport through the 

food chain, hence their removal from wastewaters and 

sludge is highly requested. 

As dyes are designed to be chemically and 

photolytically stable, they are highly persistent in 

natural environments and, consequently, powerful 

tools for remediation of the environmental factors are 

necessary. 

The ineffectiveness of conventional methods 

such as adsorption, precipitation, chemical 

coagulation etc. for color removal led to the necessity 

to develop other efficient treatment processes. In this 

context, heterogeneous photocatalysis emerged as a 

very attractive alternative to the conventional 

treatment methods. 

∗ Author to whom all correspondence should be addressed: e-mail: anca_chem@yahoo.com

Caliman et al. /Environmental Engineering and Management Journal 6 (2007), 6, 483-489 

* In heterogeneous photocatalysis, conduction 

band electrons (e - ) and valence band holes (h + ) are 

generated by the irradiation of an aqueous TiO 2 

suspension with artificial or solar light having energy 

greater than the band gap energy of the 

semiconductor. The photogenerated electrons react 

with the adsorbed molecular O 2 on the Ti(III)-sites, 

reducing it to superoxide radical anion O 2 • - , while the 

photogenerated holes can oxidize either the organic 

molecules directly or the OH - ions and the H 2 O 

molecules adsorbed at the TiO 2 surface to hydroxyl 

radicals, which act as strong oxidizing agents. These 

can easily attack the adsorbed organic molecules or 

those located close to the surface of the catalyst, 

leading finally to their complete mineralization. 

In order to enhance the efficiency of 

heterogeneous photocatalysis, substances that act like 

electron acceptor are used, with the aim at preventing 

the electron-hole recombination by reacting with the 

excess electrons from the conduction band. Literature 

reports indicate the increase of the photocatalytic rate 

upon addition of different compounds, such as: H 2 O 2 

(Hofstadler and Bauer, 1994); K 2 S 2 O 8 (Shankar et al., 

2001); KBr (Al-Ekabi et al., 1993); AgNO 3 (Ilizs et al., 

1999); FeCl 3 (Sakthivel et al., 2000); potassium 

peroxymonosulphate (oxone) (Al-Ekabi et al., 1993); 

Fenton’s reagent (Malato et al., 2002). 

In this paper, the influence of two oxidizing 

agents, such as hydrogen peroxide and iron(III) salt, 

on the semiconductor mediated photodegradation of 

organic pollutants using aqueous solutions of cationic 

dye Alcian Blue 8 GX as model molecule, was 

studied. 


2.1. Regeants 

2.2. Procedures and analysis 

Experiments were carried-out in a closed 

Pyrex cell of 500 ml capacity, provided with ports, at 

the top, with the aim at bubbling air necessary for the 

reaction (Fig. 2). 

The reaction mixture was maintained as 

suspension by magnetic stirring. Previously 

irradiation, the reaction mixture was left 30 minutes 

in the dark in order to achieve the maximum 

adsorption of the dye onto the semiconductor catalyst 

surface. 

The irradiation was performed with a 9 W 

central lamp The spectral response of the irradiation 

source (Osram Dulux S 9W/78 UV-A, 14.5 cm length 

and 2.7 cm diameter), according to the producer is 

ranged between 350 and 400, with a maximum at 366 

nm and two additional weak lines in the visible 

region. The photon flow per unit volume of incident 

light was determined by chemical actinometry using 

potassium ferrioxalate. The initial light intensity, 

under exactly the same conditions in the 

photocatalytic experiments, was assessed as being 

7.16 Einstein min -1 . 

In all the cases, during experiments, 450 ml 

of Alcian Blue 8 GX solution containing appropriate 

amount of semiconductor powder was magnetically 

stirred before and during irradiation. Specific 

quantities of samples were withdrawn at periodic 

intervals and filtered through a 0.45 µm filter 

(Schleicher and Schuell) in order to remove the 

catalyst particles. 

With the aim at assessing the extent of color 

removal, changes in the concentration of the dye were 

observed from its characteristic absorption band using 

a UV-Vis spectrophotometer Shimadzu UV-160 A. 

The reactive Alcian Blue 8GX (Ingrain Blue 

1) with molecular formula C 56 H 68 Cl 4 CuN 16 S 4 and the 

average molecular weight M = 1298.86, a product of 

Sigma Chemie Gmbh was used as received. TiO 2 P- 

25 Degussa (anatase/rutile = 3.6/1, surface area 56 

m 2 g -1 ) and TiONa PC 500 (100% anatase, more than 

250 m 2 g -1 ), product of Millennium Chemicals, were 

utilized (Fig. 1). 

Fig.2. Experimental set-up for study of photocatalytic 

oxidation of Alcian Blue 8 GX 

Fig.1. Molecular structure of Alcian Blue 8 GX 

The photodecomposition was monitored 

spectrophotometrically at 609 nm in the absence and 

at 597 nm in the presence of iron salt, when linear 

dependences between the initial concentration of the 

Alcian Blue solution and these absorptions, for the 

two studied conditions, was obtained. 

484 4

Study concerning the oxidizing agents on heterogeneous photocatalytic degradation 

3. Results and discussions 

3.1. Comparison of photocatalytic degradation of 

Alcian Blue 8 GX in the presence of H 2 O 2 on two 

commercial catalysts 

In general, hydrogen peroxide contributes to 

the enhancement of the heterogeneous photocatalytic 

efficiency through generation of the hydroxyl radicals 

in the presence of light, as well as by scavenging the 

electrons, inhibiting hence, their recombination with 

the generated holes. However cases of a negative 

influence of H 2 O 2 were reported when the anatase 

form of the commercial catalysts was used in the 

system (Caliman et al., 2006; Velegraki et al., 2006). 

The efficiency of 15 minutes dark adsorption 

(a) as well as the efficiencies of the photocatalytic 

degradation (b) of 40 mg L -1 Alcian Blue 8 GX on 0.5 

g L -1 TiO 2 P-25, at the natural pH of solution (equal 

to 4.35 units) and in the presence of different amounts 

of H 2 O 2 (which were calculated for 20 minutes of 

irradiation, when data were available for the whole 

interval of studied concentrations of the oxidant 

ranged between 10 and 400 mg L -1 ) are presented in 

figure 3. 

The efficiencies for the two situations were 

calculated with the relations (1, 2): 

Ca 

− C 

0 

at 

η ads = 100 

(1) 

C 

a0 

C ph − C 

0 

pht 

η ph = 

100 

(2) 

C 

ph0 

where C a0 = concentration of the solution before the 

catalyst was added, C at = concentration after t minutes 

of dark adsorption (15 minutes), C ph0 = concentration 

of dye solution before UV irradiation and C pht = 

concentration of solution after t minutes of UV 

exposure. 

One may see that a strong adsorption of the 

dye in the presence of the oxidizing agent occurs. 

While at the natural pH of the solution, in the absence 

of a H 2 O 2 , the efficiency of the dark adsorption on 0.5 

g/L TiO 2 P-25 was of around 24%, in the presence of 

200 mg L -1 oxidant, it reaches almost 70%. This 

strong adsorption may be the result of decrease of the 

acidity of the environment through addition of H 2 O 2 , 

decrease that has a positive influence on the 

adsorption of the cationic dye on the catalyst surface, 

as it was shown in the study of pH influence upon the 

process, concordant to the data reported in a previous 

paper (Caliman et al., 2007). 

The effect of hydrogen peroxide resulted in an 

increase of the pH from the value of 4.35 units, in the 

absence of the oxidant, to 5.7 in the presence of 400 

mg L -1 H 2 O 2 , the average value of the pH in the limits 

of the used concentrations being equal to 5. 

At the same time, high amounts of hydrogen 

peroxide results in up to 90% color removal under 

irradiation. 

Analysis of the concentration of hydrogen 

peroxide revealed that 66%-74% of the oxidant 

remained in solution at the end of the photocatalytic 

process, when high concentrations of oxidant were 

used, as it is shown in Table 1. Thus, it may be 

observed that the oxidant was totally consumed when 

low concentrations of H 2 O 2 were added into the 

system, while at concentration above 100 mg L -1 

different percents of hydrogen peroxide remained 

unconsumed. This support the data depicted in Fig. 3, 

which shows that above this concentration, the 

photocatalytic efficiency is almost constant. 

dark adsorprtion effficiency (%) 

phtodegradation efficiency (%) 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

100 

no H 2 

O 2 

different concentrations of H 2 

O 2 

0 

-25 0 25 50 75 100125150175200225250275300325350375400425 

80 

60 

40 

20 

no H 2 

O 2 

H 2 

O 2 

concentration (mg L -1 ) 

different concentrations of H 2 

O 2 

0 

-25 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 

H 2 

O 2 

concentration (mg L -1 ) 

Fig.3. Influence of H 2 O 2 concentration upon dark 

adsorption (a) and photocatalytic degradation (b) 

efficiencies of 40 mg L -1 Alcian Blue 8 GX (0.5 g L -1 TiO 2 

P-25, pH = 4.35) 

The influence of H 2 O 2 was also studied in the 

case of other photocatalyst (TiONa Millennium) the 

results being compared with those obtained when 

TiO 2 Degussa was utilized (Fig.4). It is obviously that 

addition of the oxidant has a bigger influence in the 

case of P-25, when also strong adsorption of the 

(a) 

(b) 

485


intermediates is observed in the first minutes of 

irradiation. In the second case, the results concerning 

the degradation degree are not very much different, as 

data from the Table 2 reveal. 

absorbanta (609 nm) 

Table 1. Values of the percent of H 2 O 2 remained 

unconsumed at the final of the process 

0,8 

0,7 

0,6 

0,5 

0,4 

0,3 

0,2 

H 2 O 2 initial 

concentration 

mg L -1 

% H 2 O 2 in solution at the 

end of the process 

mg L -1 

10 - 

25 - 

50 - 

100 32 

200 66 

400 74.5 

0,5 g L -1 TiO 2 

P-25 

0,5 g L -1 TiO 2 

P-25 + 100 mg L -1 H 2 

O 2 

0,5 g L -1 TiONa 

0,5 g L -1 TiONa + 100 mg L -1 H 2 

O 2 

The efficiencies of the dark adsorption process 

(15 minutes) on 0,5 g L -1 P-25, respectively 

photocatalitic process, after 30 minutes of irradiation 

of 40 mg L -1 Alcian Blue 8 GX, in the presence of 

FeCl 3 are exhibited in Fig. 5. As one can see, the 

removal of color was mainly achieved in the dark 

period (70%), followed by a small variation of the 

process efficiency after irradiation, especially for the 

higher amounts of iron salt (>28 mg L -1 ). 

dark adsorption efficiency % 

100 

80 

60 

40 

20 

0 

0 7 14 21 28 35 42 49 56 63 

FeCl 3 

concentration, mg L -1 

(a) 

0,1 

0,0 

-20 0 20 40 60 80 

durata iradierii, min 

100 (b) 

Fig. 4. Influence of optimum concentration of H 2 O 2 (100 

mg L -1 ) on photocatalytic degradation of 40 mg L -1 Alcian 

Blue upon two different catalysts: TiONa and P-25 

(concentration of catalysts: 0.5 g L -1 ) 

Table 2. Comparison between degradation rates in the case 

of heterogeneous photocatalytic degradation of 40 mg L -1 

Alcian Blue 8 GX on two types of catalysts (TiONa and 

TiO 2 P-25 in the presence and, respectively, absence of 

H 2 O 2 

Concentration of 

catalyst or catalyst + 

H 2 O 2 

Reaction rate 

(mg L -1 min -1 ) 

Correlation 

coefficient 

R 

0.5 g L -1 TiO 2 P-25 0.62831 0.99396 

0.5 g L -1 TiO 2 P-25 + 100 1.16706 0.99913 

mg L -1 H 2 O 2 

0.5 g L -1 TiONa 0.62502 0.97736 

0.5 g L -1 TiONa + 100 mg 

L -1 H 2 O 2 

0.39774 0.95963 

3.2. Study concerning dark adsorption and 

photocatalytic degradation of Alcian Blue 8 GX on 

TiO 2 P-25 in the presence of FeCl 3 

Addition of FeCl 3 should have a positive effect 

on photocatalytic degradation of the organic 

compounds owing to generation of HO• in aqueous 

solutions with the participation of ferric ions and the 

products of their hydrolysis, although there were 

reported also cases of a detrimental action of the iron 

salt (Baran et al., 2003). 

photodegradation efficiency % 

80 

60 

40 

20 

0 

0 7 14 21 28 35 42 49 56 63 

FeCl 3 

concentration, mg L -1 

Fig. 5. Influence of FeCl 3 concentration upon dark 

adsorption (a) and photocatalytic degradation (b) 

efficiencies of 40 mg L -1 Alcian Blue 8 GX (0.5 g L -1 P-25, 

pH = 3.7) 

Considering the fact that the removal of color 

was observed mainly for the dark adsorption period, 

the study of the dark adsorption process appeared 

necessary in order to assess the influence of the iron 

salt upon this process. Thus, experiments concerning 

the measurement of the absorbance after 15 minutes 

of dark adsorption of 20 mg L -1 dye in the presence of 

different concentrations of catalyst P-25 only (Fig. 

6a) and also in the presence of 0.1 g L -1 catalyst and 

different amounts of FeCl 3 (Fig. 6b) were conducted. 

The values regarding the percents of color 

removal after dark adsorption were calculated with 

the following expression: 

486 4


A0 

− A 

% = 100 

(3) 

A0 

where: 

A 0 = absorbance of dye solution before adding 

catalyst, 

A = absorbance of dye solution after a certain time t. 

The calculated values are presented in Table 3 

for 1 minute and 15 minutes, respectively, of dark 

adsorption. 

is added in system, a competition must occur between 

its molecules and that of the dye for the active sites of 

the catalyst one can conclude that color removal may 

be the result not of adsorption but of precipitation of 

the formed insoluble complex formed by the dye with 

iron. 

Table 3. Dark adsorption efficiency (percent removal of 

color) at different concentration of TiO 2 P-25 and FeCl 3 , 

respectively 

abs/abs 0 

(609 nm) 

1,0 

0,9 

0,8 

0,7 

0,6 

0,5 

0,4 

0,3 

0,2 

0,02 g L -1 TiO 2 

P-25 

0,05 g L -1 TiO 2 

P-25 

0,1 g L -1 TiO 2 

P-25 

0,2 g L -1 TiO 2 

P-25 

Duration of dark 

adsorption of 20 

mg L -1 AB 8 GX 

% Removal of color at different catalyst 

concentration (g L -1 ) 

on P-25 (min) 0.02 0.05 0.1 0.2 

1 33.78 34.28 37.83 41.66 

15 45.94 36 40.54 37.77 

Duration of dark 

adsorption of 20 

mg L -1 AB 8 GX 

on 0.1 g L -1 P-25 

(min) 

% Removal of color at different 

concentration of FeCl 3 (mg L -1 ) 

14 28 56 

1 69.69 66.66 70.83 

15 78.84 78.18 75 

0,1 

0,0 

0 5 10 15 20 25 30 

dark adsorption time, min 

In the case of solution with very high amount 

of FeCl 3 (112 mg L -1 ), a smaller decrease of color 

removal (75%) was achieved after 15 minutes dark 

adsorption, while a higher one was observed after 

first minutes of irradiation (Fig. 7). 

abs/abs0 (597 nm) 

1,0 0,1 g L -1 TiO 2 

P-25 

0,8 

0,6 

0,4 

0,2 

0,0 

14 g L -1 Fe 3+ , pH = 3,5 

28 g L -1 Fe 3+ , pH = 3,55 

56 g L -1 Fe 3+ , pH = 3,45 

0 2 4 6 8 10 12 14 16 

dark adsorption time, min 

Fig. 6. Effect of concentrations of catalyst and iron salt, 

respectively, on dark adsorption of 20 mg/L Alcian Blue 8 

GX: abs/abs 0 vs irradiation time at various concentrations of 

TiO 2 P-25 (0.02-0.2 g L -1 ) (a) and abs/abs 0 vs irradiation 

time at various concentrations of FeCl 3 (14-56 mg L -1 ) (b) 

In the absence of FeCl 3 , it is obvious that the 

adsorption is very fast at the beginning, in the first 

minute being removed around 34-42 % of the dye 

color, after this time, the process becoming almost 

constant, with slow variation of dye concentration. 

Thus, after 15 minutes, which was the period of dark 

pre-equilibration of the dye solution in all the 

experiments, percents of color removal ranged 

between 36–46% were achieved. The same trend is 

also observed for the case of FeCl 3 presence in 

system, but the percent removal of color was higher 

(75-79%). Due to the fact that, generally, when FeCl 3 

absorbance (597 nm) 

0,7 

0,6 

0,5 

0,4 

0,3 

0,2 

0,1 

-20 -10 0 10 20 30 

irradiation time, min 

Fig. 7. Absorbance versus irradiation time for 

degradation of 40 mg L -1 Alcian Blue 8 GX on 0.5 g L -1 P- 

25 in the system containing very high amounts of FeCl 3 

(112 mg L -1 ) 

In order to check this behavior, another 

experiment was done with the system containing 112 

mg L -1 FeCl 3 that was subjected one hour to dark 

adsorption and one hour to irradiation (Fig. 8). One 

may observe that a significant decrease of the 

absorbance occurs in the first 20 minutes, remaining 

almost constant after this period and decreasing quite 

high again under the first 10 minutes of irradiation. 

It should be noticed that, while for 7-56 mg L -1 

FeCl 3 most of the dye color was removed in 15 

minutes of dark adsorption, in the case of using very 

high amount of iron(III) salt (112 mg L -1 ), removal of 

color of the solution in the adsorption process is 

smaller, as Figs. 7 and 8 show. The lower 

decolorization in the latter case may owe to the 

excess of Fe 3+ and colored products resulted from its 

487


hydrolysis, while the higher decrease of absorbance 

after 60 minutes of dark adsorption and 10 minutes of 

irradiation to be the results of transformation of the 

excess of colored Fe 3+ into colorless Fe 2+ concordant 

to the photo-Fenton reaction: 

Fe 3+ + hυ + H 2 O→ Fe 2+ + OH• + H + (4) 

After this period the efficiency of the UV 

exposure increased slower due to deposition on TiO 2 

of the precipitate formed in the reaction of the dye 

with the salt, which results in catalyst poisoning. 

When FeCl 3 is present in the system, the 

percents of color removal are higher (75-79%), as a 

result of precipitation of the insoluble complexes 

formed by the dye with the iron. However, the 

influence of the iron salt on the process under 

irradiation is rather negative. 

Acknowledgement 

Part of this study was done within the PN-II-ID-595 project: 

“Integrated studies on the behavior of persistent pollutants 

and risks associated with their presence in the 

environment”. 

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Fig. 8. Absorbance in the case of photocatalytic degradation 

of 40 mg L -1 on 0.5 g L -1 P-25 in the presence of 112 mg L -1 

FeCl 3 after 60 minutes adsorption in the dark and 60 

minutes irradiation (pH=3.7) 


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489

RIWATECH/Environmental Engineering and Management Journal, 6 (2007), 6, 490 

ADVANCED TREATMENT TECHNOLOGIES FOR RECYCLING 

INDUSTRIAL WASTEWATER 

RIWATECH - Research Grant no. 62 / 2005 of the Research for Excellency Programme 

(CEEX) 

The original approach of the RIWATECH 

project is the fact that it combines the aspects of all the 

major research& development, technology transfer, 

training and dissemination, so as to reduce pollutant 

loads and wastewater discharges, to implement the 

industrial wastewater recycling and to improve water 

management practices concerning the supply, usage, 

treatment and recycling of wastewater in the pulp and 

paper industry 

The RIWATECH Project is a direct response 

to the need for the Romanian industry to comply with 

the more demanding legislative requirements in the 

field of water and wastewater management, imposed by 

Romania’s recent EU adhesion, together with the 

industry’s need to improve its economic performances, 

given the increasing competition on the EU market. 

One of the means to achieve these two issues is to 

consider the recycling of industrial wastewater flows 

back into the technological process as process water, in 

order to improve both the environmental and economic 

performances of intensive water consuming activities, 

like the pulp and paper industry. 

Having this sustainable development approach 

in mind, a multidisciplinary research consortium 

formed by the “Gh. Asachi” Technical University of 

Iasi as project coordinator together with other 4 partners 

with high expertise, and experience in the field of 

wastewater treatment technologies (Politehnica 

University of Bucharest, Petru Poni Institute for 

Macromoleculary Chemistry of Iasi, Politehnica 

University of Timisoara and Transilvania University of 

Brasov) have proposed and won the funding of the 

RIWATECH Project within the Research for 

Excellency Programme (CEEX) of the Romanian 

Ministry of Education and Research. 

The Riwatech project has the following 

objectives: 

1. The development and implementation of 

advanced treatment technologies for recycling 

industrial wastewater from the pulp and paper industry 

so as to reduce the pollutant loads and wastewater 

discharges and to achieve water conservation; 

2. The improvement of management practices 

concerning water conservation, water usage, 

wastewater treatment and recycling of the effluent from 

the pulp and paper industry considering the 

implementation of the Integrated Pollution Prevention 

and Control (IPPC) and the Water Framework Directive 

(WFD); 

3. The development and implementation of 

continuous education programs and trainings in the 

field of Sustainable Water Management (considering 

the stages from water supply, water conservation 

towards wastewater recycling); 

4. The transferability of technological, monitoring, 

management and educational practices within the 

specific industry (pulp and paper branch); 

5. Dissemination of the most important results of 

the RIWATECH at the level of: national and 

international scientific community, of the industrial 

enterprises (pulp and paper and other industries), of the 

representatives of the environmental protection 

authorities (local/national) and of the civil society. 

To achieve the above objectives, the 

RIWATECH project uses an original approach for the 

implementation of its activities that combines the 

aspects of research and development, technology 

transfer and training and dissemination. The activities 

of the project include: research, development and 

demonstration of advanced wastewater treatment 

technologies to complete conventional treatment for the 

recycling of industrial effluents; the development of an 

integrated monitoring and control system for water 

supply, usage, conservation and treatment; development 

of pollution prevention and cleaner production practices 

for industrial water and wastewater management; 

technological transfer and dissemination of results. 

Until now, the consortium has studied five 

applicable advanced wastewater treatment processes in 

order to achieve wastewater recycling in the pulp and 

paper industry, has developed the integrated monitoring 

system that gives data on the technological production 

process and on the wastewater treatment process and 

has produced a pollution prevention and cleaner 

production measures manual for the pulp and paper 

industry. Currently, the consortium focuses on the 

technological transfer methodology by assessing the 

technical and economical performances of the five 

advanced treatment processes that have been previously 

studied in order to select the optimal one. The future 

activities of the project are focused on developing 4 

training modules to improve water resources 

management in industry, as well as to disseminate the 

results of the research activities. 

For more information on the RIWATECH 

Project, please visit: http://riwatech.cs.tuiasi.ro 

Project Director, 

Prof.dr.ing. Carmen Teodosiu 



cteo@ch.tuiasi.ro 

490




______________________________________________________________________________________________ 

NONMARKET VALUATION OF ACEQUIAS: STAKEHOLDER 

ANALYSIS 

Steven Archambault ∗ , Joseph Ulibarri 

University of New Mexico, Department of Economics MSC 05 3060, Albuquerque, NM 87131-0001, United States 

Abstract 

From a traditional market economy perspective, the productivity attained when water and land is used for acequias is much lower 

than the productivity achieved when applying these same resources to urban and industrial uses. An analysis of key stakeholders 

has indicated that there are cultural and environmental attributes of acequia agriculture landscapes that are not captured in the 

market-assigned value of acequias. This analysis revealed the motivations behind the value placed on acequias by government, 

developers, policy organizations, religious groups, and other stakeholders. Such context may not be fully captured in a 

quantitative nonmarket valuation study. This research also identified potential policy and management initiatives that could 

improve the nonmarket value of acequias. These include investments in less water intensive acequia infrastructure and agriculture 

techniques; supporting education and research of the cultural and environmental contributions of acequias; and promoting the 

interests in tourism in acequia communities. 

Key words: Nonmarket valuation, stakeholder, agriculture, acequias 


Acequia comes from the Arabic word 

“saqiya,” or water conduit, and refers to irrigation 

canals originally used in Iberia by Arab farmers. The 

technique, which diverts water from rivers to 

agricultural fields, was introduced in New Mexico by 

Spanish colonizers several hundred years ago (Brown 

and Rivera, 2000). Through the present day, acequias 

have been collectively owned and democratically 

governed by members of the acequias de común. 

Mayordomos (ditch bosses) are democratically 

appointed to provide executive leadership for 

community maintenance of the acequias, and to 

oversee the distribution of acequia water (Rivera, 

1998). With the scarcity of water and frequency of 

droughts due to the desert climate, the early 

development of villages and towns in New Mexico 

relied heavily on water from acequias to grow maize, 

vegetables, and other crops. 

During the 1900s, with the arrival of new 

economic and development opportunities, acequias 

became less important for providing the survival 

needs of New Mexico’s communities. In the last 

several decades, the output from acequia agriculture 

production has had much less value than the 

productivity achieved when acequia land and water is 

used for urban development, industrial production, 

and other economic activities (Rivera and Martinez, 

2000). Additionally, increased environmental 

demands for water to be used to maintain river flows 

have called into question the continued utilization of 

water for acequias. Despite these pressures, over 1000 

acequias continue to operate in New Mexico (Brown 

and Rivera, 2000). Many stakeholders advocate that 

the cultural significance of acequias is reason enough 

to support their existence. Further, it is suggested that 

acequias provide important environmental 

contributions, including buffering against floods, 

contributing to riparian habitat, and adding to the 

recharge of groundwater systems (Brown and Rivera, 

2000). The objective of this research is to explore and 

understand the context in which acequias provide 

value through their nonmarket cultural and 

environmental attributes, and to identify measures 

that may lead to increases in this value. 

∗ Author to whom all correspondence should be addressed: sarchamb@unm.edu

Archambault and Ulibarr/Environmental Engineering and Management Journal 6 (2007), 6, 491-495 

Economists classify environmental and 

cultural attributes as nonmarket goods, which do not 

have prices and cannot be traded in a traditional 

market place. Valuation studies are carried out to 

name a monetary figure to represent society’s 

willingness-to-pay (WTP) for nonmarket goods. 

Valuation techniques have traditionally been used to 

capture the nonmarket value of environmental goods, 

although the techniques have been expanded to 

capture the value of cultural and agriculture 

amenities. Brunstad et al. (1999) suggested that the 

total value of agriculture should not only include the 

market value of products produced, but also take into 

account agriculture landscape amenities, such as open 

space and tree cover, the security of food production 

capacity, and the preservation of rural communities 

and rural lifestyles. Understanding the full value of 

agriculture production, beyond solely the market 

value of agricultural output, can be used to weigh the 

costs and benefits to society of policy measures that 

impact agricultural production. 

There have been a number of previous 

nonmarket valuation studies of agriculture 

landscapes, several are mentioned here. Hedonic 

pricing studies have determined that the presence of 

agricultural open space, pastureland, and irrigation 

water increased property values and rents of nearby 

residences, while the presence of large animal farms 

decreased the value of these nearby properties (Faux 

and Perry, 1999; Ready and Abdalla, 2005). 

Employing the contingent valuation method (CVM), 

surveys have asked respondents their WTP for 

hypothetical changes to a landscape that could 

potentially impact the existing agricultural attributes, 

such as the amount of grazing land utilized, or the 

chosen conservation and land management strategies 

(Berrens et al., 1998; Schlapher and Hanley, 2003). 

The primary purpose of nonmarket valuation 

studies is to discover a quantitative value for 

nonmarket goods. However, valuation studies have 

been criticized for not including input from 

organizational structures that have specific interests 

in, and knowledge of, the nonmarket good in 

question. It is argued that there is a need to analyze 

the key stakeholders, institutions, and agencies that 

are interconnected with the good to fully understand 

the context in which nonmarket values are perceived 

by society (Kontogianni, et al., 2001). Stakeholder 

analyses have become increasingly popular tools for 

evaluating the role various stakeholders have in 

influencing policy (Brugha and Varvasovszky, 2000). 

Ecological modernization studies use stakeholder 

analyses to understand the political ecology of an 

industry, to determine strategies for integrating 

policies and activities that promote principles of 

sustainability in the industry (Archambault, 2004). 

The contribution of this research is to use a 

stakeholder analysis to qualitatively explore the 

context with which environmental and cultural 

attributes of traditional agriculture practices are 

deemed valuable by society. This analysis is then 

used to identify management and policy initiatives 

that increase the value of these attributes. 

2. Case Study: Acequia stakeholder analysis 

The stakeholder analysis carried out for this 

study relied primarily on secondary data collected 

from academic journal articles, as well as government 

and non-government policy and report documents. 

Meetings were carried out with members of New 

Mexico’s legislative finance committee, Think New 

Mexico, and academic researchers. Other agencies 

were contacted via email. The primary purpose of this 

communication was to verify interpretation of the 

documents reviewed. 

2.1. Governmental agencies 

A brief database search of New Mexico state 

law turns up a number of rules that pertain to the 

operation, maintenance, preservation, or water rights 

of acequias (NMCC, 2007). In 2005, the state 

government put in place the Strategic Water Reserve, 

which allows the state to buy or lease water rights 

from users to ensure rivers and streams have the 

legally required quantities of water to be delivered to 

nearby states, and to maintain levels needed by 

endangered river ecosystems (New Mexico, 2005). 

Under the law, the Interstate Stream Commission 

(ISC) is given the power to purchase or lease water 

rights from willing sellers for a price no greater than 

the appraised market value. However, the policy does 

not allow water to be purchased from acequia 

communities. Additionally, state and federal funds are 

available for acequia rehabilitation and improvement 

projects. In 2004, the state’s funding share to these 

projects was $2.4 million (ISC, 2004). 

One of the major players for water use in New 

Mexico are the quasi-government irrigation districts 

that regulate and distribute water according to the 

state’s established doctrine of prior appropriation, 

whereby those who have been using the water the 

longest have the most senior water rights (Thompson, 

1986). This hierarchy means that users with junior 

rights may not receive water in times of low supply. 

The Middle Rio Grande Conservancy District 

(MRGCD) was created in the early 1900s through the 

incorporation of seventy-nine independent acequia 

communities who recognized the need to coordinate 

the use of water from the Rio Grande (MRGCD, 

2007). However, with the rapid development of urban 

and industrial centers, the MRGCD must now balance 

the various demands placed on this surface water 

(Thompson, 1986). Because acequia communities 

collectively hold senior water rights, the MRGCD and 

other irrigation districts must give them higher 

priority for water delivery. 

The exemption for acequias in the Strategic 

River Reserve, the funds provided annually to 

acequias, and the mechanism of protecting senior 

water rights indicates that the state recognizes that 

acequias have value to New Mexico. The support 

492

Nonmarket valuation of acequias: stakeholder analysis 

provided by the state ensures acequias are able to 

continue their operations. 

2.2. Local development 

Local city governments have to contend 

directly with the conflicting demands on water and 

land resources from acequias and urban development. 

One example of balancing growth and acequia 

cultural preservation is seen in the agricultural village 

of Los Lunas, located just south of large city of 

Albuquerque. Los Lunas has relied on acequias for 

many generations, but now faces pressure to develop 

residential communities for its rapidly growing 

population. The Los Lunas comprehensive plan 

emphasizes the need for a mode of development that 

maintains their agricultural heritage (Los Lunas, 

1999). The interest and struggles of communities to 

maintain acequias despite development pressures, 

underscores the presence of a cultural value held for 

acequias. 

2.3. Policy advocacy groups 

There are different special interest groups, 

think tanks, and policy lobbyists who advocate for 

specific policy objectives that concern acequias. 

Think New Mexico is an advocacy organization that 

was extensively involved in promoting the 

implementation of the strategic water reserve, and 

lobbied for acequias to be exempt from transferring 

water to the reserve. Their policy documents call 

attention to the unique social, cultural, and ecological 

benefits of acequias that would be damaged if the 

reserve policy transferred water away from acequias. 

They mention the millions of dollars New Mexico is 

able to generate from tourists who come to experience 

the state’s cultural heritage, of which acequias play a 

visible role (Think New Mexico, 2003). 

Another advocacy group is the New Mexico 

Acequia Association (NMAA). NMAA was founded 

in 1990 to serve as a platform for expressing the 

common concerns and goals of acequia communities 

around the state. Acequia users and other interested 

parties pay dues to have membership in the NMAA. 

The association organizes people and resources to 

meet goals, provide education, and advocate for 

policies that are in the interest of acequia 

communities. The association particularly calls 

attention to its mission of sustaining the acequia 

culture and traditions, protecting water as a 

community resource, and maintaining the ability to 

grow food (NMAA, 2007). 

One category of special interest groups 

includes those groups with specific interests in 

promoting environmental issues. The Forest 

Guardians are particularly vocal about their interest in 

maintaining healthy river ecosystems. They have 

concern for the large quantities of water required for 

some agriculture activities, including the growing of 

alfalfa, which many modern acequia communities 

produce (Forest Guardians, 2007). However, many 

environmental advocacy groups do not promote the 

termination of acequia culture. Instead, they 

emphasize the contribution acequias make to the 

cultural landscape, and propose ways that acequias 

could be managed in the most environmentally 

feasible manner, so there is water available for both 

acequias and instream flows. Possible techniques 

include growing valuable crops that use less water 

(Brown and Rivera, 2000). A series of environmental 

organizations, including Forest Guardians, made a 

statement in 2000, saying that increasing the 

efficiency of agriculture irrigation is the most 

effective way to increase river flows and maintain 

river habitats (Alliance for the Rio Grande Heritage et 

al., 2000). This statement indicates that acequias have 

a potentially valuable role to play in managing New 

Mexico’s scarce water resources. 

2.4. Religious organizations 

Historically, the predominant religious 

institution in New Mexico is the Roman Catholic 

Church. There is evidence in activities of the Church 

that highlights the cultural significance of acequias. 

The Archdiocese of Santa Fe has an Ecology Ministry 

through their Peace and Social Justice Office, which 

advocates for acequia communities. Along with 

community and environmental organizations, such as 

Amigos Bravos, the Church is involved with the 

annual Fiesta de San Isidro, where acequias are 

blessed and a traditional Catholic Mass is held 

(Amigos Bravos, 2007). The work of the Church to 

support and advocate for acequia culture represents 

the Church’s recognition that acequias contribute 

value to New Mexico communities. 

2.5. Academic research 

Academic research also gives some insight 

into the cultural value of acequias. The hypothesis is 

that if there are large numbers of researchers involved 

with studying acequia culture and activity, one might 

conclude that acequia culture has a level of 

importance in New Mexico. Social research 

concerning acequias has included acequia history and 

culture (Rivera, 1998), acequia legal structure 

(Delara, 2000), and efficiency, equity and shared 

resource studies (Klein-Robbenhaar, 1996). 

3. Discussion and policy implications 

This analysis has indicated that stakeholders 

look beyond market economics, and assign value to 

acequias based on their unique social structure, 

cultural and traditional heritage, and actual and 

potential environmental contributions. There are also 

characteristics of acequias that may diminish their 

nonmarket value, including interference with urban 

and industrial development, as well as inefficient use 

of water. There is specific environmental concern that 

acequias leave less water available for endangered 

river ecosystems. 

493

Archambault and Ulibarr/Environmental Engineering and Management Journal 6 (2007), 6, 491-495 

The stakeholder analysis allows for the 

identification of points of intervention where policy 

measures or activities can be implemented to 

strengthen the cultural and environmental attributes of 

acequias. Through the government’s support of 

acequia rehabilitation, methods could be introduced 

that decrease acequia water consumption. The 

government could support lining the acequias to 

minimize seepage, or fund the removal of non-native 

trees that consume large amounts of water along 

acequia banks. The government and policy groups, 

such as NMAA and environmental organizations, 

should encourage acequias to grow crops that are less 

water intensive. These organizations may aim to 

educate farmers about such subjects as drip irrigation 

and other techniques that would reduce the water 

needed for crops. Improving their environmental 

performance is likely to cause stakeholders and the 

general public to increase the value they assign to 

acequias. 

Increases in the cultural value achieved from 

acequias may be wrought through the promotion of 

tourism that focuses on New Mexico’s acequia 

cultural heritage. Tourism could further promote the 

benefits of the riparian habitats associated with 

acequias, bringing visitors to view birds and other 

wildlife that are found in the bosque habitat. Such 

improvements may also bring added value to the 

residential neighborhoods that exist or are being 

planned near acequias. Developers may recognize the 

benefit of maintaining the environmental and cultural 

attributes of acequias, to increase the value of their 

development projects. 

The nonmarket values of acequias are likely to 

increase if society is more familiar with the 

environmental and cultural contributions acequias 

provide. This could be achieved through educational 

and promotional efforts, and through the sponsorship 

of academic research focused on acequias. 


Infrastructure changes, the promotion of 

tourism, and educational activities are likely to 

require additional investment by the government and 

other organizations. A quantitative study of acequia 

nonmarket value could assist in determining society’s 

WTP for acequias, through increased taxes, fees, or 

other payment vehicles. The current dollar figure 

spent by the government to support acequias may be 

either below or above society’s WTP. An actual WTP 

value would assist the state in designing a more 

accurate budget for acequia support. A hedonic study 

may assist developers in adjusting their projects to 

account for additional revenue they may receive from 

striving to maintain acequias within their urban 

development projects. A travel cost study may 

indicate the WTP of tourists for certain acequia 

cultural and landscape amenities when they visit New 

Mexico. 

The stakeholder analysis approach is useful for 

unraveling the complexities that may exist in valuing 

an activity or policy. It draws attention to those 

potentially competing stakeholder preferences for 

nonmarket goods. In this study, stakeholders are seen 

to recognize a non-market value of acequias. 

However, the actual monetary value placed on 

acequias by the government, local developers, 

members of the Church’s ecological ministry, 

environmental groups, and other stakeholders is likely 

to vary. Such context is useful for fully interpreting 

nonmarket valuation estimates. Understanding the 

value preferences of individual stakeholders allows 

for policy and management decisions that may lead 

the way to strengthened cultural and environmental 

attributes to maximize the utility of all stakeholders. 

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SIWMANET/Environmental Engineering and Management Journal, 6 (2007), 6, 496 

SUSTAINABLE AND INTEGRATED WATER RESOURCES 

MANAGEMENT NETWORK- SIWMANET 

Research Grant no. 115 / 2006 of the Research for Excellency Programme (CEEX) 

The context of sustainable water management 

requires an integrated approach that considers, in 

association with specific policies and legal 

frameworks, multidisciplinary research (sciences, 

engineering, management), education and training, 

communication, public participation and cooperation 

at both national and international scale, embedded in 

an overall approach that consider water flow and 

usage in its cycle of supply, use and reuse/recycling, 

affected either by natural or human factors. In the 

framework of the CEEX Research for Excellency 

Programme of the Romanian Ministry of Education 

and Research (Module III), a consortium lead by the 

“Gh. Asachi” Technical University of Iasi which has 

as partners Politehnica University of Timisoara, 

Politehnica University of Bucharest, Transilvania 

University of Brasov and North University of Baia 

Mare has received financing through grant 

competition for the SIWMANET project. Supporting 

project partners are: Technical University of Munich, 

Germany; International Institute for Industrial 

Environmental Economics, Lund University, Sweden; 

University of Manchester, United Kingdom; Institute 

for Advanced Studies on Sustainability, Munich, 

Germany; Technical University of Denmark. 

The major objective of the SIWMANET 

project is the development of a network formed from 

poles of excellence in research in the field of 

sustainable and integrated water resources 

management, a network that is capable of attracting 

co-operations in both international and national 

programs (due to its existent expertise in 

environmental sciences, engineering and 

management, the existent and potential collaborations 

with universities from Romania and abroad and the 

well balanced national distribution of the project 

partners), so as to increase the visibility of the 

Romanian universities and their participation at the 

European and international research programs. 

The specific objectives are listed below: 

1. Development of the capacities of Romanian 

researchers to participate as coordinators of workpackages 

or projects in European programs such as FP7 or any other 

EC/international programs; 

2. Development of viable partnerships at European 

level that would further facilitate the research cooperation 

and knowledge transfer in the field of sustainable and 

integrated water management and in general of sustainable 

development; 

3. Correlation and visibility of the Romanian 

research for excellence activities with the European 

programs for integrated water resources management, in 

the fields of policies, research, knowledge transfer and 

dissemination; 

4. Dissemination of the significant project results at 

the level of the national and international scientific 

community, to the governmental organisations dealing with 

integrated water management (WaterWorks and Water 

Supply companies, Environmental Protection Agencies, 

local and regional authorities), as well as to the civil 

society. 

The whole structure of the SIWMANET 

project and its activities relies upon the integrated 

concept of managing the water resources, and the 

relations that can be established for each level or 

water use, reuse, protection of ecosystems and human 

health with the major stakeholders 

The SIWMANET Project mainly includes the 

following activities: 

• Promotion of the existent researches and potential 

of the Romanian universities (through short and 

medium research stages of the Romanian young and 

senior researchers/scientific personalities, 

participation in training sessions and in proposal 

preparation seminars for European projects, exchange 

of results and experiences between the Romanian and 

European researchers through knowledge transfer and 

dissemination of the corresponding S/T results); 

• Organisation of national and international 

scientific events with invited European scientific 

personalities; 

• Organisation and participation at meetings and 

support activities concerning the development of the 

Water Supply and Sanitation Technology Platform or 

ERA-net projects. 

The international events include: 

- organisation of an international workshop using 

the European Awareness Scenario Workshop methodology 

to involve co-operation of stakeholders in sustainable and 

integrated water resource management and to depict the 

main directions of research in Romania in relation to the 

European policies, current developments and activities; 

- co-organisation of the 4 th International 

Conference on Environmental Engineering and 

Management (ICEEM04) which brings together engineers, 

scientists and managers, activating in the field of 

environmental protection, from universities, industry, local 

authorities, policy makers and non-governmental 

organizations, to discuss and analyze environmental 

problems, to share practical solutions and information on 

recent developments and to contribute to public awareness 

and ecological education and thus contributing to 

sustainable development. 

For these two events, an important role will be 

played by the internationally recognized personalities 

in the field of integrated water resources management 

that have accepted to cooperate within the 

SIWMANET Project as supporting partners. For 

additional information regarding the SIWMANET 

Project please visit its site at: 

http://instrumentation.cs.tuiasi.ro/sites/siwman 

et/default.aspx. 

Prof.dr.ing. Carmen Teodosiu, Project Director 


“Gh. Asachi” Technical University of Iasi, Romania, cteo@ch.tuiasi.ro 

496




______________________________________________________________________________________________ 

METALS CONCENTRATION IN SOILS ADJACENT 

TO WASTE DEPOSITS 

Camelia Drăghici 1 , Elisabeta Chirilă 2∗ , Narcisa Elena Ilie 2 

1 Transilvania University of Brasov, 29 Eroilor Blvd. 500036 – Brasov, Romania 

2 “Ovidius” University, Chemistry Department, 124 Mamaia Blvd., 900527 Constanta, Romania 

Abstract 

The paper presents original results concerning concentrations of eight heavy metals in soils adjacent to two improperly built 

municipal waste deposits located in Eforie Sud and Techirghiol, Constanta County, Romania. Measurements have been done on 

surface and depth soils, during April-October 2006. The applied analytical technique for metal determination was flame atomic 

absorption spectrometry (FAAS). The mean measured values ranged as follows (in mg/kg dry weight): Cd: 0.09 – 0.15; Co: 7.92 - 

9.27; Cr: 11.37 – 13.86; Cu: 16.91 – 20.92; Mn: 379 – 441; Ni: 20.58 – 28.95; Pb: 7.24 – 9.08 and Zn: 44.28– 49.93. Except 

nickel all other metals concentrations have been founded below the accepted limits by the Romanian regulations. As a general 

observation, in depth soil samples the concentrations were higher for Cr, Cu, Ni and Pb, or similar for Mn, Zn, than in surface 

samples. Cadmium and cobalt have different concentration evolution between depth and surface samples, in the studied locations. 

Key words: heavy metals, soils, FAAS, waste deposits 


Soils and sediments are the solid components 

of terrestrial and aquatic ecosystems which serve as 

sources and sinks for nutrients and solid chemicals. 

The use of soils for industrial, agriculture and urban 

activities always involves a drastic modification of 

their composition and can eventually create enormous 

problems for its future use, involving high capital 

investments and health risks. (Manea, 2004). 

Soil pollution is defined as the build-up in 

soils of persistent toxic compounds, chemicals, salts, 

radioactive materials, or disease causing agents, 

which have adverse effects on plant growth and 

animal health. The degree of antropogenous effect of 

metal cycles can be represented as a global 

interference factor: it indicates the ratio of the 

antropogenously-induced amount of material to that 

of the natural (geochemical) material cycle. Processes 

in the geochemical cycle that are common are 

equilibriums of dissolution-precipitation, the 

transition of metal compounds in aerosols and the 

return to the soil and water via precipitations 

(Schwedt, 2001). 

The term municipal solid waste (MSW) is 

used to describe most non-hazardous solid waste from 

a city, town or village that requires routine collection 

and transport to a processing or disposal site. MSW is 

not generally considered hazardous. But certain types 

of commercial and industrial wastes like those 

poisonous, explosive or dangerous can cause 

immediate and direct harm to people and the 

environment if they are not disposed of properly. Soil 

contamination as well as surface water and ground 

water pollution can be caused by the disposal of solid 

waste in improperly built landfills. These kinds of 

pollution problems can have important public health 

consequences (Manea, 2003). In “typical European 

household waste”, batteries contained 93% of the 

mercury and 45% of cadmium, ferrous metals 

accounted for about 40% of the lead, the fine 

(

Draghici et al. /Environmental Engineering and Management Journal 6 (2007), 6, 497-503 

waste tended to be concentrated in the metal wastes, 

batteries and electronic equipment and tended to have 

elevated concentrations of cadmium compared to the 

other fractions in plastics (Burnley, 2007). 

Heavy metals or trace metals is the term 

applied to a large group of trace metals which are 

both industrially biologically important. Agricultural 

productivity can be limited by deficiencies of 

essential trace elements such as Cu, Mn and Zn in 

crops and Co, Cu, Mn and Zn in livestock. However, 

when are presented in excessive concentrations, 

certain heavy metals give rise to concern with regard 

to human health and agriculture (Dobra and Viman, 

2006; Statescu and Cotiusca-Zauca, 2006) and their 

accurate analytical determination remains a challenge 

for chemists (Anderson, 1999; Baiulescu et al., 1990; 

Crompton, 2001; Draghici et al., 2003). The purpose 

of this paper is to present original results concerning 

concentrations of eight metals in soils adjacent to 

Eforie Sud and Techirghiol improperly built 

municipal waste deposits located in Constanta 

County, Romania, in April-October 2006. 


Total Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn 

concentrations in soils using flame atomic absorption 

spectrometry (FAAS) have been determined. 

Adjacent soils of two improperly built landfills 

located in Constanta County, Romania have been 

analysed: Eforie Sud waste deposit, corresponding to 

8650 people and Techirghiol waste deposit which 

corresponds to 7150 people. 

In order to determine metals concentration 

from soils, five samples were collected using a 

special device from the surface and depth of 20-40 

cm from each location at 1 – 2.5 m distance of the 

landfill boundary between April and October 2006 

(Chirila, 2004). Mean samples from surface and depth 

have been obtained each month by the appropriate 

omogenization of collected samples, previously dried 

for 16 hours at room temperature. 

To obtain soil solutions, 3 grams of soil 

sample has been extracted with aqua regia in 250 mL 

volumetric flask (ISO 11466). The supernatant, the 

filtrate and the washing solution have been collected 

in 100 mL calibrated flask (Chirila and Draghici, 

2003). 

The spectrometric measurements have been 

done using a flame atomic absorption spectrometer 

Spectr AA220, provided by Varian Company. 

Analyses have been done in triplicate and the mean 

values are reported. 

For the background correction, the zero 

calibration solution was done using aqua regia and 

deionised water (for Cd, Co, Cu, Ni, Pb and Zn); for 

Cr and Mn, the zero calibration solution was prepared 

by adding of 3.7 mg/L La, using a lantanum chloride 

solution. All used reagents were of spectral purity 

grade. 


Heavy metals existence in the soil can be 

explained by the natural concentration of (that 

depends on the soil type and its composition) and by 

soil contamination with heavy metals, provided by 

human activity. Soil pollution with heavy metals can 

be available from infiltration of highly contaminated 

storm water. 

The studies were performed in order to 

observe the heavy metal concentration evolution in 

adjacent soils to solid waste deposits. Once metals are 

introduced and contaminate the environment, they 

will remain. Metals neither are nor degraded like 

carbon-based (organic) molecules. 

The measured concentrations have been 

compared with the Romanian regulations (Table 2). 

Table 2. Regulatory limits for heavy metals in soils (after 

756/1997 – Romanian regulation of environment pollution 

evaluation) 

Metal Concentration, mg/kg dry weight 

Normal Alert limit Intervention limit 

value S NS S NS 

Cd 1 3 5 5 10 

Co 15 30 100 50 250 

Cr 30 100 300 300 600 

Cu 20 100 250 200 500 

Mn 900 1500 2000 2500 4000 

Ni 20 75 200 150 500 

Pb 20 50 250 100 1000 

Zn 100 300 700 600 1500 

S- sensible utilization, NS non-sensible 

Cadmium concentration in soil depends on 

the geological origin of the parent material, texture, 

intensity of weathering processes, organic matter and 

other factors. Cadmium enters the soil in smaller 

quantities than lead and it reach the soil through air. It 

is derived from incinerator exhaust gases and from 

phosphate fertilizers. Generally, in acidic soils with 

pH


environment are soil, dust, seawater, volcanic 

eruptions and forest fires. All soil contains some 

amount of cobalt. The average concentration of cobalt 

in soils around the world is 8 mg/kg dry weight. 

Toxic effects on plants are unlikely to occur below 

soil cobalt concentrations of 40 ppm. One of the most 

important soil properties is soil acidity. The more 

acidic the soil, the greater are the potential for cobalt 

toxicity, at any concentration. 

Co conc., mg/kg 

d.w. 

16 

14 

12 

10 

8 

6 

4 

2 

0 

a) 

Apr Iun Aug Oct 

month 

surface 

depth 

b) 

Co conc., mg/kg d.w. 

14 

12 

10 

8 

6 

4 

2 

0 


month 

surface 

depth 

Fig. 2. Cobalt concentration evolution in soil adjacent to 

waste deposits in April-October 2006 (mean values, mg/kg 

dry weight); a) Eforie Sud; b) Techirghiol 

Fig. 1. Cadmium concentration evolution in soil adjacent to 



The cobalt concentration evolution in studied 

soil samples are presented in the Fig. 2. 

All founded values are lower than 15 mg/kg 

dry weight, the normal Co concentrations in soil. 

Chromium is a trace component in the earth’s 

crust (0.02%), a unique element in soil, because of 

essentiality to human and animal life and nonessentiality 

for the vegetable kingdom and its possible 

presence in two main oxidation forms, trivalent and 

hexavalent which show opposite properties. The 

reported mean total chromium concentration in 

lithosphere is 69 mg/kg dry weight. The two forms 

have completely different effects on living organisms: 

the first Cr(III) is apparently useful or harmless at 

reasonable concentrations, while the second Cr(VI) is 

extremely toxic. In addition, Cr(III) is not mobile in 

soil, therefore the risks of leaching are negligible, 

while Cr(VI), mainly present in the forms of 

chromates (CrO 4 2− ) and dichromates (Cr 2 O 7 2− ), is 

generally mobile and often is part of crystalline 

minerals. 

Conversion of Cr(III) to Cr(VI) has been 

shown in some particular soils: rich in manganese 

oxides, poor in organic matter and high redox 

potential. On the contrary, the reverse transformation 

of Cr(VI) to Cr(III) is very common and easier, so 

that it is difficult to find hexavalent chromium forms 

in soil solution or in leaching waters. The problem of 

Cr enrichment in soil has been often discussed not 

only in relation to the discharge of tannery wastes, but 

also to the possibility of Cr presence in soil 

amendments, mainly organics, and to the existence of 

excellent organic fertilizers produced from leather 

residues or wastes. 

Fig. 3 presents the mean total chromium 

concentration in studied soil samples. 

In Eforie Sud soil samples Cr concentration 

ranged between 3.24 – 28.72 mg/kg dry weight in 

surface samples and 7.25 – 30.06 mg/kg dry weight in 

depth samples. Soil samples from Techirghiol 

registered similar Cr concentrations (7.50 – 28.55 

mg/kg dry weight in surface samples and 8.40 – 19.32 

mg/kg dry weight in depth samples). All determined 

Cr concentrations were below the normal limit in soil. 

Copper is also a trace element in the earth’s 

crust (0.007%); Cu is among the trace elements 

essential for life, in the case of plants toxic effects 

occur at 20 or more mg/kg dry weight. In the past, the 

499


major source of Cu pollution was smelters that 

contributed vast quantities of Cu–S particulates to the 

atmosphere. 

a) 

22.11 mg/kg dry weight in depth samples). The 

determined Cu concentrations in Eforie Sud soils 

sometimes slowly exceeded the normal limit in soil. 

Another observation consists in the fact that copper 

concentration is higher in depths samples than in the 

surface samples in both locations. 

30 

25 

a) 

Cr conc., mg/kg d.w. 

20 

15 

10 

5 

0 

Apr May Iun Iul Aug Sept Oct 

month 

surface 

depth 

Cu conc., mg/kg d.w. 

50 

40 

30 

20 

10 

0 


surface 

depth 

b) 

month 

Cr conc., mg/kg d.w. 

30 

25 

20 

15 

10 

5 

0 


month 

Fig. 3. Chromium concentration evolution in soil adjacent 

to waste deposits in April-October 2006 (mean values, 

mg/kg dry weight); a) Eforie Sud; b) Techirghiol 

surface 

depth 

Presently, the burning of fossil fuels and waste 

incineration are the major sources of Cu to the 

atmosphere and the application of sewage sludge, 

municipal composts, pig and poultry wastes are the 

primary sources of anthropogenic Cu contributed to 

the land surface. The amount of Cu available to plants 

varies widely by soils. 

Available Cu can vary from 1 to 200 ppm 

(parts per million) in both mineral and organic soils 

as a function of soil pH and soil texture. Availability 

of Cu is related to soil pH and texture. As soil pH 

increases, the availability of this nutrient decreases 

and the finer-textured mineral soils generally contain 

the highest amounts of Cu. Copper is not mobile in 

soils, being attracted to soil organic matter and clay 

minerals. Toxic at high doses, excess Cu can lead to 

Zn deficiencies and vice-versa. 

Fig. 4 presents the mean copper concentration 

in studied soil samples. 

In Eforie Sud soil samples Cu concentration 


surface samples and 13.37 – 47.60 mg/kg dry weight 

in depth samples. Soil samples from Techirghiol 

registered similar Cu concentrations (15.80 – 19.25 

mg/kg dry weight in surface samples and 16.25– 

Cu conc., mg/kg d.w. 

25 

20 

15 

10 

5 

0 


month 

Fig. 4. Copper concentration evolution in soil adjacent to 



Manganese is a less abundant major 

component (0.1%) in the earth’s crust. The major 

anthropogenic sources of environmental manganese 

include municipal wastewater discharges, sewage 

sludge, mining and mineral processing (particularly 

nickel), emissions from alloy, steel, and iron 

production, combustion of fossil fuels, and, to a much 

lesser extent, emissions from the combustion of fuel 

additives. Mean reported Mn concentration in soils is 

300–600 mg/kg dry weight. Availability of Mn 

increases as soil pH decreases. Soils with a high 

organic matter and neutral pH will be low in Mn. As 

the organic matter increases the complexing of Mn 

with organic matter also increases. Soils high in 

organic matter will usually be low in available Mn. 

The role of Mn in plants was discovered in 1922. It is 

essential for photosynthesis, production of 

chlorophyll and nitrate reduction. Plants which are 

deficient in Mn exhibit a slower rate of 

photosynthesis by as much as half of a normal plant. 

Plants which are low in Mn causes other 

metals such as iron to exist in an oxidized and 

b) 

surface 

depth 

500


unavailable form the reduced form of metals are 

available for metabolism. 

The mean manganese concentrations in 

studied soil samples are presented in the Fig. 4. 

In Eforie Sud soil samples Mn concentration 

ranged between 235 – 665 mg/kg dry weight in 

surface samples and 247 – 628 mg/kg dry weight in 

depth samples. 

a) 

Nickel is essential to maintain health in 

animals. Although a lack of nickel has not been found 

to affect the health of humans, a small amount of 

nickel is probably also essential for humans. Fig. 6 

presents the mean nickel concentration in studied soil 

samples. 

35 

a) 

30 

Mn conc., mg/kg 

d.w. 

700 

600 

500 

400 

300 

200 

100 

0 


month 

surface 

depth 

Ni conc., mg/kg d.w. 

25 

20 

15 

10 

5 

0 


month 

surface 

depth 

b) 

Mn conc., mg/kg 

d.w. 

700 

600 

500 

400 

300 

200 

100 

0 

b) 


month 

Fig. 5. Manganese concentration evolution in soil adjacent 

to waste deposits in April-October 2006 (mean values, 

mg/kg dry weight); a) Eforie Sud; b) Techirghiol 

surface 

depth 

Soil samples from Techirghiol registered 

higher Mn concentrations (343 – 684 mg/kg dry 

weight in surface samples and 382 – 616 mg/kg dry 

weight in depth samples). All founded values are 

lower than the normal Mn concentrations in soil. 

Trace component on the earth’s crust 

(0.008%), nickel combined with other elements 

occurs naturally in the earth's crust, is found in all 

soils, and is also emitted from volcanoes. Nickel 

compounds are used for nickel plating, to color 

ceramics, to make some batteries, and as substances 

known as catalysts to increase the rate of chemical 

reactions. Nickel may be released to the environment 

from the stacks of large furnaces used to make alloys 

or from power plants and trash incinerators. 

Soil generally contains between 4 and 80 

mg/kg dry weight nickel. The highest soil 

concentrations (up to 9.000 ppm) are found near 

industries where nickel is extracted from ore. High 

concentrations of nickel occur because dust released 

from stacks during processing settles out of the air. 

Ni conc., mg/kg d.w. 

50 

40 

30 

20 

10 

0 


month 

surface 

depth 

Fig. 6. Nickel concentration evolution in soil adjacent to 



In Eforie Sud soil samples Ni concentration 


surface samples and 15.68 – 30.95 mg/kg dry weight 

in depth samples. Soil samples from Techirghiol 

registered higher Ni concentrations (11.30 – 28.55 

mg/kg dry weight in surface samples and 15.44 – 

49.47 mg/kg dry weight in depth samples). The 

determined Ni concentrations in both analyzed soils 

sometimes exceeded the normal limit in soil. Another 

observation consists in the fact that generally nickel 

concentration is higher in depths samples than in the 

surface samples. 

Lead is a trace component in the earth’s crust; 

the average reported lead concentration in the 

lithosphere is 14 mg/kg dry weight. The most 

important environmental sources for Pb are gasoline 

combustion (presently a minor source, but in the past 

40 years a major contributor to Pb pollution), Cu–Zn– 

Pb smelting, battery factories, sewage sludge, coal 

combustion, and waste incineration. 

Lead exhibits a pronounced tendency for 

accumulation in the soil, because it is minimally 

mobile even at low pH value. High levels of lead 

pollution still occur in the vicinity of industrial 

501


facilities and waste incinerators that have insufficient 

elimination of suspended dust. 

The mean lead concentrations in studied soil 

samples are presented in the Fig. 7. 

significantly reduced. Fig. 8 presents the mean zinc 

concentration in studied soil samples. 

a) 

a) 

100 

Pb conc., mg/kg 

d.w. 

14 

12 

10 

8 

6 

4 

2 

0 


month 

surface 

depth 

Zn conc., mg/kg 

d.w. 

80 

60 

40 

20 

0 


month 

surface 

depth 

b) 

Pb conc., mg/kg d.w. 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

b) 


month 

surface 

depth 

Fig. 7. Lead concentration evolution in soil adjacent to 



In Eforie Sud soil samples Pb concentration 


surface samples and 5.98 – 11.42 mg/kg dry weight in 

depth samples. Soil samples from Techirghiol 

registered higher Pb concentrations (1.02 – 16.27 

mg/kg dry weight in surface samples and 5.05 – 17.93 

mg/kg dry weight in depth samples). 

Lead concentration is generally higher in 

depths samples than in the surface samples and all 

determined values are lower than the normal Pb 

concentrations in soil. 

Zinc is an essential element, a trace 

component in the earth’s crust (0.013%); the average 

reported Zn concentration in lithosphere is 80 mg/kg 

dry weight. Zinc occurs naturally in air, water and 

soil, but zinc concentrations are rising unnaturally, 

due to addition of zinc through human activities. 

Most zinc is added during industrial activities, such as 

mining, coal and waste combustion and steel 

processing. 

Zinc is one of the most mobile metals in the 

soil. The solubility of zinc in soil increases especially 

at pH


samples and 20.90 – 28.95 in depth samples; for lead 

between 7.24 – 8.94 in surface samples and 7.90 – 

9.08 in depth samples and for zinc between 44.55 – 

47.71 in surface samples and 44.28– 49.93 in depth 

samples. 

Except nickel all other metals concentrations 

have been founded below the normal limits from 

Romanian regulations. As a general observation, in 

depth soil concentrations are higher (Cr, Cu, Ni, Pb) 

or similar (Mn, Zn) than in surface samples. 

Cadmium and cobalt have different concentration 

evolution between depth and surface samples in 

studied locations. 

References 

Anderson K.A., (1999), Analytical Techniques for 

Inorganic Contaminants, AOAC International. 

Baiulescu G.E., Dumitrescu, P., Zugrăvescu Gh., (1990), 

Sampling, Ellis Horwood London. 

Burnley S.J., (2007), The use of chemical composition data 

in waste management planning – A case study, Waste 

Management, 27, 327-336. 

Chirila E., Draghici C., (2003), Pollutants analysis. I. Water 

Quality Control (in Romanian), Transilvania 

University Press, Brasov, Romania. 

Chirila E., (2004), Sampling, In: Colbeck I., Drăghici C., 

Perniu D., (Eds), Polution and Enviromental 

Monitoring, The Publishing House of the Romanian 

Academy, Bucharest, 109-128. 

Crompton T.R., (2001), Determination of Metals and 

Anions in Soils, Sediments and Sludges, Spon Press, 

Taylor & Francis Group. 

Dobra M., Viman V., (2006), Determination of the 

concentration of heavy metals in soils and plants by 

ICP-MS, Environmental Engineering and 

Management Journal, 5, 1197-1203. 

Draghici C., Coman Gh., Sica M., Perniu D., Tica R., 

Badea M., (2004), Capilary electrophoresis for soil 

analysis, Proceedings Bramat Brasov Romania 2003, 

494-501. 

ISO 11466 (1995) Soil quality – Extraction of trace 

elements soluble in aqua regia. 

Manea F., (2003), Solid waste management, In: Waste 

management, Pretty J., Oros V., Draghici C. (Eds), 

The Publishing House of the Romanian Academy, 

Bucharest, 87-93. 

Manea F., (2004), Soil monitoring, In: Pollution and 

Environmental Monitoring, Colbeck I, Draghici C., 

Perniu D., (Eds), The Publishing House of the 

Romanian Academy, Bucharest, 87-95. 

Schwedt G., (2001), The Essential Guide to Environmental 

Chemistry, John Wiley &Sons, Ltd. 

Statescu Fl., Cotiusca-Zauca D., (2006), Heavy metal soil 

contamination, Environmental Engineering and 


503

TECHNOPOLIS/Environmental Engineering and Management Journal, 6 (2007), 6, 504 

ENVIRONMENTAL ASSESSMENT LABORATORY 

The Environmental Assessment Laboratory was 

founded in 2006, within a project financed by the 

INFRATECH Program, administrated by the Ministry 

of Education and Research. 

The laboratory operates as a part of Tehnopolis 

Science and Technology Park Iasi – a consortium 

having our Technical University “Gh. Asachi “ of Iasi 

as partner. 

The laboratory is staffed by some members of the 

Environmental Engineering and Management 

Department of the Faculty of Chemical Engineering 

and Environmental Protection (Technical University 

“Gh. Asachi “of Iasi). 

With a rich expertise in environmental engineering 

and management, the staff is especially competent in: 

• Environmental monitoring 

o Specialized in complex 

environmental analysis such as the 

identification and quantification of 

organic pollutants (VOC, POPs, 

pesticides, PCBs etc.) from air, 

water and soil; 

• Environmental impact assessment; 

• Risk assessment 

• Environmental consulting (Environmental 

permitting, Quality management certification 

for ISO 14.001, Emission reduction plan for 

VOC; Solvent management plan); 

The research activity of the group members is 

illustrated by: 

• More than 100 scientific articles, published 

in well-known national and international 

(ISI); 

• More than 45 national and international 

patents; 

• Books published in Romania (publishers 

accredited by CNCSIS) and abroad; 

• PhD thesis approaching new and original 

topics in environmental engineering and 

management; 

• Centers of excellence in research 

• International collaborations (within 

programs such as PHARE, EcoLinks, or 

financed by German Ministry for Education 

and Research, Swiss Science Foundation, 

Swedish Institute Stockholm etc) 

During the last decade of activity, the members of the 

laboratory have participated in more than 200 

research contracts with the industry, on different 

activities: 

• Environmental permitting; 

• Integrated pollution prevention and control; 

• Technical Inspection Certificates for VOC 

(according to H.G. 568/2001), being one of 

the six accredited laboratories in the 

country); 

• VOC emission reduction schemes (H.G. 

699/2003) 

• Other projects concerning the cleaning or 

depollution of different industrial effluents 

and streams. 

Facilities and Equipments 

The laboratory is being organized according to the 

requirements of the Quality management system ISO 

/IEC 17025:2000 “General requirements regarding 

the competence of the testing and calibration 

laboratories”. 

The main equipments used in the laboratory, fully 

compliant with international standard methods, are: 

• High resolution GC-MS with 

hyperbolic quadrupole mass 

analyzer (Agilent) 

• Thermal desorber (Markes 

International) 

• High precision analytical balances 

• Ovens, automatic pipettes etc 

In addition to the classical GC-MS/FID methods, our 

laboratory is especially interested in using the 

analytical thermal desorption methods for the 

measurement of trace level volatile and semi-volatile 

organic chemicals (VOCs and SVOCs). It is the 

technique of choice for air monitoring (indoor, 

outdoor, workplace, automobile interior, breath, etc.) 

and is an invaluable tool for the analysis of soil, 

polymers, packaging materials, foods, flavors, 

cosmetics, tobacco, building materials, 

pharmaceuticals, and consumer products. Indeed, 

virtually any sample containing volatile organic 

compounds can be analyzed using some variation of 

this technique. 

In this context, we are opened for collaboration with 

scientific institutions in the areas covered by our 

laboratory. 

Cezar Catrinescu 



Faculty of Chemical Engineering 


504




______________________________________________________________________________________________ 

POLYELECTROLYTE – SURFACTANT COMPLEXES 

Mihaela Mihai ∗ , Gabriel Dabija, Cristina Costache 

Polytechnica University Bucharest, Faculty of Applied Chemistry and Materials Science, 1 – 7 Polizu Street, Sector 1, 011061 

Bucharest, Romania 

Abstract 

The formation of the polyelectrolyte – surfactant complexes has been studied. On this purpose has been measured the critical 

micelle concentration for every polyelectrolyte and surfactant which had been used. The phase behaviour of mixtures of a cationic 

polyelectrolyte (Praestol 611) and an anionic surfactant (sodium lauryl sulphate – SLS) has been studied. For a given 

polyelectrolyte concentration, with increasing surfactant concentration, three phase regions were identified. The first region is a 

single homogeneous phase. Within this region, at some surfactant concentration, above the critical aggregation concentration 

(cac), stable open – network ‘particles’ form, typically 100 nm in size, which are net positively charged. However, as the 

surfactant concentration is increased further, these particles aggregate and form a two – phase system: a separated gel phase, 

containing a high percentage of water co-existing with an aqueous surfactant phase. The rheological consequences of interactions 

of polyelectrolytes with surfactants of the opposite charge are experimentally studied. 

Key words: polyelectrolyte, surfactant, complex polyelectrolyte – surfactant, rheologie 


Polyelectrolytes are used in a number of 

technical applications, such as water treatment. With 

polyelectrolytes can change the surface properties of 

colloids, rheology of solutions, wettability etc. In 

particular, cationic polyelectrolytes are used in the 

water treatment because of their ability to interact 

with negatively charged surfaces. Using surfactants in 

combination with polyelectrolytes increases the width 

of the applications even further, and mixtures of 

polymers and surfactants in aqueous solution have 

been used for colloidal stabilization or flocculation as 

well as rheology control. 

The interaction between polyelectrolytes and 

oppositely charged surfactants can be understood 

considering electrostatic and hydrophobic interactions 

(Vautrin, 2006). At low concentrations, the surfactant 

binds individually to the polyelectrolyte through 

electrostatic interactions. A cooperative association 

occurs at the critical aggregation concentration, cac, 

as the concentration is raised due to hydrophobic 

interactions between the surfactant tails. This 

aggregation process leads in some cases to a beadand-necklace 

type structure, where surfactant 

aggregates are located along the polyelectrolyte chain 

(Bastardo, 2005). 

The addition of a simple salt lowers the 

viscosity of polyelectrolyte solutions because salt 

screens the electrostatic repulsion that expands the 

size of the polyelectrolyte. The addition of an 

equivalent amount of oppositely charged surfactant 

has a larger effect on viscosity (Abuin and Scaiano, 

1986). This is because flexible polyelectrolytes bind 

to the spherical surfactant micelles by wrapping 

around the exterior of the micelle, thereby shortening 

the effective length of the polyelectrolyte chain 

(Konop, 1997). The polyelectrolyte stabilizes the 

large charge on the micelle surface and no counterion 

condensation on the micelle surface is needed 

(Goddard, 1993). These effects stabilize the spherical 

micelles, reflected in micelles forming at a much 

lower concentration when oppositely charged 

polyelectrolytes are present (Colby, 2000). 


The cationic Praestol 611 is a commercial 

denomination of a copolymer of polyacryl amide with 

acrylic acid. The association between the cationic 

∗ Author to whom all correspondence should be addressed: mihai_mihaela2007@yahoo.com

Mihai et al. /Environmental Engineering and Management Journal 6 (2007), 6, 505-509 

polyelectrolyte Praestol 611 and the anionic 

surfactant sodium lauryl sulphate (SLS) has been 

studied using the surface tension measurements of the 

solutions. These are simple measurements that 

monitor the polyelectrolyte and surfactant aggregates 

formed in solution. 

The rheological study is experimentally 

studied with cylinder – cylinder rheoviscosimetre 

Rheotest RV. 

3. Results and Discussion 

σ, mN/m 2 

100 

90 

80 

70 

60 

50 

40 

30 

complex solution between 

Praestol 611 c = 7.5 10 -4 and SLS c SLS = 4.210 -3 

SLS solution 

The consequences of interactions of 

polyelectrolytes with surfactants of the opposite 

charge are presented in Figs 1 – 6. 

From the diagrame analysis of those Figures 

results that for c SLS < 10 -5 % there are polymer – 

surfactant associations, which significantely reduce 

the superficial tension of the solution. 

At these concentrations neither the polymer 

nor the surfactant are associated in miceles. It results 

that the surfactant molecules jointo the polymer – 

macromolecule and both form associations, based on 

electrostatic attraction forces. For c SLS > 10 -4 % the 

surfactant molecules are associated in miceles but the 

macromolecules of polymer are not associated and 

the complex forms by engraftment of surfactant 

miceles on the macromolecules polymer. The 

complex solution superficial tension is lower then the 

one of the polymer solution. This properties 

recomend the use of this solution in interfacial liquid 

– solid processes. The same results are obtained at 

higher concentration of the polymer solution, while 

this concentration is lower then the micelar critical 

concentration. 

20 

10 

c cm 

1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1 

c SLS 

Fig. 2. Superficial tension dependence for the aqueous 

concentration solutions of the Praestol 611, c = 7.5 10 -4 % 

and SLS complex for c = 4.2 10 -3 % SLS concentration 

solution at 20 °C 

σ, mN/m 2 

100 

80 

60 

c ca 

c cs 

Praestol 611 c = 1.2 10 -4 and SLS complex solutions 

40 c = 1.0 10 -5 % 

c = 5.0 10 -5 % 

c = 1.0 10 -4 % 

20 c = 4.2 10 -3 % 

c = 1.0 10 -2 % 

SLS solution 

0 

1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 

c SLS , % 

90 

80 

Praestol 611, c = 7.5 10 -4 and SLS complex solutions 


concentration solutions of the Praestol 611 and SLS 

complex for different SLS concentration solutions at 20 °C 

σ, mN/m 2 

c = 1.0 10 -5 

70 

c SLS 

c = 5.0 10 -5 

60 

c = 1.0 10 -4 

50 

c = 4.2 10 -3 

c = 1.0 10 -2 

40 

c = 4.2 10 -2 

30 

20 

10 

1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1 1 10 100 


concentration solutions of the Praestol 611 and SLS 

complex for different SLS concentration solutions at 20 °C 

σ, mN/m 2 

100 

80 

60 

40 

20 

0 

Praestol 611 c = 1.6 10 -3 and SLS solutions 

c = 1.0 10 -5 % 

c = 5.0 10 -5 % 

c = 1.0 10 -4 % 

c = 4.2 10 -3 % 

c = 1.0 10 -2 % 

solutie SLS 

1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 

c SLS , % 

Fig. 4. Superficial tension dependence for the 

aqueous concentration solutions of the Praestol 611 

and SLS complex for different SLS concentration 

solutions at 20 °C 

506


At concentrations c > 10 -2 of the polymer 

solution the formed complex precipitates entering in 

the heterogeneous zone of complex formation. In the 

analysed situations the concentrations for aggregation 

and critical concentration of saturation have the same 

values for every experiment, c ca = 4·10 -4 %, and c cs = 

4·10 -3 %. 

The results of the measurements of the 

rheological study of complex solutions are presented 

in Figs 5 – 8. Fig. 5 shows that the Praestol 611 

solution has the Bingham pseudoplastic behaviour 

0, 46 

and the rheological model isτ 

= 235,71+ 

138,44 & γ . 

10 4 

10 3 

10 2 

10 1 

10 0 

10 -1 

Praestol 611 c = 0.1 and SLS c = 7.0 10 -4 

complex solution 

τ = f(γ) 

η = f(γ) 

10 5 γ, s -1 

6x10 3 

Solution of Praestol 611 c = 0,01% 

10 -2 

1 10 100 1000 

5x10 3 

a. 

τ, N/m 2 

4x10 3 

3x10 3 

2x10 3 

1x10 3 

going 

return 

Equation: y = a + b*x^c 

a 235.71 

b 138.44 

c 0.46 

0 

0 200 400 600 800 1000 1200 1400 

a. 

γ, s -1 



10 5 

10 4 

10 3 

10 2 

10 1 

10 0 

10 -1 

τ = f (γ) 

η = f(γ) 

Solution of Praestol 611 c = 0,01% 

10 -2 

10 100 1000 

γ, s -1 

100 

b. 

η, cP 

10 

going 

return 

1 

1 10 100 1000 

γ, s -1 

Fig. 6. Rheograme of complex solution made with Praestol 

611 c = 0.01% and SLS concentrations solutions c = 7 10 -4 

% (a) and c = 1.2 10 -3 % (b) 

The repetition of the experiment at the 

increase and decrease of the share rate is presented in 

Figs 8 – 9. The rheogrames show that under share 

stress the structure of the polymer surfactant complex 

restructures. 

b. 

Fig. 5. Rheograme of Praestol 611 c = 0.01 % solution at 20 

°C in coordonate τ = f(γ) (a) and η = f(γ) (b) 

The surfactant admixture in polymer solution 

in low quantities (Fig. 6a) significantly modifies the 

rheogram of the polymer solution (the value of 

apparent viscosity lowers and for a certain value of 

share rate it raises). The same effect but amplified can 

be observed for admixture of greater quantities of 

surfactant (Figs 6a, 7a and 7b). 


The interaction between polyelectrolytes and 

oppositely charged surfactants are experimentally 

studied. At low concentrations, the surfactant binds 

individually to the polyelectrolyte through 

electrostatic interactions. A cooperative association 

occurs at the critical aggregation concentration, c ac , 

when the surfactant aggregates are located along the 

polyelectrolyte chain. 

507

Mihai et al. /Environmental Engineering and Management Journal 6 (2007), 6, 505-509 



10 6 

10 5 

a. 



10 4 

10 4 

10 3 

10 2 

10 1 

τ = f(γ) 

η = f(γ) 

η, cP 

10 3 

10 2 

10 1 

10 0 

10 -1 

10 -2 

1 10 100 1000 

γ, s -1 

a. 



10 5 

10 0 

10 -1 

1 10 100 1000 

b. 

going 

return 

γ, s -1 

Fig. 8. Rheograme of complex solution (Praestol 611 c = 

0.01 % and SLS c = 1.6 10 -3 %) in coordonate τ = f(γ) (a) 

and η = f(γ) (b). 

10 4 

10 3 

10 2 

τ = f(γ) 

η = f(γ) 



10 6 

10 5 

10 1 

10 0 

10 -1 

10 -2 

1 10 100 

b. 

γ, s -1 

Fig. 7. Rheograme of complex solution made with Praestol 

611 c = 0.01 % 



10 5 

10 4 

η, cP 

τ, N/m 2 

10 4 

10 3 

10 2 

10 1 

10 0 

1000 

100 

10 

1 10 100 1000 

a. 

going 

return 

γ, s -1 



τ, N/m 2 

10 3 

10 2 

going 

10 1 

return 

10 0 

1 10 100 1000 

γ, s -1 

1 

0.1 

going 

return 

γ, s -1 

1 10 100 

b. 

Fig. 9. Rheograme of complex solution (Praestol 611 c = 

0.01% and SLS c = 2,3 10 -3 %) in coordonate τ = f(γ) (a) 

and η = f(γ) (b) 

508


The rheology of polyelectrolyte solutions are 

profoundly altered by the presence of surfactants. The 

addition of an oppositely charged surfactant lowers 

the viscosity of polyelectrolyte solutions. This is 

because flexible polyelectrolytes bind to the spherical 

surfactant micelles by wrapping around the exterior 

of the micelle. 

References 

Abuin E. B., Scaiano J. C., (1984), Exploratory study of the 

effect of polyelectrolyte surfactant aggregates on 

photochemical behavior, J. Amer. Chem. Soc., 106, 

6274-6283. 

Bastardo L. A., (2005), Self assembly of Surfactants and 

Polyelectrolytes in Solutions at Interfaces, 

PhD.Thesis at the Royal Institute of Technology 

Stockholm. 

Colby R., (2000), Polyelectrolyte interactions with 

surfactants and proteins, XIIIth International 

Congress on Rheology, Cambridge, UK, 414-416. 

Goddard E. D., Ananthapadmanabhan K. P., (1993), 

Interaction of Surfactants with Polymers and 

Proteins, CRC Press, London. 

Konop A. J., (1997), Polyelectrolyte Collapse Induced by 

Aggregation of Oppositely Charged Surfactant, 

Masters Thesis, Pennsylvania State University. 

Konop A.J, Colby R. H., (1999), Role of condensed 

counterions in the thermodynamics of surfactant 

micelle formation with and without oppositely 

charged polyelectrolytes, Langmuir 15, 58-65. 

Vautrin C., (2006), Stabilité et Structure d’Agrégats 

Catanioniques, PhD.Thesis University Versailles 

Saint-Quentin-en-Yvelines, France. 

509

PLATFORM/Environmental Engineering and Management Journal, 6 (2007), 6, 510 

INTERDISCIPLINARY TRAINING AND RESEARCH PLATFORM 

HIGH PERFORMANCE MULTIFUNCTIONAL POLYMERIC MATERIALS 

FOR MEDICINE, PHARMACY, MICROELECTRONICS, 

ENERGY/INFORMATION STORAGE, ENVIRONMENTAL PROTECTION 

The Platform aims to develop training and 

interdisciplinary research in high-performance 

multifunctional polymeric materials. The nucleus of 

the Platform is based on the Center of Excellence 

POLYMERS, officially accredited by CNCSIS 

(7.06.2003), center acting within the “Gh. Asachi” 

Technical University of Iasi. The Platform will be 

integrated in national/European networks and will 

ensure the training and improvement of human 

resources through high education and research, will 

enhance the research performance and the visibility of 

Romania, will contribute to Romanian high education 

and research integration in European Education Area 

and European Research Area, to the development of 

the knowledge-based society and will increase the 

socio-economic impact of research. 

To ensure the success of the Project, a set of 

specific objectives has been defined: 

• New educational programmes, oriented towards 

European priorities, able to ensure highly qualified 

human resources and to integrate them into the 

knowledge-based modern society 

• New contents, forms and methods of training, 

specific for the development of education and 

research in multifunctional polymeric materials and 

in agreement with Lisbon Agenda and with 

Bologna Process, as well as with Romanian 

priorities 

• Elaboration and implementation of 

interdisciplinary programmes of training (master, 

doctoral, post-doc) 

• Consolidation of excellence in research in the field 

of high performance multifunctional materials by 

promoting interdisciplinary programmes and by 

attracting the most talented graduates – from 

Romania and abroad – for PhD and post-doc 

studies 

• Extension and consolidation of the research 

infrastructure (hard equipment) of the Platform, to 

improve the training and research process, in order 

to increase Platform competitiveness in accessing 

national (CNCSIS, CEEX, PNCDI 2) and 

international (FP7, NATO, NSF etc.) programmes 

and the efficiency in answering the requirements of 

the regional, national and European economic areas 

• Strengthening the scientific cooperation with 

academic and economic partners at national and 

European level 

• Promoting the exchange of information and 

communication between the academic and socioeconomic 

environments, to consolidate the 

knowledge-based society and to accelerate the 

integration of Romania into the European Union. 

The Project will develop (i) education activities 

through (i-a) master studies (two directions are 

proposed – Biomaterials – addressed to graduates of 

510 

chemistry, chemical engineering, medical 

bioengineering, biology, medicine, pharmacy – and 

Multifunctional Materials for Advanced 

Technologies, addressed to graduates of chemistry, 

chemical engineering, medical bioengineering, physics, 

electronics and electrical engineering, civil engineering, 

environment protection; both master programmes will 

be in Romanian and/or English), (i-b) doctoral studies 

with a pronounced interdisciplinary character and 

implemented within the “co-tutelle” system, (i-c) postdoc 

studies (financed from other programmes), and (ii) 

research activities developed within five programmes, 

i.e., (ii-a) Biomaterials. Polymer-drug Systems with 

Controlled and Targeted Release (polymer-drug 

conjugates, diffusional systems, drug inclusion in 

polymeric micro- or nanoparticles), (ii-b) Smart 

Multifunctional Polymeric Materials (molecular 

imprinting, diagnostics and bioseparation, nanocapsules 

and nanostructured membranes via core-shell particles, 

smart hydrogels and nanostructured gels, biomimetic 

polymeric networks, nanofabrication), (ii-c) Motile 

Molecular Systems (hybrid and organic polymers for 

biology, microelectronics, nanorobotics and 

energy/information storage), (ii-d) Liquid Crystal 

Hetero-organic and Organic Compounds (liquid 

crystals for displays, opto-electronic devices, ferroelectric 

liquid crystals), (ii-e) Molecular Modeling and 

Artificial Intelligence (conformational analysis and 

simulation of properties, neuronal networks, fuzzy 

systems). All planned activities and actions are based 

on a deep analysis of the tendencies in the 

interdisciplinary education and research, on the 

requirements of the national and European market. 

Most of Platform budget is dedicated to the serious 

improving of the research infrastructure (hard 

equipments). Additional funding and expertise will be 

obtained through the facilities offered by the “Gh. 

Asachi” Technical University of Iasi, the infrastructure 

and human resources of the POLYMER Centre of 

Excellence, through the facilities offered by the 

traditional national and European partners of the 

Platform. Platform sustainability will be ensured by 

different funding attracting activities – training of 

specialists from SMSs, consulting activities, national 

and international grants, the RENAR accredited 

laboratories, the Technology Transfer Center and the 

Innovation Relay Centre established within the 

Platform, the specific activities to be performed within 

the Science and Technology Park in Iasi. 

The benefits of the Platform will cover the 

whole high education and research environment in Iasi 

and in the North-Eastern Region of Romania and all 

Platform partners – both academic and economic. 

Constanţa Ibănescu 

Department of Natural and Synthetic Polymers 

Faculty of Chemical Engineering, 

“Gh. Asachi” Technical University of Iasi, Romania




_____________________________________________________________________________________________ 

MODELLING OF SORPTION EQUILIBRIUM OF Cr(VI) ON 

ISOMORPHIC SUBSTITUTED Mg/Zn-Al – TYPE HYDROTALCITES 

Laura Cocheci 1∗ , Aurel Iovi 1 , Rodica Pode 1 , Eveline Popovici 2 

1 

“Politehnica” University of Timisoara, Faculty of Industrial Chemistry and Environmental Engineering, 2 Victoriei Sq., 300006 

Timisoara, Romania 

2 “Al. I. Cuza” University of Iasi, Faculty of Chemistry, 11 Copou Blvd., 700506 Iasi, Romania 

Abstract 

This paper dealt with Cr(VI) sorption on isomorphic substituted Mg/Zn-Al – type hydrotalcites under proper working conditions. 

The prepared samples were named Mg 3 Al, Mg 2 ZnAl, Mg 1.5 Zn 1.5 Al, MgZn 2 Al and Zn 3 Al. The experimental data concerning 

sorption isotherms were modelled in accordance with four equilibrium equations: Langmuir (L), Freundlich (F), Langmuir- 

Freundlich (L-F) and Redlich-Peterson (R-P) by using two ways: (i) estimation of q max , K and n; and (ii) estimation of K and n, 

for q max values equal to the experimental maximum uptake value. It was proved that Langmuir-Freundlich model was the best 

solution for fitting the experimental data. The results also allowed setting up a ranking order of the sorption capacities for the 

studied hydrotalcites. 

Key words: equilibrium modelling, hydrotalcites, hexavalent chromium sorption 


Chromium compounds are used in various 

industries (e.g. textile dying, tanneries, metallurgy, 

metal electroplating and wood preserving); hence, 

large quantities of chromium have been discharged 

into the environment due to improper disposal and 

leakage (Gheju and Iovi, 2006). 

The toxicity of chromium strongly depends on 

its oxidation state. Although Cr(III) is an essential 

dietary nutrient, it can be toxic in high doses. Cr(VI) 

has also been associated with increased incidents of 

cancers. The different bioavailability and bioactivity 

between the trivalent and hexavalent species might 

account for the differences in toxicity (Toxicological 

Profile of Chromium, 1998). 

Several methods are available for chromium 

ions removal: chemical reduction followed by 

precipitation, sorption, electrochemical treatment, 

membrane separation processes and bioremediation. 

Sorption is one of the most popular methods 

for the removal of chromium from wastewaters. The 

pollutant adsorbs onto the solid adsorbent surface 

from the effluent with the quantity of the removed 

pollutant depending on the adsorption capacity of the 

sorbent. 

Layered double hydroxides (LDHs), also 

called hydrotalcite-like compounds, constitute a class 

of lamellar ionic compounds containing a positively 

charged layer and exchangeable anions within 

interlayer. The chemical composition of LDHs can be 

represented by the general formula [M II 1-x M III x 

(OH) 2 ] x+ [A n- x/n . mH 2 O] x- , shortly noted [M II R – M III – 

A] with R = (1-x)/x , where M II is a divalent cation, 

M III a trivalent cation and A n- charge compensating 

anions. M II /M III molar ratios (denoted R) between 1 

and 5 are possible (Kooli et al., 1997; Miyata, 1975). 

Carbonates are the interlayer anions in the naturally 

occurring mineral hydrotalcite, which is a member of 

this class of materials. The decomposition of Mg 3 Al – 

CO 3 LDH when heated at around 500 °C leads to 

mixed metal oxides, which are characterized by high 

specific surface areas and homogeneous dispersion of 

metal cations. The mixed metal oxides can take up 

anions from aqueous solution, with concomitant 

reconstruction of the original layered structure, as 

expressed by the equations (1) and (2) (Lv et al., 

2006): 

∗ Author to whom all correspondence should be addressed: laura.cocheci@chim.upt.ro

Cocheci et al. /Environmental Engineering and Management Journal 6 (2007), 6, 511-515 

Mg 1-x Al x (OH) 2 (CO 3 ) x/2 . mH 2 O 

⎯ °C 

500 ⎯ → 

Mg 1-x Al x O 1+x/2 + x/2CO 2 + (m+1)H 2 O (1) 

Mg 1-x Al x O 1+x/2 +(x/n)A n- +(m+1+(x/2)+y)H 2 O ⎯ ⎯→ 

Mg 1-x Al x (OH) 2 (A n- ) x/2 . mH 2 O + xOH - (2) 

Therefore, the calcined layered double 

hydroxides can be used as potential ion 

exchangers/adsorbents for removal of toxic anions 

from wastewaters. 

This paper focuses on the study of equilibrium 

removal of chromate ions by isomorphic substituted 

Mg/Zn-Al – type hydrotalcites. Four equilibrium 

models are used to fit the experimental data: 

Langmuir (L), Freundlich (F), Langmuir-Freundlich 

(L-F) and Redlich-Peterson (R-P). 


Five formulations having various Mg/Zn ratios 

were obtained from the corresponding nitrates by 

using the co-precipitation method under low 

oversaturation (Vaccari, 1998). The five materials 

were named as follows: Mg 3 Al, Mg 2 ZnAl, 

Mg 1.5 Zn 1.5 Al, MgZn 2 Al and Zn 3 Al. 

The fractions lower than 0.080 mm were used 

as adsorbent. The samples activation was performed 

in an oven, at temperatures of 500°C in air, at a rate 

of 5°C/min for 4 hours. The calcined products were 

kept in a desiccator over fused CaCl 2 in order to avoid 

adsorption of CO 2 and moisture from the atmosphere. 

All sorption experiments were performed on 

activated Mg/Zn-Al hydrotalcite samples. Conic 

flasks of 100 ml were used to contact 50 mL K 2 Cr 2 O 7 

solutions containing Cr(VI) from 5 to 50 mg/L with 

the hydrotalcite samples corresponding to a solid : 

liquid ratio of 1g/L. The initial pH was adjusted to 7 ± 

0.2 by a minimum addition of NaOH 0.1 M. Under 

these circumstances, Cr(VI) occurred as chromate 

ions. The pH before and after sorption experiments 

was checked by using an Inolab pH meter. The use of 

a pH buffer was avoided to restrict the addition of 

foreign anions. For the same reason, the flasks were 

hermetically sealed during experiments. The 

chromium removal was conducted batchwise in an 

orbital shaker model GFL 3017, at 20±2 °C, in order 

to reach the sorption equilibrium for 10 hours. 

At equilibrium, the solid was separated by 

filtration. Cr(VI) concentration in aqueous solution 

was spectrophotometrically determined at 540 nm by 

means of diphenylcarbazide colorimetric method 

(Eaton et al., 2005). Replicate measurements on 

Cr(VI) samples showed that relative precisions of less 

than 2% could be routinely obtained. 

Chromium uptake by the sorbent was 

calculated by using the Eq. (3): 

where q e is the sorption loading of sorbent material at 

equilibrium (mg/g), V the volume of solution (L), C 0 

(mg/L) and C e (mg/L) the initial and equilibrium 

concentrations of Cr(VI), respectively, and m is the 

mass of adsorbent (g). 

The experimental data were processed by 

using four mathematical models: Langmuir (L), 

Freundlich (F), Langmuir-Freundlich (L-F) and 

Redlich-Petereson (R-P) to assess which of the 

proposed models described the sorption equilibrium 

to the best. 


The four mathematical expressions used for 

the fits are given in Table 1. 

Table 1. The mathematical expressions of the isotherms 

used for the modelling of the sorption experiments 

Model 

Equation 

Langmuir (L) 

KL 

⋅Ce 

qe 

= qmax 

1+ 

KL 

⋅Ce 

Freundlich (F) 

1/ n 

qe 

= KF 

⋅Ce 

Langmuir- 

n 

( K 

Freundlich (L-F) 

LF ⋅Ce) 

qe 

= qmax 

n 

1+ 

( KLF 

⋅Ce) 

Redlich- 

KRP 

⋅Ce 

Peterson (R-P) qe 

= qmax 

n 

1+ 

( KRP 

⋅Ce) 

q e is the sorption loading of sorbent material at equilibrium (mg/g); 

C e the equilibrium concentration of Cr(VI) (mg/L); q max maximum 

sorbed quantity (mg/g); n is the non-homogeneity factor; K – 

constant) 

The four mathematical models were chosen 

because other published papers reported the 

preponderant use of Langmuir and Freundlich 

equations, which can be changed into linear forms 

easily, to process the results from anion sorption 

equilibria on these kinds of materials (Das et al., 

2003; Das et al., 2004; Ferreira et al., 2006; Lazaridis 

and Asouhidou, 2003; Lv et al., 2006). Some papers 

compared the two models to the Langmuir-Freundlich 

model (Lazaridis, 2003), and others mentioned the 

use of Redlich-Peterson model to assess anion 

sorption equilibria on these kinds of materials 

(Lazaridis et al., 2002). Moreover, despite the 

linearization resulted from the Langmuir model 

(Fig.1), R 2 coefficients showing very good correlation 

(0.9996, 0.9972, 0.9992, 0.9968 and 0.9896 for 

Mg 3 Al, Mg 2 ZnAl, Mg 1.5 Zn 1.5 Al, MgZn 2 Al and Zn 3 Al 

respectively), when the experimental results were 

fitted in the Langmuir equation, the R 2 coefficients 

were very low. Two types of calculation were 

performed by using the four equilibrium equations: (i) 

estimation of q max , K and n; and (ii) estimation of K 

and n, for q max values equal to the experimental 

maximum uptake value. 

q e = (C 0 – C e ) V/m (3) 

512

Modelling of sorption equilibrium of Cr(VI) on isomporphic substituted Mg/Zn-Al-type hydrotalcites 

C e 

/ q e 

[g/L] 

0.5 

0.4 

0.3 

0.2 

The comparison showed lower R 2 coefficients 

for the second calculation type. This finding 

demonstrated that the increase of the number of 

assessed parameters decreased the computation error. 

40 

30 

0.1 

0.0 

0 5 10 15 

C e 

[mg/L] 

Fig. 1. Linear fit of experimental data by using Langmuir 

model for Mg 3 Al sample 

The values of the parameters and the estimate 

of the goodness of the fit for each model are given in 

Table 2. Figures 2–5 compare the plots resulted by 

fitting experimental data for Mg 3 Al sample by using 

the four equilibrium equations. 

40 

q e 

[mg/g] 

20 

10 

0 

0 5 10 15 

C e 

[mg/L] 

exp 

K, n, q max 

est 

K, n est 

Fig. 4. Modelling of Cr(VI) sorption behaviour on Mg 3 Al 

sample by using Langmuir-Freundlich equation 

40 

30 

30 

q e 

[mg/g] 

20 

10 

exp 

K, q max 

est 

K est 

q e 

[mg/g] 

20 

10 

exp 

K, n, q max 

est 

K, n est 

0 

0 5 10 15 

C e 

[mg/L] 

0 

0 5 10 15 

C e 

[mg/L] 


sample by using Langmuir equation 

q e 

[mg/g] 

40 

30 

20 

10 

0 

0 5 10 15 

C e 

[mg/L] 

exp 

K, n est 


sample by using Freundlich equation 


sample by using Redlich-Peterson equation 

Langmuir, Freundlich and Redlich-Peterson 

models showed that the calculated sorption capacities 

q max were higher than those resulted from 

experiments. This was most probably due to the fact 

that the initial chromium concentrations used in the 

experimental studies were not enough to achieve total 

sorbent saturation. For the Redlich-Peterson model, 

the calculated non-homogeneity index n was close to 

1, which reduced the Redlich-Peterson equation to the 

Langmuir one. 

For all situations, Langmuir-Freundlich 

equation showed the best R 2 coefficients. The 

comparison of the experimental and calculated values 

and the observation of data indicated that the 

Langmuir-Freundlich model provided the best 

accurate description of the equilibrium data over the 

studied samples and concentration range. 

513

Cocheci et al. /Environmental Engineering and Management Journal 6 (2007), 6, 511-515 

Table 2. Isotherm parameters obtained by fitting of the experimental data for the sorption of Cr(VI) on isomorphic substituted 

Mg/Zn-Al – hydrotalcites 

Model 

Estimation of q max , K and n 

Estimation of K and n 

q max K n R 2 K n R 2 

Mg 3 Al 

q max = 35.43 mg/g 

Langmuir 33.65 18.54 - 0.5408 14.10 - 0.5332 

Freundlich - 29.69 14.80 0.7434 - - - 

Langmuir-Freundlich 35.76 28.17 0.55 0.8622 27.55 0.58 0.8617 

Redlich-Peterson 29.45 29.79 0.97 0.5424 15.56 1 0.5392 

Mg 2 ZnAl 

q max = 17.49 mg/g 

Langmuir 16.29 17.29 - 0.9086 13.46 - 0.8765 

Freundlich - 12.98 11.79 0.9585 - - - 


Redlich-Peterson 9.85 106.84 0.93 0.9288 14.72 0.99 0.9001 

Mg 1.5 Zn 1.5 Al 

q max = 16.17 mg/g 

Langmuir 15.67 5.01 - 0.8931 4.27 - 0.8878 

Freundlich - 11.94 10.56 0.9497 - - - 


Redlich-Peterson 11.70 12.98 0.94 0.9007 4.52 1.01 0.8912 

MgZn 2 Al 

q max = 15.25 mg/g 

Langmuir 14.22 13.51 - 0.8551 9.89 - 0.8223 

Freundlich - 11.46 12.71 0.9140 - - - 


Redlich-Peterson 5.18 245 0.92 0.8766 11.02 1.01 0.8475 

q e 

[mg/g] 

40 

30 

20 

10 

0 

0 10 20 30 40 50 

C e 

[mg/L] 

Mg 3 

Al 

Mg 2 

ZnAl 

Mg 1.5 

Zn 1.5 

Al 

MgZn 2 

Al 

Zn 3 

Al 

Fig. 6. Sorption isotherms for samples fitted in Langmuir- 

Freundlich model 

By analyzing data from Table 2 and Fig. 6, 

one can note that for Mg/Zn samples the maximum 

sorption capacities were close. Zn 3 Al sample showed 

a low sorption capacity under the working conditions 

while Mg 3 Al sample had a maximum sorption 

capacity of 35.76 mg/g, representing 71.5 % of the 

initial Cr(VI) amount, which was in accordance with 

previous reports (Das et al., 2004; Forano, 2004). 


This paper aimed at characterizing sorption 

equilibrium of Cr(VI) on five isomorphic substituted 

Mg/Zn-Al – type hydrotalcites. Four mathematical 

models and two kinds of assessment were used to 

describe the sorption equilibrium . 

The three-parametered Langmuir-Freundlich 

model approximated the experimental data over the 

concentration range to the best. 

The sorption of Cr(VI) on the investigated 

hydrotalcites showed continuous decrease of the 

sorption capacity in the following order: Mg 3 Al > 

Mg 2 ZnAl > Mg 1.5 Zn 1.5 Al > MgZn 2 Al > Zn 3 Al. 


The results are obtained as part of the Project CEEX 

No. 1/S1 – 2005 activities, under the auspices of 

MATNANTECH Scientific Authority. The authors wish to 

thank the MATNANTECH for supporting this research. 

References 

Das D.P., Das J., Parida K., (2003), Physicochemical 

characterization and adsorption behavior of calcined 

Zn/Al hydrotalcite-like compound (HTlc) towards 

removal of fluoride from aqueous solution, J. Colloid 

Interf. Sci., 261, 213-220. 

Das N.N., Konar J., Mohanta M.K., Srivastava S.C., (2004), 

Adsorption of Cr(VI) and Se(IV) from their aqueous 

solutions onto Zr 4+ -substituted ZnAl/MgAl-layered 

double hydroxides: effect of Zr 4+ substitution in the 

layer, J. Colloid Interf. Sci., 270, 1-8. 

Eaton A.D., Clesceri L.S., Rice E.W., Greenberg A.E. 

(Eds.), (2005), Standard Methods for the Examination 

of Water and Wastewater, 21 th Edition, American 

Public Health Association, Washington, DC. 

Ferreira O.P., de Morales S.G., Duran N., Cornejo L., Alves 

O.L., (2006), Evaluation of boron removal from water 

by hydrotalcite-like compounds, Chemosphere, 62, 

80-88; 

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Modelling of sorption equilibrium of Cr(VI) on isomporphic substituted Mg/Zn-Al-type hydrotalcites 

Forano C., (2004), Environmental Remediation Involving 

Layered Double Hidroxides, In: Clay Surfaces. 

Fundamentals and Applications, Wypych F., 

Satynarayana K. G. (Eds.), Elsevier, New York. 

Gheju M., Iovi A., (2006), Kinetics of hexavalent 

chromium reduction by scrap iron, J. Haz. Mat., 

B135, 66-73. 

Kooli F., Depege C., Ennaqadi A., de Roy A, Besse J.P., 

(1997), Rehydration of Zn–Al layered double 

hydroxides, Clays Clay Miner., 45, 92-98; 

Lazaridis N.K., Hourzemanoglou A., Matis K.A., (2002), 

Flotation of metal-loaded clay anion exchangers. Part 

II: the case of arsenates, Chemosphere, 47, 319-324. 

Lazaridis N.K., Asouhidou D.D., (2003), Kinetics of 

sorptive removal of chromium (VI) from aqueous 

solutions by calcined Mg-Al-CO 3 hydrotalcite, Water 

Res., 37, 2875-2882. 

Lazaridis N.K., (2003), Sorption removal of anions and 

cations in single batch systems by uncalcined and 

calcined Mg-Al-CO 3 hydrotalcite, Water, Air, Soil 

Poll., 146, 127-139. 

LeVan M.D., Carta G., Yon C.M., (1999), Adsorption and 

ion exchange, In: Green D.W. Perry’s chemical 

engineer’s handbook, 7 th Edition, McGraw-Hill, New 

York. 

Lv L., He J., Wei M., Evans D.G., Duan X., (2006), Uptake 

of chloride ion from aqueous solution by calcined 

layered double hydroxides: Equilibrium and kinetic 

studies, Water Res., 40, 735-743. 

Lv L., He J., Wei M., Evans D.G., Duan X., (2006), Factors 

influencing the removal of fluoride from aqueous 

solution by calcined Mg-Al-CO 3 layered double 

hydroxides, J. Haz. Mat., B133, 119-128. 

Miyata S., (1975), The synthesis of hydrotalcite-like 

compounds and their structures and physico-chemical 

properties – I: The systems Mg 2+ -Al 3+ -NO 3 - , Mg 2+ - 

Al 3+ -Cl - , Mg 2+ -Al 3+ -ClO 4 - , Ni 2+ -Al 3+ -Cl - and Zn 2+ - 

Al 3+ -Cl - , Clays Clay Miner., 23, 369-375. 

Praus P., Turicova M., (2007), A phisico – chemical study 

of the cationic surfactants adsorption on 

montmorillonite, J. Braz. Chem. Soc., 18, 378-383. 

Toxicological Profile for Chromium, (1998), Agency for 

Toxic Substances and Disease Registry (ATSDR), 

U.S. Public Health Service, U.S. Department of 

Health and Human Services, Atlanta, GA. 

Vaccari A., (1998), Preparation and catalytic properties of 

cationic and anionic clays, Catal. Today, 41, 53-71. 

515

516




______________________________________________________________________________________________ 

VIRTUAL ENVIRONMENTAL MEASUREMENT CENTER BASED ON 

REMOTE INSTRUMENTATION 

Marius Branzila 1∗ , Carmen Alexandru 2 , Codrin Donciu 1 , 

Alexandru Trandabăţ 1 , Cristina Schreiner 1 

1 Technical University of Iasi, Faculty of Electrical Engineering, 51-53 Mangeron Blvd., 700050, Iasi, Romania 

2 Technical University of Iasi, Faculty of Chemical Engineering, 71 Mangeron Blvd., 700050, Iasi, Romania 

Abstract 

In this paper we propose system architecture for virtual environmental measurement center based on remote instrumentation. We 

use Internet facilities for transmission of the information. The station center can be used in remote control mode. Circumstance 

data can be collected with logging field station (Web-E-Nose or meteorological station). The environmental measurement center 

collects and automatically save data about the temperature in the air, relative humidity, pressure, wind speed and wind direction, 

rain gauge, solar radiation and air quality but also can perform smell detection using a purposed Web-E-Nose. Also can analyze 

historical data and evaluate statistical information and publish data in the Internet using LabVIEW Web Server capability. 

Key words: environmental monitoring, remote and virtual instrumentation, LabVIEW Web Server, Web-E-Nose 


The EU-funded conference on "Environment, 

Health, Safety: a challenge for measurements", held 

in Paris in June 2001, recognized the need to improve 

the performance of environmental measurement 

systems and their harmonization at EU level, to foster 

the dialogue between the providers of measurement 

methods and the users of measurement results, and to 

prepare the base - by establishing special 

communication tools – for the integration of research 

expertise and resources of environmental monitoring 

across Europe. The concept presented herein aims to 

respond to this actual challenge by combining the 

latest software trends with the newest hardware 

concepts in environmental monitoring, towards 

providing reliable measurement results and 

representative environmental indicators, evaluating 

trends and quantifying the achieved results in order to 

manage the potential environmental risk in 

compliance with European legislation and local 

particularities. 

On the other hand, the climate change and the 

unpredictable environmental phenomena occurring in 

the last years impose new and modern meteorological 

stations, updated to new evaluation conditions, and 

offering remote access to measurement infrastructure 

(Branzila et al., 2006). 

The system presented below gives such an 

opportunity of performing measurements under real 

conditions from a remote location, of an optimum 

access to sophisticated and/or expensive apparatus 

and instrumentation - even geographically distributed, 

and/or of repeating the same experience for a certain 

number of times, at either convenient or unpredictable 

hours, with minimum support from the technical staff 

(Trandabat et al., 2005). 

For this purpose, a new concept of performing 

high-speed data acquisition based on remote sensors, 

and an accurate transmission and processing of the 

meteorological parameters towards obtaining useful 

data for the users was developed in connection with 

the centre services. New methods of interconnecting 

hardware and dedicated software support were 

successfully implemented in order to increase the 

quality and precision of measurements. 

In the same time, the Web concept itself is 

changing the way the measurements are made 

∗ Author to whom all correspondence should be addressed: branzila@ee.tuiasi.ro

Brinzila et al. /Environmental Engineering and Management Journal 6 (2007), 6, 517-520 

available and the results are distributed/ 

communicated. Many different options are occurring 

as regards reports publishing, data sharing, and 

remotely controlling the applications (Girao, 2003). 

2. The presentation of the system architecture 

An adaptive architecture based on web server 

application is proposed, in order to increase the 

performance of the server that hosts a dedicated 

(environmental monitoring) Web site, and customize 

the respective site in a manner that emphasizes the 

interests of the clients. The most virtual laboratories 

normally provide access either to one remote 

application, or accept only one user at a time. The 

system presented below provides a multitask 

connection, by accessing different detectors, working 

with different clients, and offering different variants 

for dedicated remote jobs, including technical tests of 

terminals, direct measurements of environment 

parameters, remote expertises, technical 

demonstrations or vocational training and education 

(Fig. 1). 

soil etc. and web-E-nose pollution monitor). The 

following procedures are implemented on laboratory 

server: dynamically allocation, web interfaces and 

Slab-SL interface. The communications between 

Centre server and each measurement workstation are 

performed by bi-directional interfaces SL-Slab and 

Slab-SL. On the front panel of application, the setup 

parameters are prescribed, and the data are transferred 

to the e-multitask interface. From the main web page 

of the centre server, the operator has the possibility to 

directly and selectively supervise the measurements 

protocols and select the parameters display, the 

publishing procedure, warning degree etc. On the 

other hand, due to the multitask facility, the number 

of users (clients) connected in the same time - to 

exploit the results - may become unlimited. 

We propose an Internet Based Environmental 

Monitoring Center with an increasing data exchange 

speed of information between the small 

meteorological distributed centers and the other hand 

all the world can see the evolution of meteorological 

parameters using World Wide Web. In this case we 

can warn the people in utile time about bad weather. 

Electronic mail messages are automatically generated 

to notify researchers about any identified anomalies. 

The data are then stored in secure electronic databases 

and made available for retrieval and analysis via 

standard web browsers. Authorized users may select 

any portion of the data and conduct a variety of 

predefined, automated analysis procedures or import 

the data into local spreadsheets, databases, or other 

local analysis software. 

Fig. 1. System architecture for remote and distributed 

environmental measurement center 

The instrumentation control and 

communication software has been designed under 

LabView graphical programming language. In 

particular, the PC-server – via TCP/IP protocol and 

the client-server - via CGI (Common Gateway 

Interface) technology, have the important role of 

developing the PC-instruments communication. CGI 

simply defines an interface protocol by which the 

server communicates with the applications. A 

dedicated software package supports the CGI 

applications in form of virtual instruments, used to 

develop interactive applications for Web-enabled 

experimental set-ups (that may be geographically 

distributed stations or expensive instruments, 

distributed areas of specialized sensors for water, air, 

Fig. 2. The main page of the virtual environmental 

measurement center and Virtual Laboratory for on-line 

measurements 

The authors propose in the same time an 

educational measurement remote system. Today, 

many academic institutions offer a variety of webbased 

experimentation environments so called remote 

laboratories that support remotely operated physical 

experiments. Such remote experiments entail remote 

operation of “distant” physical equipment offering 

students more time for laboratory work. This is one 

518

Virtual environmental measurement center based on remote instrumentation 

way to compensate for the reduction of lab sessions 

with face-to-face supervision without significant 

increase of cost per student. Remote experiments are 

adapted to the flexible environment of the students of 

today and permit low cost methods for lab work 

evaluation. Web-based experimentation is an 

excellent supplement to traditional lab sessions. The 

students can access lab stations outside the laboratory 

and perform experiments around the clock. It is 

possible to design virtual instructors in software 

which will protect the equipment from careless use; 

also theft of equipment will not be a problem. 

Interfaces enabling students to recognize on their own 

computer screen the instruments and other equipment 

in the local laboratory may easily be created. Apart 

from the fact that each student or team of students 

works remotely in a virtual environment with no faceto-face 

contact with an instructor or other students in 

the laboratory, the main difference between a lab 

session in the remote laboratory described here and a 

session in a local laboratory is that it is not possible 

for students to manipulate physical equipment e.g. 

wires and electronic components with their fingers in 

a remote laboratory. 

In this way, the architecture of the system has 

two mains components: 

• client user that uses a client computer and 

• measurement provider who disposes the server 

with the web site of the virtual laboratory. 

Two cases are possible for remote teaching 

and education. In the first case, the professor from 

server room, after he set the students connected in this 

way, the students from their home study points can 

receive and follow the lessons. The number of 

students connected in the same time is unlimited. All 

communication software is designed under LabVIEW 

graphical programming language. The main web page 

is located in server that allows the access to every 

station, using a connection link. In this machine a 

web server is running. The LabVIEW server 

represents the back up for the individual stations. 

In the second case the server is set to all user 

masters. The students are able to perform the 

connection via modem and provider until server, in 

order to training and practice the programs. An 

adaptive Web server application tries to increase the 

performance of the Web server that hosts a Web site, 

as seen from the point of view of clients. The 

adaptiveness is based on the customization of the 

Web site in a manner that emphasizes the interests of 

the clients. Our server with dynamic allocation of 

client number is auto restarting. 

The monitories parameters are the fallowing: 

air temperature (T1-T4), humidity (HR1-HR2), 

pressure (P), wind speed (WS) and wind direction 

(WD), rain gauge (RG), solar radiation (SR), and air 

quality (AQ) using the Web-E-Nose. The sensor types 

and accuracies are listed in Table 1. 

The meteo-system architecture is composed 

as follows: 

• the specialized sensors, 

• signal conditioning circuit, 

• power supply - rechargeable batteries 

• a data acquisition board with data transfer by 

RS232 port, 

• PC meteo-host, and the server provided with 

an Ethernet controller, 

• PC video-host 

The main components of the Web E-Nose with 

data distribution by Internet: 

• sensor array that “sniffs” the vapors from a sample 

and provides a set of measurements. 

• prototype data acquisition board SADI 

• a microcontroller 

• Tibbo Ethernet server, 

The microcontroller is the WebE-Nose 

“brain” having the roll to communicate with the 

SADI and Tibbo Ethernet server, acquiring 

information from the gas sensors and SHT11 

temperature and humidity sensor, processing data for 

pattern recognition and transmit the decision by 

RS232 protocol to the Ethernet server. 

Table 1. Gradients of environmental sustainability 

Parameter Sensor Accuracy 

0.5°C accuracy 

precision integrated-circuit 

Temperature 

guaranteeable (at 

centigrade temperature. 

+25°C) 

Humidity 

Wind speed 

Wind 

direction 

Rain gauge 

Pressure 

Solar 

radiation 

(total sun and 

sky) 

the RH sensor is a laser trimmed 

thermoset polymer capacitive 

sensing element with on-chip 

integrated signal conditioning. 

the sensor consists of a 

lightweight 3-cup anemometer, 

which is mechanically coupled 

to an AC generator. 

the sensor consists of a vane and 

counterweight assembly, which 

is mechanically coupled to a 

potentiometer 

tipping bucket 

0.01 inch resolution 

the sensor is made up of a 

bellows, which is directly 

coupled to the core of a linear 

variable differential transformer 

(LVDT) 

photovoltaic sensor 

3. Applications and perspectives 

±2% RH, 0-100% 

RH noncondensing, 

25 °C, 

Vsupply = 5 Vdc 

± 2.0 mph (0.90 

m/s) over entire 

range m/s). 

operating range: 0- 

100 mph 

± 3.0° 

±1% at 1” per hour 

±0,02” Hg over any 

±2,00” Hg span 

±10% of the 

standard(48 

junction thermopile 

black and white 

pyranometer) 

Pilot research cooperation for a regional high 

speed environmental measurement centre, based on 

remote instrumentation, was established in 2007 with 

the kind support from the Local Council, Town Hall 

and the local Environmental Agency in Iasi. 

The research is still under development, and 

the target lies in mapping all the residential and 

industrial areas of the county, improving the remote 

instruments and developing the fast communication 

with all distributed meteorological stations in the 

related area and centralizing the data at the central 

station level. 

519

Brinzila et al. /Environmental Engineering and Management Journal 6 (2007), 6, 517-520 

The data will be further processed according to 

a statistical model, allowing the evaluation of peak, 

average and trend parameters and permitting a 

pertinent prediction of pollution - related either to 

temporal (season, day/night, peak hours etc.) or 

geographical parameters (altitude, vicinity etc.), or to 

atmospheric conditions (humidity, wind etc.), or even 

to societal demands, or to other relevant contextual 

circumstances. 

The communication system is in work at this 

time, and will process on-line the data towards an 

active database, even corroborated with other 

information obtained previously or independently 

from the (autonomous) meteorological stations or 

balloons, or from the individually displayed ground 

sensors. By this way, the system primarily receives 

real-time information from the monitored sites, 

evaluates/predicts the potential risk for environment 

safety and can generate automatic reports to the 

central control centre, from where a potential 

pertinent intervention can be eventually done. 

But, nevertheless, the proposed concept may 

be very useful not only for the decisional factors, 

local authorities, accreditation bodies etc., but also for 

the educational process and public aware. The 

proposed concept was tested already as an 

educational tool for the students dealing with 

“Environment Quality and Maintenance 

Management” discipline. 

For higher education purposes, the proposed 

system accomplishes some peculiar tasks of a Virtual 

Laboratory for environment monitoring field, 

according to some of the applications described by 

Branzila M. et al. (2005 and 2006) or Schreiner C. et 

al. (2006). 


The paper presents the architecture of a 

versatile, flexible, cost efficient, high-speed 

environmental measurement centre, based on remote 

instrumentation, and having as final purposes the 

monitoring of the air quality (physical and chemical 

parameters) and the advertising of the air pollution. 

In many locations a basic infrastructure to 

evaluate the environment parameters already exists, 

but a unitary concept of an E-environment centre can 

be used to deliver services of comparable or higher 

quality, at a clear lower cost and a higher speed and 

reliability. 

On the other hand, a prototype of Web-E-Nose 

system was tested, and provided to be well suited for 

repetitive and accurate measurements, without being 

affected by saturation. But the successful 

implementation of such Web-E-Nose concepts for air 

pollution evaluation at larger scales will require a 

careful examination of all costs, either direct or 

indirect, and should demonstrate its societal benefit 

over time. 

The remote and distributed measurement 

system developed as environmental centre may be 

also particularized as virtual laboratory for on-line 

environmental monitoring, helping the formation of 

well trained specialists in the domain. 

References 

Branzila M., Alexandru C.I., Donciu C., Cretu M., (2006), 

Design and Analysis of a proposed Web Electronic 

Nose (WebE-Nose), IPI , LII, 971-976. 

Branzila M., Fosalau C., Donciu C., Cretu M., (2005), 

Virtual Library Included in LabVIEW Environment 

for a New DAS with Data Transfer by LPT, Proc. 

IMEKO TC4 , vol.1, Gdynia/Jurata Poland, 535-540. 

Girao P., Postolache O., Pereira M., Ramos H., (2003), 

Distributed measurement systems and intelligent 

processing for water quality assessment, Sensors & 

Transducers Magazine, 38, 82-93. 

Schreiner C., Branzila M., Trandabat A., Ciobanu R., 

(2006), Air quality and pollution mapping system, 

using remote measurements and GPS technology, 

Global NEST Journal, 8, 315-323, 2006. 

Trandabat A., Branzila M., Schreiner C., (2005), 

Distributed measurements system dedicated to 

environmental safely, Proc. 4th Int. Conf. on the 

Manag. of Tech. Changes, vol.2, Chania, Greece, 

121-124. 

520




______________________________________________________________________________________________ 

MICROWAVE-ASSISTED CHEMISTRY. A REVIEW OF 

ENVIRONMENTAL APPLICATIONS 

Mioara Surpăţeanu 1 , Carmen Zaharia 1∗ , Georgiana G. Surpăţeanu 2 

1 “Gh. Asachi”Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering and 

Management, Bd.D.Mangeron 71A, 700050, Iasi, Romania 

2 Laboratory of Medicinal Chemistry, University of Antwerp 

Abstract 

The extraction of some pollutants from different matrices, the treatment of hazardous and infectious wastes, the destruction of 

refractory compounds and the prevention of noxious emissions are the main environmental applications of microwave-assisted 

chemistry. The advantages and disadvantages of this technique are also considered. 

Key words: microwave-assisted chemistry, environmental application 


In the latest time, microwaves have been 

exceeded the stage of domestic utilization or uses in 

telecommunications. Thus, many other applications 

are reported such as: synthesis of new compounds 

(Ferone et al., 2006; Logar et al., 2006), particularly 

drugs (Larhed and Haldberg, 2001), chemical analysis 

based on hydrolysis (Stenberg et al., 2001), digestion 

reactions or extraction procedures (Chang et al., 

2004), hydrometallurgy (Al-Harahsheh and Kingman, 

2004) and environmental protection, especially for 

accelerating the destruction of some pollutants 

(Horicoshi and Tokunaga, 2006). 

These applications are based on the fact that 

the microwave irradiation procedures assure an 

efficient internal heat-transfer and make possible 

superheating even at atmospheric pressure (Larhed 

and Haldberg, 2001). 

Consequently, a considerable reduction of 

reaction time is obtained and thus microwave 

chemistry proves their efficiency. Other benefits of 

microwave homogenous heating are: milder reaction 

conditions, higher chemical yields or a better 

recovery of volatile elements and compounds, lower 

contamination level, minimal volumes of reagents are 

required, lower energy consumption, more 

reproducible procedures and a better working 

environment (Agazzi and Pirola, 2000). 

2. Microwave chemistry basics 

Microwave is a form of electromagnetic 

energy with wavelength between 1 mm and 1 m that 

corresponds to frequencies between 300 MHz and 

300 GHz. The most commonly frequency of 2450 

MHz is used for microwave chemistry (Larhed and 

Haldberg, 2001; Al-Harhsheh and Kingman, 2004). 

This frequency just affects the rotation energy of 

molecules and the interference with 

telecommunications frequencies are avoided. 

The heating effect of microwaves is mainly 

based on two mechanisms: dipolar polarisation and 

conduction. 

Dipolar polarisation is due to the fact that the 

dipole is sensitive to external electric fields and will 

attempt to align with them by rotation but this motion 

is prevented by intermolecular inertia. Depending on 

irradiation frequency, the dipole may react by 

aligning itself in/out phase with the electric field. The 

microwave frequency is low enough that the dipoles 

have time to respond to the alternating field, and 

therefore to rotate, but high enough that the rotation 

does not precisely follow the field. As the dipole 

∗ Author to whom all correspondence should be addressed: czah@ch.tuiasi.ro

Surpateanu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 521-527 

reorientates to align itself with the field, the field is 

already changing and a phase difference exists 

between the orientation of the field and that of dipole. 

This phase differences cause energy to be lost from 

the dipole in random collisions, and to give rise to 

dielectric heating (Whittaker, 1997). 

Conduction mechanisms are related to 

movement of charge carriers (electrons, ions etc.) 

under the influence of the electric field. As a result of 

ion movements and collisions the conversion of 

kinetic energy to thermal energy occurs. 

In conclusion, the mechanism of microwave 

heating in the case of an electric conductor includes 

both dipolar polarisation of polar substances and 

conduction mechanism of ions in liquid phase or 

locked up in solids interstices. 

3. Microwave equipment and sample preparation 

First experiments concerning the application 

of microwave heating effect to chemical reactions 

were performed with multi-mode domestic oven. In 

these ovens microwaves are heterogeneously 

distributed, and less-defined regions of high and low 

energy intensity are produced. Actually, a large 

variety of microwave equipment is found on the 

market, which assures well-defined regions of 

maximum and minimum field strength (Larhed and 

Haldberg, 2001). These equipments must be provided 

with reliable temperature control system to assure an 

efficient application of microwave irradiation as 

energy source. Also, an adequate vessel must be used. 

Open vessel systems may be used but the closed 

vessel has some advantages. This is because 

microwaves only heat the liquid phase, while vapours 

do not absorb microwave energy. The temperature of 

the vapour phase is therefore lower than the 

temperature of liquid phase and vapour condensation 

on cool vessel walls takes place (Agazzi and Pirola, 

2000). As a result, the actual vapour pressure is lower 

than the predicted vapour pressure and this thermal 

non-equilibrium is a key advantage of microwave 

technology, as very high temperatures can be reached 

at relatively low pressures. 

The most limiting factor of microwave closed 

vessel are related to sample amount. This is because 

the larger sample amount, the higher is the pressure 

generated by the reaction. 

Thus, the microwave degradation of phenolcontaining 

polymeric compounds was accomplished 

by placing closed vessel inside a commercial oven 

(Chang et al., 2004). The microwave system was 

equipped with a Teflon-coated cavity and a 

removable 12-position sample carousel, a sensor for 

pressure measurements and an optical fibber to 

monitor and control the digestion temperature. 

Sometimes the heating microwave power is 

associated with UV irradiation to assure the 

degradation of refractory pollutants e.g. 

chlorophenols and so the equipment is completed 

with a low- or medium-pressure mercury lamp as UV 

light source (Cirva et al., 2005; Horicoshi et al., 

2006). 

4. Environmental applications of microwave 

chemistry 

The most important and directly applications 

of microwaves assisted chemistry into environmental 

field are related to extraction of some pollutants 

(especially persistent organic pollutants, POP) from 

liquid or solid media in the view of their analysis 

(Basheer et al., 2005; Fountoulakis et al., 2005), in 

the treatment of hazardous and infectious wastes 

(Gan, 2000; Diaz et al., 2005) and, also, in a range of 

environment-related heterogeneous catalytic reaction 

systems like as: the decomposition of hydrogen 

sulphide, reduction of sulphur dioxide with methane, 

reforming of methane with carbon dioxide etc. 

(Zhang and Hayard, 2006). 

Generally, chemical reactions based on 

microwave heating are characterised by a good 

reproducibility, are cleaner that those by traditional 

way (water or oil bath) and many times lead to high 

efficiency. Supplementary advantage of microwave 

assisted chemistry is their applicability both to 

homogenous reactions in aqueous or non-aqueous 

solutions and dry media reactions. This ultimate 

aspect was considered for the application of heating 

microwave effect to improve the yield of metal 

extracted from minerals simultaneous with the 

increasing demand for more environmental friendly 

processes. 

Many papers deals with the extraction of 

metals such as copper, gold, nickel etc. from their 

ores by microwave-assisted leaching, process more 

attractive comparatively with pyrometallurgy due to 

economical, technical and environmental reasons (Al- 

Harahsheh and Kingman, 2004). Thus, it was reported 

that by heating chalcopirite with concentrated 

sulphuric acid in an adapted domestic microwave 

oven (20 minutes, 200-260°C, 2,45 GHz), the 

leaching reaction product in water; the copper 

extraction was between 90-99% (Hsieh et al., 2007). 

In the same time the elemental sulphur was captured 

and only low volumes of sulphur dioxide was 

produced. The improvement of copper extraction was 

explained by the thermal convention currents 

generated as the result of different rate heating of 

liquid and heterogeneous reaction system. Similarly 

results were obtained for gold leaching from its 

refractory ores, especially pyrite and arsenopyrite. 

The enhancement of gold leachability after 

microwave pre-oxidation was explained by the 

formation of a porous (hematite) structure, which 

favorize gold extraction in a cyanide solution (Huang 

and Rowson, 2000). 

The same microwave heating effect was 

applied for coal desulphuration as pre-treatment to 

minimise SO 2 emissions during burning (Johnes et 

al., 2002). 

522

Microwave assisted chemistry-a review of environmental application 

Other applications of microwave heating effect 

were focussed on environment-related heterogeneous 

catalytic reactions such as the decomposition of 

hydrogen sulphide into hydrogen and sulphur and 

reduction of sulphur dioxide with methane (Zhang 

and Hayard, 2006). Thus, to reduce the hydrogen 

sulphide emissions level into the atmosphere, it has 

been investigated the catalytic decomposition by 

microwave heating. The reactions were performed 

under continuous flow conditions in tubular quartz 

reactors using as catalyst either an impregnated 

molybdenum sulphide on γ-alumina or a 

mechanically mixed sample of molybdenum sulphide 

on γ-alumina. The temperature in the microwave 

cavity was monitored using an optical fibre 

thermometer. It was found that the H 2 S conversion 

degree under microwave conditions was much higher 

than those obtained with conventional heating at the 

same temperature, especially with mechanically 

mixed catalyst. The enhancement of the reaction rate 

and product selectivity under microwave conditions 

must be attributed to thermal effects which may result 

because of differences between the real reaction 

temperature at the reaction sites and the observed 

average temperature. 

Microwave-assisted extraction technique is a 

new procedure used especially to recovery of POPs 

from soils, sediments and sewage sludge (Basheer et 

al., 2005; Horikoshi et al., 2006; Hsieh et al., 2007). 

Many papers underlines the advantages of this 

technique over the other new (sonication, pressurised 

liquid extraction and supercritical fluid extraction) or 

classical methods (Soxhlet extraction) but also their 

limitations. 

Microwave-assisted extraction (MAE) is based 

on the nonionising radiation that causes molecular 

motion by migration of ions and rotation of dipoles, 

without changing the molecular structure 

(Fountoulakis et al., 2005). Due to the principles of 

microwave heating the choice of the solvent depends 

on its ability to absorb microwaves, defined by its 

dielectric constant ε (Budzinski et al., 1999). Nonpolar 

solvents do not absorb microwave energy and 

therefore such solvents have poor extraction 

efficiencies compared to polar solvents or mixture of 

solvents at least one of which must be polar. 

It was showed that the addition of water 

facilitates non-polar organic solvents to absorb 

microwave energy and so improves the release of 

target analytes from sample matrix (Basheer et al., 

2005). This is because at high pressure and 

temperature its dielectric constant, viscosity, and 

surface tension become low these facts facilitating the 

extraction from solid samples of the organic 

compounds having different polarities. Nevertheless, 

because of low selectivity the main drawback of 

MAE is the need of a cleanup procedure (Yafa and 

Farmer, 2006; Pastor et al., 1997). 

Thus, to overcome this disadvantage, a 

microwave-assisted extraction and partition method 

(MAEP) using water-acetonitrile and n-hexane was 

studied to determine some pesticides (trifluralin, 

metolachlor, chlorpyriphos and triadimefon) from 

agricultural soils (Fuentes et al., 2006). 

Studies were carried out using sieved soils (2 

mm mesh) with diverse physico-chemical properties 

collected (0-20 cm depth) in different agricultural 

zones in Chile. Aliquots of spiked soil were weighed 

and transferred to a microwave extraction vessel and 

the extraction solution (water-acetonitrile) was added 

in 1:1 sample-to-solvent ratio. After homogenisation 

by manual shaking, hexane was added for 

partitioning. The extraction vessel was covered with 

pressure-resistant holders and preheated for 2 min at 

250 W and then 10 min at 900 W, and 130°C 

maximum temperature using a microwave oven 

system (which allows the simultaneous heating of six 

vessels). An optic-fibber probe inside the monitoring 

cell was used to control temperature. After 

microwave irradiation, vessel was water-cooled, 

opened and hexane layer was evaporated at dryness; 

the residue was re-dissolved and directly analysed by 

gas chromatography electron capture detection. It was 

found that the method is efficient and fast to 

determine hydrophobic pesticides at ng g -1 level in 

soil with different clay-to organic matter ratios. 

Among all the studied parameters (time and 

power of irradiation, nature of solvent, percentage of 

water) the quantity of water is of primary importance 

to maximise the recoveries of polycyclic aromatic 

hydrocarbons (PAH) from soils and sediments by 

microwave-assisted extraction technique (Budzinski 

et al., 1999). The studied PAHs range from three-ring 

aromatic compounds (phenanthrene, anthracene) to 

six-ring aromatic compounds (benzo[ghi]perylene), 

and the optimal conditions established by working 

with 0.1 to 1.0 g of freeze-dried sediments and soils 

were as follows: 30% water, 30 ml of 

dichloromethane, 30 W, 10 min irradiation time. The 

extracted aromatic compounds were analysed by gas 

chromatography coupled to mass spectrometry (GC- 

MS). In these conditions the recoveries for all the 

tested samples are very good (more than 85%). In 

comparison with Soxhlet extractions (SE) this 

technique are proved important advantages like as 

decreasing of solvents volumes (2x250 ml for SE up 

to 30 ml for MWAE) and reduction of operational 

time (at least 48 hours for SE and 10 minutes for 

MWAE). 

MWAE was tested at laboratory-scale for the 

extraction of petroleum hydrocarbons from 

contaminated soil in Canada (Punt et al., 1999). It was 

found that microwaves could be used to enhance the 

solvent extraction of the contaminants from the soil 

and that the proprieties of soil greatly affected the 

extent to which the contaminants are removed. 

MWAE also was applied to analyse 

organochlorine pesticides and polychlorinated 

biphenyls (Horicoshi et al., 2006). Thus it was 

developed a MWAE procedure coupled with a liquidphase 

microextraction (LPME) using a porous 

polypropylene hollow fibber membrane (HFM) for 

cleanup, enrichment and extraction of these POPs 

from marine sediments. The sediment samples of 1 g, 

523


air dried to constant mass at room temperature and 

sieved (size 2 mm) were subjected to microwave 

heating with 8 ml of ultrapure water at 600 W. After 

that the extract containing POPs was transferred to a 

10 ml volumetric flask. Sediments were further rinsed 

with 2 ml ultrapure water and the rinsate was 

transferred to the same 10 ml volumetric flask. For 

the enrichment and extraction procedure a particular 

syringe with a cone-tipped needle was used and 

toluene was selected as solvent. Toluene (5 µl) was 

drawn into the syringe and the needle was tightly 

fitted to a 1.3-cm length of HFM that was previously 

heat-sealed at the other end. The HFM was 

impregnated with toluene for 10 s to dilate the 

membrane pores then the syringe needle-HFM was 

immersed 5 mm below the surface of the sample 

solution under agitation on the magnetic stirrer. 

Extraction between the toluene within the HFM and 

the sample solution was allowed to proceed, allowing 

the analytes to diffuse though porous membrane and 

dissolve into the toluene. After the mass transfer of 

analytes from the aqueous sample solution to organic 

phase the toluene in the HFM was withdrawn into the 

syringe, which was then removed from sample 

solution. The extracted compounds (organochlorine 

pesticides such as Lindane, Heptachlor, Aldrin, 

Dieldrin etc. and polychlorinated biphenyls such as 2- 

dichlorobiphenyl, 2,3-dichlorobiphenyl, 2,4,5- 

trichlorobiphenyl etc.) were analysed by GC-MS. The 

proposed method for quantifying POPs exhibits some 

advantages compared to SE or conventional heating 

because is relatively simple, requires a low volume of 

solvent and eliminates carry-over effects through the 

use of disposable HFM. 

Other categories of compounds analysed by 

intermediate of MWAE include nonylphenol 

ethoxylates (NPEO) and nonylphenol (NP), the first 

representing a significant fraction of non-ionic 

surfactant market. NPEO and their metabolites 

exhibit toxic effects on the aquatic organisms due to 

their ability to mimic natural hormones (estrogens) 

inducing endocrine disruption. Those compounds are 

discharged to the environment through the wastewater 

treatment plant effluents and they have been detected 

both in soils and aquatic organisms (Johnes and 

Heathwaite, 1992). 

MWAE was used for the determination of 

NPEO and NO in sewage sludge and method 

efficiency was evaluated as to linearity, repeatability, 

accuracy, and sensitivity (Fountoulakis et al., 2005). 

Thus, it was pursue to develop and optimise MWAE 

for the specifically extraction of the two compounds 

followed by their determination using HPL coupled 

with fluorescence detector. Environmental samples 

were collected from the sewage treatment plants in 

Greece, conserved by immediate addition of 1% 

formaldehyde and, when not immediately analysed, 

were stored in the dark at 4°C. Prior to the analysis of 

NP and NPEO, the samples were filtered and dried in 

the oven at 35°C, and the resulting solids were 

grinded. MWAE procedure was performed on the 

dried samples (0.03-0.3 g) in perfluoroalcoxy (PFA) 

copolymer resin Teflon-lined extraction vessel after 

the addition of 20 ml solvent, namely hexane/acetone: 

1/1 (v/v) or dichloromethan/methanol: 3/7 (v/v). The 

extractions were performed at various conditions of 

temperature (100 and 120°C) and power (600 and 

1200 W). The extraction time was 17 min. After 

cooling, the extracts were concentrated to an 

approximate volume of 1 ml using a rotary vacuum 

evaporator; the resulted concentrate was redisolved in 

10 ml acetonitrile and the organic phase was analysed 

by HPLC-FD after filtration. It was observed higher 

extraction recoveries (61.4% for NPEO and 91.4% 

for NP) when 1 ml water was added to dry sample 

prior to extraction. 

MWAE technique was successful aplicated for 

the determination of some quinolone antibacterial 

agents (flumequine and oxolinic acid) from sediments 

and soils (Prat et al., 2006). Such as many 

antibacterial agents, oxolinic acid (OXO) and 

flumequine (FLU) exhibit great chemical stability and 

high sorption coefficients and these characteristics 

contribute to their accumulation in sediments and 

soils. Half-lives of these compounds are appreciated 

at 150 days (Johnes et al., 2002). The extraction of 

the analytes was performed by liquid-liquid partition 

between a sample homogenate in an aqueous buffer 

solution and a non-miscible organic solvent and 

MWAE was used to improve the speed and efficiency 

of the extraction process. The environmental samples 

(marine sediments and soils) were oven-dried 

(110°C), sieved (90 µm) and stored in the dark at – 

20°C. Before the analysis the samples were thawed 

and, for recoveries studies, were spiked by adding 0.5 

ml of an aqueous standard solution containing OXO 

and FLU to 0.5 g dray sediment or soil sample. The 

mixture was equilibrated by shaking for 15 min and 

then left standing overnight at room temperature in 

the dark. Microwave-assisted extraction was 

performed in a PFTE vessel before the addition of 10 

ml of 1 M phosphoric acid buffer at pH 2 to samples 

prepared as above mentioned with 10 ml 

dichloromethane. After microwave irradiation (22 

min, 90°C) the vessel was air-cooled to below 40°C 

then the content was transferred in a 30-ml glass tube 

and centrifuge (5 min, 4000 rpm). A clean-up step to 

remove some of coextracted compounds was 

introduced consisting in back-extraction in 1 M 

sodium hydroxide. The determination was carried out 

by reversed phase liquid chromatography on an octyl 

silica-based column and fluorimetric detection. 

Resulted solution was filtered by a 0.45 µm nylon 

membrane and injects into chromatograph. The 

absolute recoveries rates were determined from 

spiked samples by comparing peak areas of 

calibration standard solutions. The values range from 

79% to 94% for the whole process. 

In the same manner, microwave assisted 

extraction was used to determine methylmercury from 

polluted sediments in comparison with manual and 

supercritical fluid extraction techniques (Lorenzo et 

al., 1999). The experiments were carried out on freeze 

dried sediment samples sieved to a particle size below 

524


300 µm. Spiked samples were prepared with 

methanol containing known concentration of 

methylmercury to appreciate the extent of recoveries. 

The determination is based on the separation by gas 

chromatography followed by electron capture 

detection. It was showed that manual (conventional) 

and microwave-assisted extraction produce almost 

identical extract. Nevertheless, the conventional 

extraction procedure is time- and labour-intensive (2- 

3 hours) and requires the uses of relatively large 

amounts of toxic organic solvents. Supercritical fluid 

extraction in most cases produces similar recoveries 

with manual extraction and has the advantage that is 

relatively fast (50 min) but matrix effects may be 

important. MWAE provide a reliable and 

advantageous extraction procedure because requires 

smaller volumes of organic solvents than the manual 

technique, and total sample-processing time is 

reduced by the shorter extraction time (usually no 

more than 10 min) and simultaneous extraction of 

several samples. Moreover, the microwave-assisted 

extraction appears to be much less dependent on the 

sediment matrix. 

A novel application of microwave heating 

effect in environmental protection regards the 

treatment and disposal of healthcare wastes (Diaz et 

al., 2005). 

Wastes produced in healthcare facilities in 

developing countries have raised serious concerns 

because of the inappropriate treatment and final 

disposal practices accorded to them. Inappropriate 

treatment and final disposal of wastes can result in 

negative impacts to public health and to environment. 

Some of the more common treatment and 

disposal methods used in the management of 

infectious healthcare wastes in developing countries 

are: autoclaves and retorts; microwave disinfection 

systems; chemical disinfections; combustion and 

disposal on land (dump site, controlled landfill, pits, 

and sanitary landfill). 

Microwave systems in the healthcare waste 

sector commonly require the addition of water. 

Microwave disinfection systems typically consist of 

three major types of equipment: (1) material handling 

equipment, (2) the disinfection equipment itself, and 

(3) environmental control equipment. The 

disinfection area or enclosure includes a hermetically 

enclosed chamber, where the materials to be treated 

are placed and into which the microwaves are 

focused. Microwave systems are designed and built in 

a variety of sizes, ranging from a few kg per hour to 

more than 400 kg per hour. The units can be operated 

as a batch process or in a semi-continous mode. 

Large-scale systems can have from 1 to 6 microwave 

generators and, generally, each generator has a power 

output on the order of 1.2 kW. For microwave 

disinfection process the waste to be treated is placed 

in carts and transported to the treatment facility (e.g. a 

mobile microwave unit). The carts are lifted by a 

hydraulic mechanism and the waste is discharged into 

a hopper after the gate is opened. As the waste is 

introduced into the hopper, steam is injected there and 

the air is extracted from the unit. All extracted air is 

passed through a high efficiency particulate air filter. 

The waste in hopper is forced into a shredder. The 

shredded waste is transported via a rotating screw, 

exposed to steam, and then heated between 95-100 °C 

by means of microwaves. The treated waste may be 

passed through a secondary shredder to achieve a 

higher degree of particle size reduction than with only 

one shredder. 

The disinfection in microwave units is not a 

result of material exposure to the microwaves. The 

steam produced from the moisture in the waste by the 

microwave energy brings about the destruction of the 

pathogenic organisms in the waste. 

Other papers indicate that microwaves proved 

effective in destruction of pathogens in sewage sludge 

(Hong et al., 2004). Thus, the mechanisms and roles 

of microwaves on fecal coliform destruction were 

investigated by different methods like as bacterial 

viability tests, electron transport system and β- 

galactosidase activity assay, gel electrophoresis etc. 

Live/dead cell bacterial viability kits were used to 

investigate the cell wall damage of fecal coliforms 

caused by microwaves compared with that by 

external heating. 

Sludge samples from wastewater treatment 

plant were irradiated in a 200 ml beaker in a 

microwave oven, which operate at a frequency of 

2450 MHz. In general, microwave irradiation for 60 s 

led to almost complete destruction of coliforms while 

external heating needed 100°C. This indicates that 

microwave technology is superior to external heating 

in terms of pathogen destruction, methane generation 

and energy requirement. So, the microwave 

irradiation of sludge appears to be a viable and 

economical method of destructing pathogens and 

generating environmentally safe sludge. 

By means of microwave technology it is 

possible the processing of industrial of hazardous 

industrial waste. Such wastes are currently disposed 

on landfill sites and this practice is concerned in 

groundwater’s pollution as result of some toxic 

compounds leaching. 

Differing from conventional treatments 

microwave irradiation may catalyse chemical 

reactions by a selective heating explained by a special 

dipolar oscillating and dielectric losses effect. Thus, 

reversed temperature gradients can be generated in a 

microwave field and the activation energy in 

sterilisation, sintering and chemical reactions can be 

reduced. 

The microwave irradiation was also used to 

denature the β-glucosidase fraction associated with 

viable microorganisms from soils as an estimate of 

extracelular (abiontic) activity (Knight and Dick, 

2004). This is because the β-glucosidase activity can 

detect soil management effects and has potential as a 

soil quality indicator that could be used in 

conjunction with other soil analyses for several 

reasons. First, it catalyzes the final step in the 

biodegradation of cellulose compounds and the 

subsequent release of glucose to microorganisms. 

525


Thus, it plays a vital role in the large-scale C cycle, as 

well as small-scale processes of releasing a labile 

energy source for microorganisms. Secondly, the 

abiontic form contributes to a significant amount of 

the total activity. Abiontic activity was estimated after 

subjecting soil samples to microwave that likely 

denatured most of the enzyme activity from the viable 

microbial population. The result showed that although 

β-glucosidase activity after microwave irradiation 

appears to be limited as a soil quality indicator, it 

maybe useful as research tool to separate abiontic 

enzyme fraction from activity of viable microbial 

biomass. 

Using microwave technology was processed a 

hazardous metal hydroxide sediment sludge as 

advantageous alternative to jam on the leachate of 

toxic heavy metal ions such as Cu 2+ , Zn 2+ , Cr 3+ , Pb 2+ 

(Gan, 2000). The effectiveness of microwave assisted 

binding and immobilisation of the metal ions within 

the sediment solids was studied in conjunction with 

an evaluation of microwave energy efficiency in 

comparison to the more conventional convective 

heating and drying processes. 

The experiments were carried out on a 

sediment sludge resulted from a PCB manufacturer, 

dewatered through a compression and filtration 

process before microwave treatment. A semiindustrial 

combined convective heating and 

microwave oven was used as microwave equipment. 

An electric air fan heater was externally attached to 

the microwave oven so that hot air, at a constant 

temperature of 96°C, can be transported to and 

circulated within the microwave oven. Such a 

combination allows the heating and drying of solids 

to take place in three distinctively different modes of 

(i) sole heat convection; (ii) sole microwave heating 

and (iii) simultaneous microwave and convective 

heating and drying (combined mode). The moisture 

removal from the sediment sludge was determined by 

differentiating the total sample weight before and 

after the drying process. 

It was found that the energy consumption per 

unit mass at the combined mode decrease with 

increasing total solid mass. Also, it was argues that 

microwave metal ion binding proved an efficient 

procedure to minimise or to prevent the leaching of 

heavy metal ions from hazardous sludge. 

An other environmental application of 

microwave have as starting point the observation of 

many epidemiological studies that a correlation exists 

between the exposure to particulate mater and adverse 

human health effects at concentration commonly 

found in urban areas. Thus, microwave technique was 

used as sample preparation procedures for the 

determination of total and water-soluble trace metal 

fractions in airborne particulate mater (Karthikeyan et 

al., 2006). 

Different size fractions of atmospheric 

particulate matter namely total suspended particulate 

matter, particulate mater with diameter ≤ 10.0 µm, 

and particulate matter with diameter ≤ 2.5 µm were 

collected directly onto different filter substrates 

(Teflon, Zeflour, Quartz) and a closed vessel 

microwave digestion system was used. Half of the 

filter samples were subject to microwave digestion 

program (with HNO 3 -HF-H 2 O 2 ) and after that total 

metals were determined by inductively coupled 

plasma-mass spectrometry. The remaining halves of 

the filters were employed for the microwave-assisted 

extraction of water-soluble trace metal fractions. 

The experimental protocol for the microwave 

assisted digestion was established using two different 

standard reference methods and finally the application 

of the proposed microwave-based sample preparation 

methods was demonstrated by analysing trace 

elements in airborne particulate samples from 

different emission sources. The results show that 

these methods are very simple, fast, reliable and 

quality-assured. They can be used for the analysis of 

numerous air particulate samples collected from a 

network of air quality monitoring stations. 


The microwave energy may be used with good 

results in different related fields to assure the 

environment’s protection. The main applications of 

microwave-assisted chemistry are in extraction of 

some pollutants from different matrices or in their 

destruction. The principals’ advantages of this 

technique are due to the shorter reaction time, 

inexpensive materials, easy application and lower 

contamination level. Other advantages are minimal 

volumes of reagents that are required, lower energy 

consumption and more reproducible procedures. 

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______________________________________________________________________________________________ 

ENVIRONMENTAL POLLUTION WITH VOCs AND POSSIBILITIES 

FOR EMISSION TREATMENT 

Liliana Lazăr ∗ , Ion Balasanian, Florin Bandrabur 

“Gh. Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Engineering Inorganic Substances, 

71A D.Mangeron Bd., 700050 - Iasi, Romania 

Abstract 

Volatile organic compounds (VOCs) constitutes an important class of environmental pollutants, which, together with other 

contaminants as NO x , SO x , CO, NH 3 , CO 2 etc. participate in degradation of atmosphere and exhibit a potential risk for human 

health. VOC emissions may be generated in more than 25 percentages through the use of solvents in different industrial or house 

holding activities. For applying a certain plan concerning the pollution reduction, any user of organic solvents containing VOCs 

should accomplish a proper management of these ones, such as the concentrations of the pollutants to frame within the limits 

regulated by the European legislation. The pollutant emission containing VOCs may be subjected to a treatment process, 

established concordant to their characteristics and provenience, as well as to the possibility and the cost of implementation in the 

technological process. 

In this paper, a scheme for trapping and treatment of the gas emissions resulted from the activities related to degreasing in organic 

solvents containing VOCs is presented. 

Key words: VOC, environmental pollution, solvents, emissions, catalytic incineration 


The volatile organic compounds are 

considered to be organic substances, excluding 

methane, which contain carbon and hydrogen, total or 

partial substituted by other atoms, which exhibit a 

vapour pressure higher or equal to 0.01 kPa at 20 0 C 

and which may be found in gas or vapour state in the 

operation conditions carried-out in units (EC 

Directive, 1999). Due to their specific characteristics 

(high volatility, harmful, toxic or carcinogenic effect), 

the VOC pollutants show a potential risk for human 

health, even at low concentrations in gas emissions. 

In consequence, the VOC pollution reduction and 

control became a major problem at the international 

level in the last decades. The basic objectives of the 

environmental policies consist in ensuring the 

protection and conservation of the nature, as well as 

durable use of its components in accordance to 

regulations regarding the integrated pollution 

prevention and control foreseen by the IPPC 

Directive (EC Directive, 1996). 

The VOC environmental impact consists in 

direct effects, as a result of their specific 

characteristics, as well as in indirect effects that owe 

to their participation in reactions occurring in the 

presence of atmosphere constituents and solar light. 

In these reactions, active radicals that disturb the 

normal cycle of nitrogen in atmosphere may form. 

VOC pollutants are able to participate in depletion of 

the ozone layer, in enhancement of the greenhouse 

effect, in appearance of the photochemical smog 

(Dumitriu and Hulea, 1999). 

The effects of VOCs on the human body 

depend on their chemical nature, concentration in air 

and duration of their action. Most frequently, the 

action of these pollutants occurs at low concentration 

resulting in a chronic or a long–term effects that need 

long period to lead to changes in the human health. 

Very high concentrations yield to acute or immediate 

effects, cases when the body reactions appear fast. 

The VOCs may action not only upon the exposed 

∗ Author to whom all correspondence should be addressed: lillazar@ch.tuiasi.ro

Lazar et al. /Environmental Engineering and Management Journal 6 (2007), 6, 529-535 

population, but also on the descendents, leading to 

transmissible hereditary mutations or congenital 

malformations. 

Evolution of the environmental pollution with 

VOC varied with the level of industrialization and 

urbanization of the society, in the last decade being 

registered a continuous decrease due to the more and 

more severe legislative regulations foreseen by the 

Directive 1999/13/EC and Directive 2004/42/EC. The 

limit values established for VOC emissions resulted 

from using solvents in different activities and plants, 

forced the economic agents to find practical solutions 

for reduction at the sources of emissions and to 

implement them in the technological process. 

The European regulations concerning VOCs 

pollution prevention and control (EC Directive, 1999; 

EC Directive, 2004) are transposed in Romanian 

legislation by Governmental Decision HG 699, 

(2003) modified and added up through HG 1902 

(2004). The Romanian economic agents that use 

organic solvents containing VOC have to implement 

the legislative regulations up to 31.12.2007. Romania 

engaged to reach, in 2010, the limit of 523 . 10 3 tones 

VOC emissions, meaning a reduction of 15 % toward 

1990 (616 . 10 3 tones VOC). Implementation of 

Directive 1999/13/CE in Romanian plants is achieved 

by collaboration with Germany, concordant to the 

PHARE Twinning Project RO/2002/IB/EN/02 

(PHARE Program, 2002). 

Two objectives are foreseen in this paper: 

analysis of the main VOC pollution sources in 

Romania and, especially, in the region of Moldova 

and settlement of a scheme for trapping the VOC 

emissions aiming at achieve the catalytic depollution. 

For selection of the VOC emissions treatment 

method, any economic agent has to carry-out a mass 

balance of the solvents that should constitute the basis 

for calculation of the composition and flow of the 

pollutants emission. In this context, this paper 

presents the mass balance calculated for the case of 

using solvents in order to achieve the degreasing of 

the metallic surfaces. The solvents mass balances 

allow the establishment of VOC consumption, of the 

threshold value of the emission, as well as of limit 

value of fugitive and total emissions in order to 

conform to the operation conditions of these types of 

equipments. By solving the mass balance, the 

solvents user verifies if it conforms to the limit values 

for VOC emissions in the residual gases or in the 

fugitive emissions, but also to the limit values of the 

VOC total emissions. The mass balance analysis 

permits the establishment of a plan for reduction or 

selection of a certain treatment method for the gas 

emissions that meets the regulations. 

2. Environmental pollution with VOC 

2.1. VOC polluting sources in Romania 

air or sea conveyance) are situated on an important 

place in majority of the countries of the world. These 

are followed by the technological stationary sources 

(steam power plants, chemical and metallurgic 

industries, varnishes and paints industries, food and 

pharmaceutical industries, different economic agents 

which use organic solvents municipal, medical or 

industrial incinerators, etc.) and then, by the natural 

sources (volcanoes, gas emanations from soils, 

decomposing processes of organic substances in soils, 

woods burning etc.). 

Analysis of the report from 2001 of Ministry 

of Water, Woods and Environmental Protection, 

Romania (MAPPM Romania, 2001), realized on the 

basis of the stock-taking and classification of the 

sources which generate VOC emissions (by 

EEA/EMEP/CORINAIR method), evidenced the fact 

that (Fig. 1), the main pollutants sources are the 

transportations (> 20 %), solvents manufacture and 

use (≅ 25 %), plants for fuel extraction, distribution 

and burning (> 15 %). 

The biggest number of VOC emissions results 

form different activities or plants that use organic 

solvents. The main categories of activities that lye 

under the incidence of the Directive 1999/13/CE are: 

protective covering of the surfaces (metal, wood, 

plastics, textile, fabrics, leather) and car painting; dry 

cleaning; cleaning and degreasing of the surfaces; 

covering with adhesive; covering of the rolls; shoes 

manufacture; covering agents, varnishes, inks and 

adhesives manufacture; pharmaceutical products 

manufacture; printing; rubber conversion; extraction 

and refining of the vegetal oils and animal fats; wood 

impregnation (EC Directive, 1999). 

In Romania, the stock-taking of the VOC 

pollutant emissions is done by the National Institute 

of Research – Development for Environmental 

Protection, in accordance to codification of the 

activities and consumption thresholds established 

through the legislative regulations (HG 699/2003; HG 

1902/2004). Reporting of the statistic data is done by 

the M.M.G.A. from Romania to the European 

Environmental Agency (www.mmediu.ro). 

On the basis of the national inventory realized 

at the level of the year 2005, it was observed that on 

the whole territory of Romania, 832 functioning 

plants existed, which have been developing activities 

using organic solvents containing VOCs (PHARE 

Program, 2004). 

In order to evidence the percents of every type 

of activity that uses solvents, the data of the national 

inventory were analyzed (Implementation Plan, 

2004), the results being presented in Fig. 2. The most 

important fraction is constituted by the activities of 

wood surfaces covering (> 25 %), followed by other 

diverse activities of covering and cleaning of the 

metallic surfaces, plastics, textiles and fabrics (≅ 

35%), and car painting (7 %). 

From the point of view of the total volume of 

pollutant VOC emitted in atmosphere, as well as of 

the affected sites, the mobile sources (road, railway, 

530


burning in energetic 

and transformation 

industries 

2% 

other sources 

30% 

non-industrial 

burning plants 

8% 

burning in processing 

industries 

1% 

production 

processes 

7% 

fossil fuel 

extraction 

and distribution 

5% 

carcinogenic, genetic modifications inducers, harmful 

for reproduction). Solvents are classified as a function 

of risks phases or combination of these ones 

(attributing the R indicative) and as a function of the 

effects on health in conformity with the legislative 

regulations (HG 699, 2003; HG 1902, 2004; SR- 

13253/1996). 

agriculture 

8% 

waste treatment 

and disposal 

1% 

road conveys 

18% 

other mobile sources and 

units 

3% 

use of solvents 

and other products 

17% 

Fig. 1. Classification of the VOC pollution sources in 

Romania 

varnishes, inks, 

adhesives 

manufacture 

7.9% 

others 

10.8% 

surfaces 

cleaning 

8.9% 

car painting; 

7.0% 

12 

38 

11 

4 

49 

9 

14 

9 

6 

2 

16 

24 

5 

10 

24 

25 

4 

10 

17 

32 

30 

11 

5 

32 

13 

2 

34 

12 

9 

3 

1 

~ 16 % 

of the 

total 

plants 

from the 

country 

adhesive 

coverings 

4.9% 

other types of 

coverings 

17.8% 

18 

21 

7 

6 

10 

7 

shoes 

manufacture 

10.3% 

dry chemical 

cleaning 

5.6% 

wood surface 

covering 

26.7% 

Fig. 2. Percents of the most important activities/plants that 

use organic solvents containing VOC in Romania 

The analysis of repartition of the technological 

sources on counties evidences that, in the counties of 

Moldova, may be found around 25 % from the total 

of the plants that use organic solvents containing 

VOC (Fig. 3). 

Fig. 4. Repartition on counties of the activities of surfaces 

cleaning, car painting and different surfaces covering 

(metallic, plastics, wood, textile etc.) 

Since even for low VOC concentrations, the 

gas emissions exhibit a certain degree of risk upon the 

human health, the economic agents that exploit the 

equipments specified in Directive 1999/13/CE have 

the obligation of applying measures of control and 

reduction of environmental pollution with VOC. In 

this context, as a function of the solvent containing 

VOC consumption threshold, the economic agent 

must obey the limit value of VOC emissions in the 

residual gases and the fugitive emissions or the limit 

value of the total VOC emissions (Table 1) and to 

implement a plan for pollution reduction at source. 

Table 1. Emissions limits imposed by the consumption 

threshold of solvents containing VOC 

(HG 699, 2003) 

Fig. 3. Repartition on counties of the activities /plants that 

use organic solvents 

3. Possibilities to reduce pollution with VOC 

In general, the organic solvents belong to the 

group of the aromatic hydrocarbons, oxygenated 

compounds (alcohols, ketones, esters, and glycolic 

ethers), chlorinated derivatives etc. A part of these 

solvents belong to the classes of carcinogenic, 

mutagenic and toxic substances (CMR substances – 

Consumption 

threshold of solvents 

containing VOC, 

t/year 

Emission 

limit 

mg C/Nm 3 

Diffusive emission 

% form the used 

amount of solvent 

5 – 15 100 25 

> 15 

50 

75 

20 

In general, for reduction of the environmental 

pollution with VOC, there may be applied the 

following activities: treatment of gases resulted from 

a process, with or without solvent recirculation, 

reduction of emissions during the technological 

operations; replacement of the polluting processes 

with new ones that do not involve emission of volatile 

organics in atmosphere. 

531


Treatment methods are grouped in two 

categories: non-destructive (condensation, adsorption, 

membrane separation) or destructive (thermal 

incinerators, catalytic incinerators, catalytic photodegradation, 

and bio-degradation. The nondestructive 

techniques allow the recovery of the 

solvents for their use as raw material, while the 

destructive techniques are utilized for oxidative 

treatment of VOC emissions, with recovery of the 

heat resulted in the process (EPA, 1995; Dumitriu and 

Hulea, 1999). Selection of a certain treatment method 

is done considering: the process that generates 

pollutant emissions with VOC, the nature and flow of 

the emission, the minimum, average and maximum 

concentrations of VOC, the costs etc. These criteria 

involve a good management of the solvents within the 

technological phases of the activities that lead to 

VOC emissions (EPA, 1995; Lazaroiu, 2000). 

4. The mass balance of the solvents in a plant for 

surfaces degreasing 

4.1. Solvents management 

Within a technological process for surface 

covering with decorative-protective purposes, a stage 

for chemical degreasing in organic solvents is 

foreseen aiming at partially removal of the animal and 

soluble vegetal fats. Usually, degreasing occurs in a 

cave with a parallelepiped shape, containing a 

covering device and manufactured by materials 

resistant to the action of the solvents. 

Due to degreasing of the metallic surfaces in 

organic solvents, result VOC emissions that should be 

controlled such as the emission limit value, 

concordant to the solvent consumption threshold, not 

to be exceeded. The control of these emissions 

involves a good management of the solvents, 

consisting in establishment of the mass balance for 

the degreasing industrial activity. The solvent 

consumption for a range of 12 months is determined 

through the mass balance, and the proof of fulfilling 

certain requirements regarding the limit value of 

fugitive and total emissions, respective, in accordance 

to the regulation is achieved (Table 1). 

For the accomplishment of the solvents mass 

balance, all the input and output flows containing 

VOC should be considered. In Fig. 5, the input and 

output flows that constitute the basis of the solvents 

mass balance are presented (HG 699, 2003). 

4.2. Calculus of the solvents mass balance 

Taking into account the solvents management 

plan and the methodology for calculus of solvents 

mass balance (HG 699, 2003), the mass balance for 

the cases of four solvents frequently used for 

degreasing of metallic surfaces, such as carbon 

tetrachloride, ethylene trichloride, acetone, butanol, 

toluene, is further presented. Considering the yearly 

necessary amounts of solvent ranged between 5 and 

15 t/year, in Tables 2 and 3, the solvents consumption 

and the mass balance are shown. 

Fig. 5. The input and output flows needed for calculus of the solvents mass balance 

532


The solvents consumption (CS) is the sum of 

the solvents partial consumption, established as a 

result of using the solvents purchased during 12 

months (I 1 ). From this amount, the solvents recovered 

for reusing are subtracted (O 8 ), in the case they were 

not sold as products (O 7 ) or used within the same 

process (I 2 ). The calculus formula may be written as, 

Eq.(1): 

CS = (I 1 + I 2 ) – (I 2 + O 8 ) = I 1 – O 8 (1) 

Total emission (E) is the sum of fugitive 

emission value (F) and residual gases controlled 

emission (O 1 ), Eq. (2): 

E = F + O 1 (2) 

Fugitive/diffusive emissions (F) should be 

determined using the indirect method, subtracting 

from the used solvents flows (excepting I 2 ) the flows 

that are not framed in the category of diffusive flows 

according to Eq. (3): 

F = I 1 – O 1 – O 5 – O 6 – O 7 – O 8 (3) 

The determined fugitive emissions should 

not exceed the limit value regulated by legislation 

(HG 699, 2003, HG 1902, 2004). The limit value of 

the fugitive emission is calculated with formula Eq. 

(4): 

( ) 

X = 100⋅ F I + I , % 

(4) 

F 1 2 

From the analysis of the solvents mass balance 

one can see that the fugitive emissions exceed the 

regulated limit value, meaning 25 % from the total 

solvent consumption (Table 1). The high value of the 

fugitive emissions leads in exceeding of the limit 

proposed for the value of the final emission, which is 

100 mg C/Nm 3 concordant to regulation (EC 

Directive, 1999). The total organic carbon content of 

the emission (mg C/Nm 3 ) increases with the increase 

in the number of carbon atoms from the solvent 

molecular structure. At the same time, one may 

observe that the requirements of the Directive 

1999/13/EC are not satisfied. These requirements 

have foreseen limit concentrations of 20 mg C/Nm 3 

for an emission flow of 100 g/h, in the case of using 

organic solvents containing halogenated VOC and 2 

mg C/Nm 3 , respectively, for an emission flow of 10 

g/h, in the case of using organic solvents containing 

carcinogenic or mutagenic VOC. 

The solvents mass balances accomplished for 

the presented cases show that it is necessary a 

rigorous control of the emissions such as, finally, not 

to result more than 25 % fugitive emissions inside the 

industrial precinct and, in the same time, 

environmental pollution should be prevented by a 

good trapping of the residual emissions. 

Solvent 

Solvent 

Carbon 

tetrachloride 

Ethylene 

trichloride 

Chemic 

al 

formula 

Table 2. Establishment of solvents consumption for degreasing of metallic surfaces 

mol 

C 

Molecular 

weight 

kg/mol 

CCl 4 1 152 1.605 

C 2 HCl 3 2 131.5 1.471 

Acetone C 3 H 6 O 3 58 0.79 

Butanol C 4 H 10 O 4 74.12 0.81 

Toluene C 7 H 8 7 92.14 0.87 

*)Multiplying factor for target emission = 3.5 

Yearly 

VOC 

inputs I 1 , 

kg/year 

O 1 , 

kg/year 

50%I 1 

Amount yearly 

Density, consumed and disposed, 

kg/m 3 kg/year L/year 

Conte 

nt of 

VOC, 

% 

Yearly VOC 

inputs, 

I 1 , kg/year 

Content 

of 

impuritie 

s, kg/year 

Target 

emission * 

) 

kg/an 

750 1203.8 723.8 26.25 91.9 

96.5 

15000 24075.0 

14475.0 525.0 1837.5 

750 1103.3 727.5 22.5 78.8 

97 

15000 22065.0 

14550.0 450.0 1575.0 

750 592.5 716.3 33.8 118.1 

95,5 

15000 11850.0 

14325.0 675.0 2362.5 

750 607.5 712.5 37.5 131.3 

95.0 

15000 12150.0 

14250.0 750.0 2625.0 

750 652.5 723.8 26.3 91.9 

96.5 

15000 13050.0 

14475.0 525.0 1837.5 

Table 3. Mass balance for the solvents used in degreasing of metallic surfaces 

O 2 , 

kg/year 

5%I 1 

O 3 , 

kg/year 

O 4 , 

kg/year 

40%I 1 

O 5 , 

kg/year 

O 6 , 

kg/year 

5%I 1 

O 7 , 

kg/year 

O 8 , 

O 

kg/yea 9 , 

kg/year 

r 

F, 

kg/year 

X F , 

% 

Total 

emission 

E, kg/year 

Carbon 723.8 361.9 36.2 0 289.5 0 36.2 0 0 0 325.7 45 687.6 67 55 

tetrachloride 14475.0 7237.5 723.8 0 5790.0 0 723.8 0 0 0 6513.8 45 13751.3 1333 55 

Ethylene 727.5 363.8 36.4 0 291.0 0 36.4 0 0 0 327.4 45 691.1 155 140 

trichloride 14550.0 7275.0 727.5 0 5820.0 0 727.5 0 0 0 6547.5 45 13822.5 3098 140 

Acetone 

716.3 358.1 35.8 0 286.5 0 35.8 0 0 0 322.3 45 680.4 519 875 

14325.0 7162.5 716.3 0 5730.0 0 716.3 0 0 0 6446.3 45 13608.8 10373 875 

Butanol 

712.5 356.3 35.6 0 285.0 0 35.6 0 0 0 320.6 45 676.9 538 886 

14250.0 7125.0 712.5 0 5700.0 0 712.5 0 0 0 6412.5 45 13537.5 10766 886 

Toluene 

723.8 361.9 36.2 0 289.5 0 36.2 0 0 0 325.7 45 687.6 770 1180 

14475.0 7237.5 723.8 0 5790.0 0 723.8 0 0 0 6513.8 45 13751.3 15396 1180 

Flow C, 

kg C/ 

year 

Conc. 

mg C/m 3 

533


Fig. 6. The block-diagram for the process of catalytic purification of pollutant emission resulted stationary sources 

5. Reduction of pollution with VOC in the case of a 

degreasing plant 

For obeying the limit values of VOC 

emissions in accordance to Directive 1999/13/CE, the 

solvents users may choose a reduction plan. In this 

context, one may appeal to the primary measures for 

pollution reduction in the case of these types of 

emissions: a) taking into account the primary 

measures for replacement of solvents containing high 

amounts of VOC with other containing lower 

amounts; b) insertion of a new technology for 

treatment of the residual emissions inside the 

technological flux. 

In the case of emissions of gases containing 

low VOC content (< 5000 ppm COV), an 

advantageous treatment is the oxidative destruction in 

the presence of a catalyst, process named catalytic 

incineration. This is based on the principle of 

thermal–oxidative destruction of VOC, in the 

presence of a catalyst, ensuring conditions for a total 

oxidation reaction up to formation of CO 2 and H 2 O. 

The catalytic incinerators are constructed in function 

of the user specific requirements, the nature and 

concentration of the organic pollutant, the amount of 

the treated effluent and the method of heat recovery 

(Dumitriu and Hulea, 1999; Heck and Farrauto, 

2002). 

In figure 6, the block-diagram for the process 

of catalytic treatment of gaseous emissions polluted 

with VOC resulted from the stationary technological 

sources, is depicted. 

In general, the incineration technological 

process involves unit operations such as: trapping and 

transport of the pollutant gases, separation of the 

components that may occur to catalyst deactivation, 

heating of the gases based on the external energy or 

on recovered heat, mixing with oxidizing agents, 

catalytic treatment and heat recovery (Balasanian and 

Lazar, 2002). 


In this paper, an analysis of the polluting 

sources with VOC was accomplished, being also done 

a solvents mass balance for the process of decreasing 

of the metallic surfaces, that constitute the basis of the 

solvents management plan, as well as the resulting 

emissions reduction plan. 

The volatile organic compounds are an 

important category of environmental pollutants being 

emitted into the atmosphere in a significantly amount 

as a result of the industrial activities were organic 

substances are used as solvents or diluents. The 

diversity, from the point of view of the chemical 

nature and the physical characteristics specific to the 

solvents (high volatility, flammability, toxicity, 

specific odor, carcinogenic effect etc.), confers to 

VOC emissions a major risk for the human health, 

even when they are present in low concentrations. For 

these reason, the prevention, control reduction at the 

source of pollution with VOC is required, obeying the 

admissible maximum concentration regulated by 

Directive 1999/13/CE. 

Any user of solvents containing VOC should 

give a great importance to the management solvents, 

that is based on the mass balance, which is further 

used for establishment of solvents consumption for a 

period of one year, proving the compliance with the 

limit values for the diffusive emissions, in conformity 

with the yearly consumption threshold, regulated by 

law (HG 699, 2003). 

The solvents mass balance is utilized as a 

system for control and management and for the 

reduction of the costs of plant operation. The 

economic agents gain, in the first time, a total view on 

using domains that need a replacement of the utilized 

solvents being thus, able to recognize easier the weak 

points of the industrial activity. 

534


For complying with the limit values 

concordant to the Directive 1999/13/CE, the 

economic agents may achieve a plan for reduction of 

the environmental pollution with VOC, choosing the 

replacement of the solvents containing high amounts 

of VOC, with others having a lower content or 

inserting in the technological flux of a technology for 

residual gases treatment. 

References 

Balasanian I., Lazar L., (2002), Waste Management, 

(Chapter 6.2. Removal and Treatment of Gas and 

Vapour Polluants), Oros V., Draghici C. (Eds), 

EnvEdu Series, Transilvania University Press, 

Romania, Brasov, 150-171. 

Dumitriu E., Hulea V., (1999), Heterogeneous Catalytic 

Methods Applied in the Environment Protection, BIT 

Press, Iasi, Romania (In Romanian). 

EPA, (1995), Survey of Control Technologies for Low 

Concentration Organic Vapor Gas Streams, U.S. 

Environmental Protection Agency's (EPA's) and 

Office of Research and development (ORD), Control 

Technology Center, EPA-456/R-95-003, May 1995, 

on line at: http://www.epa.gov/ttn/catc 

EC Directive, (1996), Directive of concerning integrated 

pollution prevention and control, Directive 96/61/EC. 

EC Directive, (1999), Directive on the limitation of 

emissions of VOCs due to the use of organic solvents 

in certain activities and installations, Directive 

1999/13/EC. 

EC Directive, (2004), Directive on the limitation of 

emissions of volatile organic compounds due to the 

use of organic solvents in certain paints and 

varnishes and vehicle refinishing products and 

amending Directive 1999/13/CE, Directive 

2004/42/EC. 

Heck R.M., Farrauto R.J., (2002), Catalytic air pollution 

control: Commercial Technology, 2 en ed., Wiley- 

Interscience, New York - USA. 

HG 699, (2003), Governmental Decision 699/2003 

concerning the establishment of measures for 

reduction of emission of volatile organic compounds 

resulted from use of organic solvents in certain 

activities and plants, published in Romanian, Official 

Journal M.Of. No. 489/8.07.2003. 

HG 1902, (2004), Governmental Decision 1902/2004 for 

modifying and adding up of HG no. 699/2003, 

published in Romanian Official Journal , M. Of. No. 

1102/25.11.2004. 

Lazar L., (2006), Air treatment for volatile organic 

compounds removal, Ph.D. Thesis, Gh. Asachi 

Technical University of Iasi, Romania. 

Lazaroiu Gh., (2000), Modern Technologies for Depollution 

of Air, AGIR Press, Bucharest, Romania (in 

Romania). 

MAPPM Romania (2001), Inventory of the emissions of the 

atmospheric pollutants at national level for the year 

2001, On line at: 

http://www.mappm.ro/legislatie/inventar%202001.ht 

ml 

PHARE Program, (2002), Implementation of the VOC’s, 

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labeling of the hazardous substances and compounds. 

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level including heavy metals and persistent organics 

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2004). On line at: www.mmediu.ro 

535

536




______________________________________________________________________________________________ 

SUSTAINABLE IRRIGATION BASED ON INTELLIGENT 

OPTIMIZATION OF NUTRIENTS APPLICATIONS 

Codrin Donciu ∗ , Marinel Temneanu, Marius Brînzilă 

“Gh. Asachi” Technical University of Iasi, Faculty of Electrical Engineering, 53 Mangeron Blvd., 700050, Iasi, Romania 

Abstract 

The present paper proposes the design of a modules system of measurement and control of data distributed transmission, 

implemental on automatic irrigation systems of central pivot or linear movement type. By this it is intended to obtain a complex 

irrigation system that allows optimization of nutrient application. 

Key words: Power line communication, soil conductivity, precision irrigation 


Nutrients such as phosphorus, nitrogen, and 

potassium in the form of fertilizers, manure, sludge, 

irrigation water, legumes, and crop residues are 

applied to enhance production (Shifeng et al., 2004). 

When nutrients are applied in excess of plant needs, 

they can wash into aquatic ecosystems where they can 

cause excessive plant growth, which reduces 

swimming and boating opportunities, creates a foul 

taste and odor in drinking water, and kills fish. In 

drinking water, high concentrations of nitrate can 

cause methemoglobinemia, a potentially fatal disease 

in infants also known as blue baby syndrome. They 

are a lot of directive adopted by the Council of the 

EU concerning the nutrients policy. In December 

1991, was adopted Nitrates Directive. The objectives 

of the directive are to ensure that the nitrate 

concentration in freshwater and groundwater supplies 

does not exceed the limit of 50 mg NO3- per liter, as 

imposed by the EU Drinking Water Directive, and to 

control the incidence of eutrophication. Having set 

the overall targets, the directive requires individual 

Member States, within prescribed limits, to draw up 

their own plans for meeting them. Cadmium and its 

compounds are toxic to human beings and therefore 

appear on the EU’s action list. With the exception of 

phosphate slag, which is a by-product of steel 

production and in decreasing supply, almost all 

phosphate fertilizers contain traces of cadmium. 

After collaboration between EFMA (European 

Fertilizer Manufacturers Association) and IFA 

(International Fertilizer Industry Association) the 

Code of Best Agricultural Practices was developed. 

The recommendations provided by the codes 

encourage appropriate application rate, correct timing 

of the application and the use of a suitable type of 

fertilizer and a correctly calibrated fertilizer spreader 

(Sun et al., 2000). 

During the last few years, in the economically 

advanced countries a new notion appeared referring 

to the agricultural practicability called “precision 

agriculture” one of its constituents being “the 

precision irrigation”. This new approach supposes the 

entrapment of new multidisciplinary technologies on 

the classical structures, such as the satellite 

geographical localization, distributed measurements 

and transmissions, micro informatics, broadening the 

view that in the maintenance and exploitation works 

of the agricultural crops the heterogeneity of the 

working plot of land could be taken into account. In 

the traditional agricultural system the cultivated plot 

of land was evenly treated even though it is known 

for a fact that a plot of land is extremely variable 

from the viewpoint of: soil fertility, topography, 

parasites and weeds attack. Precision agriculture has 

∗ Author to whom all correspondence should be addressed: cdonciu@ee.tuiuasi.ro

Donciu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 537-540 

as purpose a modular administration of incomes 

(seeds, irrigation water, fertilizers, fungicides, 

herbicides, insecticides) by adapting the works of the 

soil, sowing, and fertilizers to the heterogeneity 

characteristics of the plot. 

The precision agriculture notion is based on 

the information provided by the production maps: a 

combine equipped with a production recorder for 

instance, connected to a satellite positioning (GPS), 

allows getting a production map on a certain plot. 

This information associated with other agronomical 

data ensures the income modulation with respect to 

the plot heterogeneity. In order to become e 

operational, these techniques must be joined with a 

series of agronomical models, only after this stage the 

decision can be finalized. The disadvantage of this 

method is that the investigations can be realized only 

in the absence of the crops and not during their 

vegetation period. Nevertheless, in opinion of the 

precision agriculture supporters, this can replace the 

side effect of the treatments evenly applied to the plot 

in the case of the conventional agriculture, through 

adapting the various actions to the plot characteristics 

variability. This way the negative impact of intensive 

treatments upon the environment is avoided. 

2. System architecture 

The present paper proposes the realization of 

measurement and control modules of distributed data 

transmission, implemental on automatic irrigation 

systems so that it may lead to obtaining of an 

intelligent system of irrigation combined with 

automatic nutrients injection, relying on the sensory 

investigation of the environment and soil parameters 

conditions. The decisional algorithm of the control 

centre prescribes combined irrigation recipes 

according to the exploited crop and to its 

development specificity, and the investigation is 

carried out at irrigation cell level, modularly. Data 

flux communication has as a physical support the 

existent infrastructure of power supply of the 

automatic irrigation systems and is developed through 

the Power Line Communications technique (Benzekri 

et al., 2006). The system architecture is so conceived 

that it should allow its implementation on the 

automatic irrigation systems of both circular 

movement (central pivot), and linear movement. 

In order to reach the notion of precision 

agriculture (Yang et al., 2006), which represents a 

model in progress of implementing in all the very 

developed countries and has in view a modular 

administration of incomes in terms of the plot 

heterogenic characteristics, the project proposes the 

introduction of a sensory modules network to entail a 

division of the farming field into characterization 

(Zhao et al., 2007). 

The intelligent irrigation system architecture 

is structured on five main levels, as follows: 

• the irrigation modules level, which join the 

automatic irrigation systems on angular or linear 

movement and which have as main function the 

controlled command of the electro valves for the 

admission of the water-nutrients mixture, in 

accordance with the recipes prescribed by the 

control; 

• the sensors modules level, which are fixed and 

placed at the ground, having as main purpose the 

sampling through sensors of the surrounding cell 

characterization data and their transmission 

towards the control centre; 

• the nutrients injection batteries level, with the role 

of injecting nutrients into the irrigation water, in 

terms of the concentration prescribed by the 

control centre (Ruiliang et al., 1999); 

• the data flux transmission through PLC level, has 

as physical support the network of the power 

supply of the engines operating on the automatic 

irrigation systems and water pumps and realizes 

the data transfer between the control centre on the 

one hand and the irrigation module and the 

nutrients injection batteries on the other (Kubota 

et al., 2006); 

• the decisional level, based on the data resulted 

from the sensors modules level and those 

extracted from its own data basis, of combine 

irrigation recipe, delivers the execution commands 

to the injection batteries regarding the irrigation 

output and the characterization cell geographical 

localization (Mohan et al., 2003). 

The general architecture of the intelligent 

irrigation system is shown in Fig. 1. There can be 

noticed the existence of two independent circuits, one 

of water supply and one of power supply. The water 

supply circuit CAA makes the junction between the 

water supply source AA and the nutrients injection 

batteries BIN. This circuit converts into combine 

supply circuit CLC, after the nutrients injection with 

the pulverization nozzles of the irrigation module MI. 

The electric circuit powers up the engines and the 

pumps afferent to the automatic irrigation system and 

is the data transmission physical environment. 

Fig. 1. The intelligent irrigation system architecture 

538

Sustainable irrigation based on intelligent optimization of nutrients applications 

The irrigation module is set up at the level of 

the mobile arms of the automatic irrigation system 

and it is made up of the communication interface 

IPCL, the microchip control device µP, the radio 

receiver RR and the electro valve EV. On the MI 

module movement, the identification of the 

membership to a characterization cell is performed on 

the grounds of the entering its range of action. The 

emission power of the sensors modules MS is limited 

within the cell and towards its detection there 

interferes the criterion of the emission maximum. 

Following the communication settlement 

between the sensors module transmitter and the 

irrigation module receiver, the data are transmitted by 

the command device µP to the PLC interface, joined 

with the supply circuit of the operative electrical 

engine (Sohag et al., 2005). By the PLC transmission 

the useful information is received by the control 

centre CC, on a computer server. As a consequence of 

the interpretation of the response type data provided 

by the characterization cells sensors are taken the 

control decisions of reaching the limits of the 

nutrients concentrations and relative humidity 

imposed by the data basis. The quality and quantity 

commands are transmitted by the PLC system to the 

nutrients injection batteries, providing the combine 

irrigation agent to the pulverization nozzles, to the 

volume controlling electro valves belonging to the 

irrigation module. 

By the communication system PLC useful data 

are delivered as modulated signal. The signal is of the 

broadband type and the physical environment enables 

multiple operations roll on the same existent 

infrastructure. 

The hardware architecture of the sensors 

module is shown in Fig. 2 and is com posed by a set 

of sensors specialized on the climatic parameters 

detection (temperature, humidity, dew point, speed, 

direction and movement sense of air masses, 

precipitations) and a set specialized on the soil 

parameters detection (conductivity, humidity). For the 

air relative temperature and humidity measurement it 

is used an incorporated sensor on digital output STU, 

made in CMOS technology, which makes it thermally 

safe and stable. This generates a useful signal of 

superior quality, has a very quick response time and 

insensibility at external noises (EMC). The data 

delivered by this sensor are used to forecast the 

degree of the water evaporation off the ground. The 

need to utilize the rain gauge sensor type (SP) comes 

from that the irrigation procedure interruption, during 

precipitations, following the data provided by the soil 

humidity sensor, happens late because of the needed 

time of water permeating through the ground, up to 

the depth where the humidity sensor is set up. The 

data coming from the anemometer SV are used to 

eliminate irrigation unevenness caused by wind 

blasts. 

At the ground level are set the conductivity 

sensor SC, the humidity sensor SU, on whose account 

will be supplied the input data for the estimation 

procedure of the relative nutrients and humidity 

concentration. The bidirectional communication with 

the sensors block is performed through the microchip 

µP and is of the serial type. As the sensors module is 

an independent system it is equipped with a control 

keyboard and a LCD screening. The radio data 

delivery to the irrigation module is done by the 

transmitter ER, having the transmission force so 

adjusted that it should not surpass the characterization 

cell by more than half the radius. The assembly 

supply is performed by a dry B battery. 

Fig. 2. Hardware architecture of the sensors module MS 

The control centre is the physical support of 

the decisional algorithms which operate, relying on 

the data resulted from the level of the sensors 

modules the actions of the executor elements, the 

actors. The data basis found at this level contains 

information referring to the leguminous species 

classification in terms of the water consuming and the 

absorption capacity and it designs irrigation graphs 

regarding the cultivated species, zone climatic factors, 

culture denseness and rows orientation, plant habitus, 

root system and vegetation stage. Besides, beginning 

with this level is programmed the time diagram start 

(the culture initiation) and the spells designated for 

the maintenance works. 

The Intervention and Monitoring Centre CIM 

designates the interface with the human operator in 

the process of supervision and monitoring the control 

actions elaborated by CC and allows the effectuation 

of modifications in the decisional algorithms 

development. Also, starting with this level can be 

completed or modified (upgrade software) the data 

basis with respect to the irrigation networks. Because 

the control centre is configured by the server, one can 

access it from any geographical area where there is 

internet access point. The TCP-IP communication 

between CC and CIM is provided by two dedicated 

virtual instruments, server and costumer. For security 

reasons the login to the server is permitted only on 

password basis. The problems identification and 

improvement with respect to the automatic systems 

irrigation are presented in Table 1. 

539


Table 1. Inconvenient identification 

Automatic irrigation 

disadvantages 

The unfavourable effect of the drops (in 

the case of average and high pressure 

aspersers) upon plants, especially when 

plants are young and blooming) 

The presence of the wind during the 

irrigation, if its intensity outruns 2.5 m/s 

they stay unwatered until 10-25% of the 

crop areas. 

High water losses caused by the global 

irrigation and absence of cell level 

individualized information 

Raised nutrients pollution of the phreatic 

layer 

High level power consuming 

Detection manners used 

by the intelligent irrigation system 

The launching in execution of the 

beginning of the time diagram (crop 

initiation mark) leads to the irrigation 

achievement in terms of the 

multiparametric graphs of the vegetation 

stage. 

The information came from the SV 

anemometer processed by the decisional 

algorithm 

The information from the humidity sensor 

(SU) and processed by the decisional 

algorithm 

The information from the humidity sensor 

(SC) and processed by the decisional 

algorithm 

The information from all the sensors of the 

module (BS) processed by the decisional 

algorithm 

Improving actions used 

by the intelligent irrigation system 

The irrigation time modification inverse 

proportionally with the irrigation pressure and 

maintaining evenly the water volume 

demanded by the respective cell. 

The temporary reduction of the water volume 

used. 

Differentiated irrigation with respect to the 

investigated cell demands. 

Differentiated nutrients insertion in accordance 

with the investigated cell demands. 

The optimisation of the combined irrigation 

process (water and nutrients) by the control 

centre (CC) 


The present paper proposes the design of 

irrigation intelligent system implemental on 

automatic systems of central pivot or linear 

movement type, in order to apply nutrients in optimal 

concentrations. The nowadays irrigation systems 

either are not operational, or offer the farmers the 

needed water at altered times, or have them use 

energy-intensive watering techniques that bring about 

large uneconomic consuming. The proposed system 

offers the following benefits: it offers water to the 

plants at the optimum moment, irrigations are done 

only when and where it is needed (the water 

consuming can be reduced up to 30%), it allows the 

phase fertilizations design, the water losses by 

infiltration are minimum, it presents a high efficiency 

for the watering, it creates conditions favorable to the 

maintenance works mechanization, it can be used at 

most of leguminous cultures and not only, it 

facilitates the applications of the modern technologies 

leguminous plants culture, it permits the exploitation 

of cultivated plots larger than 3 % for vegetable 

gardening, it does not need soil maintenance leveling, 

it permits the watering of certain cultures placed on 

high permeability fields, the possibility to dose 

exactly the irrigation water, which is very important 

especially on the low depth groundwater plots, 

favorable effect upon the microclimate (air 

temperature especially) which is very important in the 

case of certain cultures (cabbage, cucumbers, etc.), 

excessive irrigation is avoided (puddles), it is avoided 

the watering away of the nourishing substances and 

the irrigation is adjusted to the running vegetation 

stage. 

References 

Benzekri A., Refoufi L., (2006), Design and 

Implementation of a Microprocessor-Based 

Interrupt-Driven Control for an Irrigation System, 

E-Learning in Industrial Electronics, 1st IEEE Int. 

Conference on, 1, 18-20 Dec., 68. 

Kubota H., Suzuki K., Kawakimi I., Sakugawa M., Kondo 

H., (2006), High frequency band dispersed-tone 

power line communication modem for networked 

appliances, Consumer Electronics, IEEE 

Transactions on, 52, 44-50. 

Meng H., Guan Y.L., Chen S., (2005), Modeling and 

analysis of noise effects on broadband power-line 

communications, Power Delivery, IEEE 

Transactions on, 20, 630-637. 

Mohan S., Elango K., Sivakumar S., (2003), Evaluation of 

risk in canal irrigation systems due to nonmaintenance 

using fuzzy fault tree approach, 

Industrial Informatics Proc. IEEE Int. Conference 

on, 1, 21-24 Aug, 351. 

Ruiliang P., Peng G., Heald R.C., (1999), In situ 

hyperspectral data analysis for nutrient estimation 

of giant sequoia, Geoscience and Remote Sensing 

Symposium IGARSS '99 Proc., vol. 1, 28 June-2 

July, 395. 

Shifeng Y., Pei L., Okushima L., Sase S., (2004), Precision 

irrigation system based on detection of crop water 

stress with acoustic emission technique, 

Information Acquisition Proc. Int. Conference on, 

1, 21-25 June, 444. 

Sohag M.A., Mahessar A.A., (2005), Irrigation Network 

Regulation through CAD System, Information 

and Communication Technologies First Int. 

Conference on, 1, 27-28 Aug., 170. 

Sun D., Zhang L., Xue M., (2000), The online 

measurements and estimation of nutrient solution 

in greenhouse agriculture, Intelligent Control and 

Automation, Proc. of the 3rd World Congress on, 

3, Hefei, 28 June-2 July, 2155. 

Yang L., Zhen-Hui R., Dong-Ming L., Xin-Ke T., Zhong- 

Nan L., (2006), The Research of Precision 

Irrigation Decision Support System Based on 

Genetic Algorithm, Machine Learning and 

Cybernetics, Int. Conference, 1, 15-18 Aug., 3123 

Zhao Y., Bai C., Zhao B., (2007), An Automatic Control 

System of Precision Irrigation for City Greenbelt, 

Industrial Electronics and Applications, 2nd IEEE 

Conference on, 1, 23-25 May, 2013. 

540




______________________________________________________________________________________________ 

OBTAINING AND CHARACTERIZATION OF ROMANIAN ZEOLITE 

SUPPORTING SILVER IONS 

Corina Orha 1 , Florica Manea 1 , Cornelia Ratiu 2 , Georgeta Burtica 1∗ , Aurel Iovi 1 

1 

”Politehnica” University of Timisoara, P-ta Victoriei no. 2, 300006, Timisoara, Romania 

2 Institutul National de Cercetare-Dezvoltare pentru Electrochimie si Materie Condensata, Str.Plautius Andronescu, Nr.1, Cod 

300224, Timisoara, Romania 

Abstract 

The aim of this work was to obtain Ag - doped zeolite as antibacterial material using natural and sodium form of zeolite from 

Mirsid Romania with the dimensions ranged between 0.8-1.2 mm. The comparative structural characterization of natural and Ag - 

doped zeolite were performed using Laser Induced Breakdown Spectroscopy (LIBS), X-ray Diffraction (XRD), Scanning 

Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Infrared Spectroscopy (IR). In addition, the ion exchange 

total capacities for silver of natural and sodium forms of zeolite were determined. The quantitative assessment of silver amount 

incorporated into zeolite lattice was achieved by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). 

Key words: Ag - doped zeolite, qualitative assessment, quantitative assessment, structural characterization 


In general, the sorption and ion exchange 

properties of zeolites, as well as, their inexpensive 

from the economical aspect can be advantageously 

used in drinking water technology (Cooney et al., 

1999; Woinarski et al., 2006). 

There are several studies concerning the use of 

synthetic and natural zeolites, e.g., A, X, Y, Z and 

clinoptilolite supporting metal ions (Ag, Cu, Zn, Hg, 

Ti) as antibacterial material in water disinfection 

(Inoue et al., 2002; Top et al., 2004; Rivera-Garza et 

al., 2000). 

The mineral properties of natural zeolite from 

Mirsid, Romania, with 68 %, wt. clinoptilolite make it 

suitable for the obtaining of Ag-doped zeolite, with 

antibactericidal activity. It has been found that for the 

uniform retaining of the Ag ion with antibactericidal 

property, the zeolite must exhibit a SiO 2 /Al 2 O 3 molar 

ratio at most 14, this molar ratio being ranged 

between 8.5 to 10.5 for clinoptilolite (Hagiwara et al., 

1990). The antibactericidal activity of Ag-doped 

zeolite depends on the amount of Ag ions 

incorporated into zeolite lattice. If the Ag ions 

amount is the same with the ion-exchange total 

capacity the bactericidal effect of the modified zeolite 

is very poor, due to the other form of Ag as silver 

oxide can be deposited on the zeolite surface. Under 

these conditions, it is required to prevent the 

deposition of such excessive silver onto the solid 

phase of zeolite. 

The aim of our present study was the 

preparation and characterization of Ag – doped 

zeolite, with the dimensions ranged between 0.8-1.2 

mm, which will be used further for drinking water 

disinfection. The ion-exchange total capacities of 

natural and Na form of zeolite from Mirsid, Romania 

were determined. The structural characterizations of 

Ag-doped zeolite with the Ag amount lesser than ionexchange 

total capacity of zeolite for Ag ions were 

investigated relating its further utilization as 

antibacterial material. 


For this study, it was used the natural zeolite 

from Mirsid (Romania), which contains 68%, wt. 

natural clinoptilolite. 

∗ Author to whom all correspondence should be addressed: georgeta.burtica@chim.upt.ro

Orha et al. /Environmental Engineering and Management Journal 6 (2007), 6, 541-544 

The preparation of Ag-doped zeolite requires 

two stages, i.e., in the first stage the natural zeolite 

was chemically treated with 2M HCl and 2M NaNO 3 

to obtain the sodium form. The second stage consists 

of the obtaining of the Ag - doped zeolite by the 

mixing of the sodium form of the zeolite with 0.1 N 

AgNO 3 solution for 3 hours (Hagiwara et al., 1990). 

As a previous stage for the preparation of Agdoped 

zeolites the ion exchange total capacity of the 

zeolite for silver was determined. 1.000 g of zeolite 

with the dimension of pores between 0.8-1.2 mm was 

shaken with 25 mL of 0.1 N AgNO 3 during 3, 5, 7, 12 

and 14 days (Cerjan-Stefanovic et al., 2004). Once 

equilibrium was established water solution was 

separated by filtration from the zeolite phase and the 

Ag amount into zeolite was determined by using 

Inductively Coupled Plasma Atomic Emission 

Spectroscopy (ICP-AES) after sample mineralization. 

The ICP-AES analysis was made with an ICP-AES 

SpectroFlame spectrometer. 

The thermal treatment of Ag – modified 

zeolite was realized in reducer environment at 500°C, 

when Ag - doped zeolite (Z-Ag) was formed and the 

thermal treatment of natural zeolite was not 

performed. To determine the presence of silver within 

zeolite lattice, the samples was analyzed by Laser 

Induced Breakdown Spectroscopy (LIBS). The 

material ablation and the excitation were performed 

with Q-switched Nd:YAG laser with an energy of 12- 

15 mJ, using an Ag standard. 

The morphology and the composition of the 

unmodified/modified zeolite were characterized by 

using X-ray Diffraction (XRD), Scanning Electron 

Microscopy (SEM), Atomic Force Microscopy 

(AFM) and Infrared Spectroscopy (IR). XRD spectra 

were recorded at room temperature on a BRUKER 

D8 ADVANCE X-ray diffractometer using Cu Kα 

radiation (λ = 1.54184 Å, Ni filter) in a θ: 2θ 

configuration. The peaks of the XRD patterns were 

identified using the PCPDFWIN Database of JCPDS, 

version 2.02 (1999). The SEM images were made in a 

Jeol JSM-6300LV scanning electron microscope. The 

AFM images were made in a NanoSurf EasyScan 2.0 

atomic force microscope. The IR spectra were 

recorded in KBr pellet for solid compounds on a 

Jasco FT/IR-430 instrument. 

3. Result and disscusion 

The results of the ion exchange total capacity 

of zeolite for silver that was determined by 

equilibrium of zeolite samples with 0.1 N AgNO 3 are 

shown in Table 1 . 

The form type of zeolite, e.g., natural and 

sodium form did not influence the ion exchange total 

capacity for silver ion. The Ag amount retained into 

zeolite as Ag-doped zeolite was 0.0065 mg/g zeolite 

almost twenty times smaller than the total exchange 

capacity of zeolite for silver, versus 0.008 mg/g 

zeolite (with the dimension of pores between 315-500 

µm). 

Table 1. The ion exchange total capacity of the zeolite 

samples with 0.1 N AgNO 3 solution 

Zeolite type 

Contact time mg Ag/g zeolite 

[days] 

Z-N 3 0.115 

Z-N 5 0.108 

Z-N 7 0.102 

Z-N 12 0.101 

Z-N 14 0.101 

Z-Na 3 0.115 

Z-Na 5 0.107 

Z-Na 7 0.102 

Z-Na 12 0.101 

Z-Na 14 0.099 

Fig. 1 shows the laser spectrum of Ag-doped 

zeolite versus silver standard one to identify 

qualitatively the presence of silver into zeolite. 

Relative Intensity 

328.16; 330.5 * - Ag 

6500 

6000 

Ag standard 

6000 Z-Ag 

5500 

5500 

5000 

5000 

4500 

4500 

4000 

4000 

* 

3500 

3500 

3000 

3000 

2500 

2500 

2000 

2000 

1500 

1500 

1000 

1000 

500 

* 

500 

0 

0 

320 322 324 326 328 330 332 334 336 

Wavelength(nm) 

Fig.1. The laser spectrum of Ag-doped zeolite (Z-Ag) 

The comparative XRD spectra of natural and 

Ag-doped zeolite (Z-Ag) are shown in Fig. 2. 

Intensity 

1400 

1200 

1000 

800 

600 

400 

200 

0 

* 21.5; 30.5 AgAlO2 

Z-Ag 

* 

0 

6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 

2 theta 

* 

natural zeolite 

Fig. 2. X-ray diffraction patterns of the natural zeolite and 

of the Ag-doped zeolite 

The intensities of reflection observed at about 

10°, 23°, and 30° corresponding to the clinoptilolite 

amount decreased due to the thermal treatment of Ag 

1200 

1000 

800 

600 

400 

200 

542

- doped zeolite (Rivera-Garza et al., 2000). 

No major differences in the diffraction patterns 

were observed due to de presence of the low amount 

of silver into zeolite. However, traces of AgAlO 2 

(21.5°; 30.5°) were identified. 

Figs 3a and 3b illustrates the SEM images of 

natural and thermally treated Ag-doped zeolite. 

Obtaining and characterization of Romanian zeolite supporting silver ions 

a) 

Fig. 3a. SEM image of the natural zeolite 

b) 

Fig. 4. AFM image of the Ag – doped zeolite: a) without 

thermal treatment; b) treated thermally at 500°C 

Fig. 3b. SEM image of Z-Ag 

Significant changes of the morphology of Agdoped 

zeolite in relation to the natural zeolite were 

shown in Figs. 3a and 3b, some small particles 

agglomerated on the zeolitic material were observed 

(Fig. 3b). 

AFM was used to provide complementary 

information from both the internal and external 

structure of natural and Ag – doped zeolite and to 

image Ag particles located within the structure of 

zeolite. The natural zeolite consisted of particles with 

diameters ranged between 102.7 and 307.9 nm (Orha 

et al., 2007) and AFM image of thermal 

untreated/treated Ag - doped zeolite showed the 

existence of smaller particles ranged between 106.9 

and 160.9 nm (Figs. 4a and 4b). With the existence of 

smaller particles (nanocrystals) the specific surface 

area increased, which means that the precipitation of 

silver oxide on the zeolite surface was avoided. 

The IR spectra of the thermally treated Agdoped 

zeolite sample (Z-Ag) and untreated (Agmodified 

Z) were compared with the IR spectrum of 

natural zeolite (Z), and are presented in Fig. 5. 

Fig. 5. IR spectra of natural zeolite (Z), silver doped zeolite 

(Z-Ag) and silver modified zeolite (Ag modified-Z) 

The influence of thermal treatment on Ag - 

doped zeolite was clearly observed especial for the 

vibration bands in the range between 3000 and 4000 

cm -1 . Taking into account the literature data (Rivera- 

Garza et al., 2000; Rodriguez-Fuentes et al., 1998) the 

assignation of vibration bands shown in Table 2 can 

be proposed for the Romanian zeolite from Mirsid. 

543

Orha et al. /Environmental Engineering and Management Journal 6 (2007), 6, 541-544 

The influence of both Ag cation and thermal 

treatment on the IR vibration is gathered in Table 3, 

and it can be underlined that the shoulder at 1205 cm - 

1 corresponding the internal tetrahedral asymmetric 

stretching disappeared in the presence of silver. Also, 

small changes related to the transmittance intensity of 

the vibration bands at 456 cm -1 , 1053 cm -1 in the 

presence of Ag cation were found out. The changes of 

the vibration bands, i.e., internal tetrahedral bending 

and internal tetrahedral asymmetric stretching in the 

presence of Ag gave information about the Ag 

incorporation into zeolite lattice. 

Table 2. The vibration bands for Romanian natural zeolite 

from Mirsid 

Vibration modes Wavenumber [cm -1 ] Intensity 

Internal tetrahedral 

bending 

456 strong 

External tetrahedral 

double ring 

604 medium 


linkage symmetric 791 weak 

stretching 


linkage asymmetric 1053 strong 

stretching 

Internal tetrahedral 

asymmetric stretching 

1205 shoulder 

O-H bending 1650 wide 

Table 3.The transmittance values at each wave number for 

unmodified/modified zeolite 

Sample T 1650 (%) T 1205 (%) T 1053 (%) T 791 (%) T 604 (%) T 456 (%) 

Natural 

zeolite 

60.7356 25.014 6.72181 68.6638 42.8188 18.0681 

Ag 

doped 58.6873 - 1.97174 63.8796 36.7916 8.58711 

zeolite 

Z-Ag 81.0015 - 23.1584 81.0711 71.9144 38.5474 


The ion exchange total capacities of natural 

and sodium forms of zeolite from Mirsid, Romania 

with the dimension of pores ranged between 0.8-1.2 

mm for silver depended slightly on the zeolite form 

(natural or Na-form). 

The presence of Ag into zeolite was identified 

by LIBS and the quantitative assessment of Ag 

modified zeolite obtained for its use in water 

disinfection was achieved by ICP-AES, the Ag 

amount incorporated into zeolite lattice was 0.0065 

mg/g zeolite. Ag amount incorporated into zeolite 

was about twenty times smaller than ion exchange 

total capacity of the zeolite for silver, this aspect 

being suitable for its use as antibacterial material due 

to the avoiding of undesired precipitation of silver 

oxide on zeolite surface. 

The comparative characterization of natural 

and Ag - doped zeolite performed by XRD proved the 

trace existence of AgAlO 2 form into the zeolite 

lattice. 

The existence of smaller particles in the 

presence of Ag proved by the structural 

characterization provided by SEM and AFM showed 

the specific surface area increasing of the Ag doped 

zeolite. The changes of internal tetrahedral bending 

and internal tetrahedral asymmetric stretching 

vibration bands of IR spectrum supported the Ag 

incorporation into zeolite lattice. 

Acknowledgements 

The structural analyses were made by co-operation 

with University of PECS, Institute of Physics and Laser 

Spectroscopy within the framework of the Romanian - 

Hungarian bilateral scientific research Project RO-Hu- 

20/2002 – 2005. This study was supported by the Romanian 

National Research of Excellence Programs-CEEX, Grant 

631/03.10.2005 - PROAQUA and 115/01.08.2006 

SIWMANET. 

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D., Rodriguez-Fuentes G., (2000), Silver supported 

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Materials, 20, 269-281. 

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Woinarski A. Z., Stevens G. W., Snape I., (2006), A natural 

zeolite permeable reactive barrier to treat heavy-metal 

contaminated waters in Antarctica: kinetic and fixedbed 

studies, Process Safety and Environmental 

Protection, 84, 109-116. 

544




______________________________________________________________________________________________ 

USING GPS TECHNOLOGY AND DISTRIBUTED MEASUREMENT 

SYSTEM FOR AIR QUALITY MAPING OF REZIDENTIAL AREA 

Alexandru Trandabăţ 1∗ , Marius Branzila 1 , Codrin Donciu 1 , 

Marius Pîslaru 2 , Romeo Cristian Ciobanu 1 

1 Technical University of Iasi, Faculty of Electrical Engineering, 51-53 Mangeron Blvd., 700050, Iasi, Romania 

2 Technical University of Iasi, Dept. of Management and Engineering of Production Systems, 53 Mangeron Blvd., 700050, Iasi, 

Romania 

Abstract 

The project’s idea is really simple: using the LabView environment, we have realized a virtual instrument able to get from the 

GPS the information about latitude, longitude, altitude and from a prototype data acquisition board for environmental monitoring 

parameters the information about air pollution factors. The perfect solution regarding the costs, the covered area and the accuracy 

of the measured data is the use of a glider for flight, because of its characteristics: free flights (without engine – meaning no local 

air polluting source), mobility (it is able to cover in one flight hundreds of kilometers) and low cost maintenance. 

All the information obtained during the measurement flights are corroborate with the meteorological information obtained from 

the local automatic meteorological station This mapping system can be used to map the information about the air pollution factors 

dispersion in order to answer to the needs of residential and industrial areas expansion. 

Key words: Virtual Instrumentation, Distributed Measurements, GPS, Air Quality Assurance 


The atmospheric environment needs to be 

examined in consideration of the following three 

phenomena: global warming, ozone-layer depletion, 

air pollution. 

Among these three, global warming is the 

most critical in terms of environmental conservation. 

Global warming is a result of greenhouse-gas 

emissions; therefore, to prevent it, greenhouse-gas 

emissions must be reduced. A major greenhouse gas 

is carbon dioxide (CO2). Therefore, reducing energy 

use, or saving energy, is the most effective way to 

help prevent global warming. There are some other 

gases that have a considerable influence on global 

warming. The first step to cutting the emissions of 

these gases as another environmental conservation 

measure is to monitor them in order to find a way to 

control those (Branzila et al., 2004). 

The decisions related to the environment 

safety are often taken in the belief that they are 

scientifically well founded, i.e. by placing an 

excessive faith in the reliability of the expert 

information on which they are based. But, during the 

last century, such a pursuit was denied by an alarming 

number of environmental injuries, causing a 

continuously growing societal concern. 

Today – more than ever – the public demands 

credible and understandable information about the 

quality of the environment in which they live or work 

the trend of environmental indicators, the priority 

problems related to environment pollution and long 

term associated risks. Accordingly, the common 

uncertainty and/or ignorance in decision-making AIR 

QUALITY AND POLLUTION MAPPING SYSTEM 

317 must be balanced by innovative and 

multidisciplinary methods in order to carry out an 

efficient exchange of information across the different 

sectors and aspects involved in environmental 

monitoring (Trandabat and Pislaru, 2005). 

∗ Author to whom all correspondence should be addressed: ftranda@ee.tuiasi.ro

Trandabat et al. /Environmental Engineering and Management Journal 6 (2007), 6, 545-548 

One of the main concerns is represented by the 

atmospheric environment, very sensitive to a synergy 

of factors, as consequence of three phenomena: global 

warming, ozone-layer depletion and, above all, local 

air pollution. Among all, global warming is the most 

critical in terms of environmental conservation, a 

clear result of greenhouse-gas emissions excess, 

mainly carbon dioxide (CO2). Nevertheless, the first 

step towards environment quality conservation lies in 

monitoring efficiently the factors with potential risk 

at local dimension. The actual practice clearly 

demonstrated that the classical, local, static 

measurements are affected by uncertainties, even 

errors. These uncertainties are propagated through the 

models of complex systems and finally presented in 

some form to the decision-maker, with tragic 

consequences. Therefore, the need to revise the 

existing models by checking their compatibility with 

the precautionary principle of vertical and dynamic 

monitoring represents a must for the novel reliable 

measurement systems. Such an example is offered by 

the remote measurement system described below. 

so it is limited to three hours of continuum 

monitoring (Schreiner et al., 2006). 

2. The system architecture 

The main objective of this work is to realize a 

complex device for environmental quality control and 

monitoring. The system consists of two main parts: 

the mobile and the field component (Fig. 1). In order 

to cover a large monitoring area, the mobile system is 

placed on the luggage compartment of a glider. In the 

free flight, the glider will cover a wide area, and 

caring the mobile part of the system assures a good 

measurement precision without polluting the 

monitoring site with the exhaust gases, as a motorized 

aircraft would. 

The mobile part is compound from an 

acquisition block based on specialized sensors 

connected in a low cost prototype acquisition board, 

from a positioning system which is represented by a 

GPSmap 196, a laptop and a transmission module. 

The software platform for this project was developed 

in Labview programming environment (Trandabat 

and Branzila, 2005). 

The communication between GPS and laptop 

is realized with RS232 interface, using the NMEA 

protocol. The recorded data from GPS on the 

database are the values corresponding to the 

longitude, latitude and altitude, and separately, for a 

further complex data analyze, the values for speed. At 

the same time, the database receives also the values 

for the monitored gases concentration through a 

parallel port from the acquisition prototype board 

where the sensors are connected. If the monitored 

value is discovered to be out of the normal values, the 

communication module is activated and a warning 

message with the position and the recorded value is 

sent using a normal GPRS mobile phone to the field 

base, from where the responsible authorities are 

informed. 

On this stage of the project, the mobile system 

autonomy depends on the laptop accumulator power, 

Fig. 1. The system for on-line environmental monitoring 

using a prototype data acquisition board, GPS and GPRS 

technology 

On the ground station, the database is 

downloaded at the end of the flight in order to be 

analyzed. The data from the database are corroborated 

with the information picked up during the day from 

the automatic meteorological weather station. The 

aim of this analyzes is to realize an air quality map 

for the monitored site (Fig. 2). 

For common communication procedure 

between the measurement point assisted by a laptop 

and the server, DataSoket communication and TCP/IP 

tools were preferred. The expert user from the ground 

has the possibility to visualize the real data and/or to 

analyze the environmental quality factors via a 

history diagram stored in the server database (Girao et 

al., 2003). 

The bloc diagram of the server virtual 

instrument is presented in Fig. 2. All communication 

software is designed under LABVIEW graphical 

programming language as well, including three 

protocol types. Communication type PC-instruments 

is developed using GPIB protocol, PC-server using 

TCP/IP and Internet communication using data socket 

technology, as is presented in Fig. 1. 

546

Using GPS technology and distributed measurement system 

complement format it is stored in an internal 32-word 

(16-bit wide) FIFO data buffer (figures 3 and 4). An 

internal 8- word RAM can store the conversion 

sequence for up to eight acquisitions through the 

LM12H458CIV’s eight-input multiplexer. The 

LM12H458CIV operates with 8-bit + sign resolution 

and in a supervisory “watchdog” mode that compares 

an input signal against two programmable limits. 

Fig. 2. Example of 3D air quality map; with dark red - the 

major risk area 

3. Detection circuit and data acquisition board 

In our application, dedicated sensors for 

temperature and gas evaluation (sensing element - 

metal oxide semiconductor, mainly composed of 

SnO2) for air quality analysis were used. In principle, 

mainly the gas sensors should be of highest quality, 

because they should offer immediate pertinent 

information towards defining representative 

environmental indicators, allowing evaluation of 

trends and quantification of achieved results in 

connection with temporal (season, day/night, peak 

hours etc.) or geographical parameters (altitude, 

vicinity etc.), or to atmospheric conditions (humidity, 

wind etc.), or even to societal demands (residential or 

industrial areas). The sensing element is heated at a 

suitable operating temperature by a built-in heater, 

allowing a sensitive change in its electrical resistance. 

In pure air, the sensor resistance is high, but, when 

exposed to a variety of gases, the sensor resistance 

decreases selectively in accordance with the gas type 

and concentration. Based on this information, the 

expert system from ground server processes the data 

according to a statistical – pollution (contamination) 

process - control methodology, decrypting the gases 

type and concentration and mapping the potential risk 

for environment safety (Branzila et al., 2005). 

On the basic detection circuit, the change in 

the sensor resistance is obtained as the change of the 

output voltage across the load resistor (RL) in series 

with the sensor resistance. The constant 5V output of 

the data acquisition board is available for the heater 

of the sensor (VH) and for the detecting circuit (VC). 

As already indicated, the LM12H458CIV chip was 

preferred to make a Data Acquisition Board for 

interfacing with the laptop by parallel port and realize 

a flexible and complex system to allow monitoring of 

environmental parameters via some detection circuits 

with gas sensors distributed around the glider. The 

data acquisition board is related to highly integrated 

DAS. Operating on just 5V, it combines a fully 

differential self-calibrating (correcting linearity and 

zero errors) 13-bit (12-bit + sign) analogue to digital 

converter (ADC) and sample-and-hold (S/H) with 

extensive analogue functions and digital functionality. 

Up to 32 consecutive conversions using two’s 

Fig.3. Architecture of prototype data acquisition board, 

through parallel port of PC 

Programmable acquisition times and 

conversion rates are possible through the use of 

internal clock-driven timers. The reference voltage 

input can be externally generated for absolute or 

ratiometric operation or can be derived using the 

internal 2.5V bandgap reference. All registers, RAM, 

and FIFO are directly addressable through the highspeed 

microprocessor interface to either an 8-bit or 

16-bit databus. The LM12H458CIV include a direct 

memory access (DMA) interface for high-speed 

conversion data transfer (Branzila et al., 2004). 


The paper presents the architecture of a 

versatile, flexible, cost efficient, high-speed 

instrument for either monitoring the air quality and/or 

mapping the air pollution. The concept is based on a 

remotely controlled acquisition part - placed in a 

glider - with distributed and virtually programmed 

gas sensors, and a local dedicated expert system. The 

system may be particularized as virtual laboratory for 

on-line environmental monitoring classes too, helping 

the formation of well trained specialists in the 

domain. The immediate potential application lies in 

mapping the air pollution in terms of: factors, 

dispersion, trend, evolution and causes identification, 

in order to answer to the needs of immediate action 

and/or residential and industrial areas sustainable 

expansion, very important problems met mainly by 

candidate countries to EC. 

547

Trandabat et al. /Environmental Engineering and Management Journal 6 (2007), 6, 545-548 

References 

Branzila M., Temneanu M. ,Creţu M, Pereira M.D., Donciu 

C., (2004), System for environmental monitoring 

using a data acquisition board by parallel port, IPI, L, 

737-742. 

Branzila M., Fosalau C., Donciu C., Cretu M., (2005), 

Virtual Library Included in LabVIEW Environment 

for a New DAS with Data Transfer by LPT, Proc. 

IMEKO TC4 , vol.1, Gdynia/Jurata Poland, 535-540. 

Girao P., Postolache O., Pereira M., Ramos H., (2003), 

Distributed measurement systems and intelligent 

processing for water quality assessment, Sensors & 

Transducers Magazine, 38, 82-93. 

Schreiner C., Branzila M., Trandabat Al., Ciobanu R., 

(2006), Air quality and pollution mapping system, 

using remote measurements and GPS technology, 

Global NEST Journal, 8, 315-323. 

Trandabat A., Branzila M., Schreiner C., (2005), 

Distributed measurements system dedicated to 

environmental safely, Proc. 4th Int. Conf. on the 

Manag. of Tech. Changes, vol.2, Chania-Greece, 121- 

124. 

Trandabat A., Pislaru M., Schreiner C., Ciobanu R., (2005), 

E-survey instruments based on remote measurements 

dedicated to peculiar areas with increased risk for 

environmental safety, 9th Int. Conf. on Environmental 

Science and Technology, Vol. B, Rhodes-Greece, 

933-938. 

548




______________________________________________________________________________________________ 

SYNTHESIS, CHARACTERIZATION AND CATALYTIC REDUCTION OF 

NO x EMISSIONS OVER LaMnO 3 PEROVSKITE 

Liliana-Mihaela Chirilă 1∗ , Helmut Papp 2 , Wladimir Suprun 2 , Ion Balasanian 1 

“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering 

and Management, 71A D. Mangeron Bd., 700050 - Iasi, Romania 

2 Institute for Technical Chemistry, University of Leipzig, Linnéstr. 3, D-04103 Leipzig, Germany 

Abstract 

The perovskite structure was synthesized by sol-gel method type citrate. Three perovskite LaMnO 3 samples were obtained after 

calcination and were characterized by XRD, XPS and TPR. The catalytic testing was carried out in SCR-HC equipment 

(HC=C 3 H 6 and C 3 H 6 respectively) in presence and also in absence of oxygen atmosphere. The results pointed out a good activity 

in NO x reduction but only in oxygen absence. As it was expecting, LaMnO 3 perovskite has shown a good activity for 

hydrocarbons oxidation 

Key words: citrate sol-gel, perovskites, SCR-HC 


Once the atmosphere pollution became a 

serious problem for environment, the scientific world 

in the field started to develop different methods for 

removing of emissions resulted from human 

activities. It is well known that a large amount of 

nitrogen oxides emissions are coming from lean burn 

engines. 

Selective catalytic reduction (SCR) method of 

nitrogen oxides supposes the using of reduction agent 

which increases the requirements for mobile engines. 

Thus, for catalytic nitrogen oxides converting the 

attention was headed to the burn environment for a 

proper reduction agent. Many tests were used the 

hydrocarbons as reduction agent leading to good 

results of nitrogen oxides conversion (Buciuman et 

al., 2001; Haj et al., 2002; Rottländer et al., 1996; 

Tran et al., 2004). 

Another problem in selective catalytic 

reduction is the catalyst choosing. A good catalyst 

must have a high stability, a high catalytic activity 

and to be cheap. A good catalytic potential for 

nitrogen oxides removing has shown different 

catalytic materials such noble metals, zeolites or 

oxides. The exotic character of some oxides with 

perovskite structure is reflecting in their catalytic 

activity and makes them famous in oxidation catalytic 

processes. Different results were obtained in catalytic 

reduction over these structures (Ng Lee et al., 2001; 

Patcas et al., 2000; Spinicci et al., 2003). 

The aim of this paper is synthesis and 

characterization of LaMnO 3 perovskite and its testing 

as catalytic material in nitrogen oxides removing by 

SCR-HC method. Three LaMnO 3 perovskite samples 

were obtained by calcinations at 600, 800 and 1000 

o C and were characterized by XRD, XPS, gas 

physisorbtion and TPR. The catalytic testing of these 

samples was carried out in SCR-HC equipment where 

the hydrocarbons used like reduction agent were 

propene and propane. 


2.1. LaMnO 3 synthesis 

LaMnO 3 perovskite structure was prepared by 

citrate method type sol-gel using lanthanum and 

manganese nitrates 1:1 with an excess of citric acid 

1.5. It was followed next steps of the perovskite 

synthesis: i) stirring of precursors in distilled water at 

60 o C till obtaining a yellow viscous solution; ii) 

∗ Author to whom all correspondence should be addressed: lchirila@ch.tuiasi.ro

Chirila et al /Environmental Engineering and Management Journal 6 (2007), 6, 549-553 

drying in oven at 80 o C and iii) calcination in muffle 

oven of the dried gel at three different temperatures: 

600, 800 and 1000 o C (5 hours for each sample). 

2.2. Characterization 

The calcined solids were characterized by 

different methods: X-ray diffraction (XRD), X-ray 

photoelectron spectroscopy (XPS), gas physisorbtion 

(N 2 ) and temperature programmed reduction (TPR). 

The crystallographic data were obtained using 

a Siemens D5000 diffractometer with CuKα radiation 

for crystalline phase detection between 5 and 100 o 

(2θ). XPS surface analysis were performed with a 

LHS 10 (Leybold AG) spectrometer using MgKα 

radiation (λ = 1256.6 eV). The specific surface area 

(BET) was determined by nitrogen adsorption at 300 

o C using a Micrometics model ASAP 2000. TPR 

analysis was carried out under H 2 atmosphere, in a 

temperature range between 30 and 900 o C. 

2.3. Catalytic activity testing 

The catalytic reduction of nitrogen oxides was 

carried out in a SCR-HC equipment with a gas 

mixture consisted by hydrocarbon (C 3 H 6 – 600 ppm 

and C 3 H 8 -800 ppm respectively), nitrogen oxides 

(600 ppm) under rich oxygen atmosphere (5%). 


3.1. The characterization of LaMnO 3 perovskite 

samples: XRD, XPS, gas physisorption and TPR 

In order to assess the perovskite-like structure, 

XRD analysis was recorder. The diffractograms 

obtained for LaMnO 3 perovskite samples are shown 

in Fig.1. The strong line of each XRD pattern showed 

the presence of single perovskite phase. In accordance 

with JCPDS-1998 data, all synthesized samples 

correspond to perovskite structure as is presented in 

Table 1. 

1000 °C 

800 °C 

600 °C 

0 10 20 30 40 50 60 70 80 90 

2 Theta 

Fig.1. X-Ray diffractograms of LaMnO 3 perovskites 

calcined at 600, 800 and 1000 o C, respectively 

It was found a full perovskite structure like 

LaMnO 3 for the synthesized sample at 600 o C while 

the synthesized sample at 800 o C has shown a 

lanthanum deficit of perovskite structure. An oxygen 

excess in the perovskite structure has shown the last 

sample, synthesized at 1000 o C. 

Table 1. The samples correspondence with perovkite 

structure 

Samples 

Perovskite JCPDS-1998 Symmetry 

structure 

600 o C LaMnO 3 86-1234, 75-440 Cubic 

800 o C La 0.92 MnO 3 82-1152 Rhombohedra 

1000 o C LaMnO 3+δ 32-848 Hexagonal 

These deviations from the perfect stoichimetry 

result from calcinations process when the perovskite 

phase is under transformation. Alongside with the 

temperature increasing, the crystallographic structure 

is changing due to octahedral distortion. 

For all perovskite synthesized samples, the La 

3d 5/2 signal it was found around 833,6 eV. The Mn 

2p 3/2 binding energy is 640 eV for LaMnO 3 structure 

and 641 eV for the others that showing the presence 

of Mn(III) in perovskite structure of the samples 

synthesized at 800 and 1000 o C. O 1s signal was 

appeared in three peaks typically corresponding to 

binding oxygen, the oxygen from hydroxyl or 

carbonate and oxygen from humidity. 

The values of surface atom composition are 

presented in Table 2 and showed enrichment in 

lanthanum of the perovskite surface for all analyzed 

samples. 

Table 2. Surface atom composition, BET surface area and 

reduction degree 

Atom % 

T cal. 

BET 

Mn La O 1s 

°C 

(m 2 /g) 

I II II 

600 15,4 20,4 41 18,6 4,6 24,7 

800 15,1 20,2 39 18,7 7 13,1 

1000 15 21 39 19,4 6 2,4 

BET surface area (m 2 /g) has values which 

decrease parallel with increasing of calcination 

temperatures at which the samples were obtained. 

Thus, sample obtained at 600 o C have higher value 

while the less value is given by surface of the sample 

calcined at 1000 o C, Table 2. 

TPR shape is given by reduction behavior of 

manganese oxides in analyzed perovskite in the 

presence of reducing gas, behavior very important 

which is reflected in catalytic activity of whole 

structure. 

In order to characterize resulted MnOx phases 

during synthesis of perovskite, it has to take into 

account that Mn 4+ reduces at lower temperature (331- 

351 o C) than Mn 3+ (443-526 o C) (Buciuman et. al., 

2000; Stephan et. al., 2002). TPR curves of three 

LaMnO3 perovskite samples presented in Fig. 2 are 

characterized by two reduction regions. 

550

Syntheis, characterization and catalytic reduction of NOx emissions over LaMnO 3 perovskite 

60 

(c) 

50 

(b) 

(a) 

0 200 400 600 800 1000 

Conversia NO x 

[%] 

40 

30 

20 

10 

600 °C 

800 °C 

1000 °C 

Temperature (°C) 

0 

150 200 250 300 350 400 450 500 550 600 650 

Fig. 2. TPR curves for three LaMnO 3 perovskite samples 

calcined at 600, 800 and 1000 o C, respectively 

100 

Temperatura [°C] 

The first region corresponds to manganese 

oxides reduction, already discussed, reduction that 

gradually takes place as the corresponding 

temperature peaks show. The first peak corresponds 

to Mn 4+ la Mn 3+ reduction when reduction performs 

between 78 331-351 o C, followed by Mn 3+ la Mn 2+ 

reduction ate temperatures comprised between 421- 

471 o C. The high consuming oh hydrogen happens in 

the second region of reduction curves due to both, 

Mn 3+ reduction to Mn 2+ in LaMnO 3 perovskite and 

carbonate species such as La 2 O 2 CO 3 those reduction 

corresponds to this temperature interval. Considering 

that these perovskites were prepared by citric method 

it is very plausible that carbonates traces are in their 

structure (Hackenberger, 1998; Stephan et. al., 2002). 

3.2. Catalitic activity testing SCR-C 3 H 6 

The perovskite samples were tested in nitrogen 

oxides removing by SCR-C 3 H 6 in presence and also 

in absence of oxygen atmosphere. In oxygen 

atmosphere (5%), the experimental results indicated 

of 100% propene oxidation activity between 300 and 

450 o C for the samples obtained at 600 and 1000 o C 

while for sample obtained at 800 o C, the maxim 

activity was around 78% after which the oxidation 

activity had kept just below this value. 

The maxim point of propene conversion 

corresponded to the temperature interval in which 

propene could decompose to carbon dioxide and 

water. The perovskite synthesized sample at 1000 o C 

achieved maximal activity at 300 o C then it sharply 

deactivated. Regarding nitrogen oxides reduction as it 

can be seen in the experimental data processing (Fig. 

3) all three LaMnO 3 perovskite samples practically 

showed negligible conversion values. 

The tests performed on synthetic gas mixture 

without oxygen have shown high activity for propene 

oxidation process but these were moved on high 

temperature range, over 400 o C. 

Conversia C 3 

H 6 

[%] 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

600 °C 

800 °C 

1000 °C 

150 200 250 300 350 400 450 500 550 600 650 


Fig. 3. Nitrogen oxides (a) and propene (b) conversin for 

the LaMnO 3 perovskite samples (propene 600 ppm, NOx 

600 ppm, 5% O 2 ) 

For LaMnO 3 perovskite sample obtained at 

600 o C the catalytic activity test was carried out on a 

large temperatures range between 150 and 600 o C. 

Therefore, it can be observed for this sample that 

oxidation activity becomes maxim over 500 o C and it 

remains constant until 600 o C, experimental limit 

temperature. The other two perovskites samples, 

synthesized at 800 and 1000 o C, the values of 

nitrogen oxides conversion was increasing until 

ending of experiment, 450 o C. At this temperature, 

LaMnO3 sample calcined at 800 o C presents the 

higher value (100%) while sample calcined at 1000 o C 

has the lower catalytic activity (65.24%) (Fig. 4). 

3.3. Catalytic activity testing SCR-C 3 H 8 

Data processing obtained in selective catalytic 

reduction of nitrogen oxides using propane as 

reduction agent with 5% oxygen in synthetic gas 

mixture has led to the curves grouped in Fig.5. In this 

case, oxidation reaction reaches maximal values at 

high temperatures interval (350-450 o C). As it is 

shown in Fig. 5 diagram b, the LaMnO 3 perovskite 

samples achieve maximal hydrocarbon conversion 

point at 450 o C. 

551

Chirila et al /Environmental Engineering and Management Journal 6 (2007), 6, 549-553 


[%] 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

600 °C 

800 °C 

1000 °C 

150 200 250 300 350 400 450 500 550 600 650 

Oxygen lack in synthetic gas mixture leaded to 

important changes of conversion curves for both 

propane oxidation and nitrogen oxides reduction. 

Fig.6 displays, reduction reaction was favored, while 

oxidation reaction has kept constant values in whole 

temperature range in which tests were performed. The 

higher values for oxidation reaction belong to 

perovskite sample calcined at 600 o C which proves to 

be again the most efficient perovskite in propane 

oxidation while LaMnO 3 sample calcined at 800°C 

presented lower values, almost negligible. 


100 

100 

90 

90 

80 

Conversia C 3 

H 6 

[%] 

80 

70 

60 

50 

40 

30 

20 

10 

0 

600 

800 

1000 

150 200 250 300 350 400 450 500 550 600 650 


Conversiea NO x 

[%] 

70 

60 

50 

40 

30 

20 

10 

0 

600 

800 

1000 

150 200 250 300 350 400 450 

Temperature [°C] 

Fig. 4. Nitrogen oxides (a) and propene (b) conversion for 

the LaMnO 3 perovskite samples (propene 600 ppm, NOx 

600 ppm) 


[%] 

Conversia C 6 

H 8 

[%] 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

600 °C 

800 °C 

1000 °C 

150 200 250 300 350 400 450 


600 °C 

800 °C 

1000 °C 

150 200 250 300 350 400 450 


Fig. 5. Nitrogen oxides (a) and propane (b) conversion for 

the LaMnO 3 perovskite samples (propane 400 ppm, NOx 

600 ppm, 5% O 2 ) 

Conversia C 6 

H 8 

[%] 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

600 °C 

800 °C 

1000 °C 

150 200 250 300 350 400 450 


Fig. 6. Nitrogen oxides (a) and propane (b) conversion for 

the LaMnO 3 perovskite samples (propane 400 ppm, NOx 

600 ppm) 


The characterization by presented physicochemical 

methods confirmed that the synthesized 

samples are perovskite structures with a high 

homogeneity and crystallinity. The calcination 

process has leaded to three different symmetry of 

LaMnO 3 perovskite due to octahedral distortion. 

It is well known that perovskites present a 

certain small surface comparing with other catalysts. 

The BET specific surface of LaMnO 3 perovskite was 

found 24m 2 /g corresponding to the sample obtained at 

600 o C and decreases once with the calcinations 

temperature rising up to 2.5m 2 /g in the case of 

calcinations sample at 800 o C. The oxidation state of 

the manganese from the LaMnO 3 perovskite leaded to 

552

Syntheis, characterization and catalytic reduction of NOx emissions over LaMnO 3 perovskite 

a reducing character just like the reduction analysis at 

programmed temperature showed. 

The catalytic activity tests made on the three 

LaMnO 3 perovskite samples using propena and 

propan as reduction agent, showed a good oxidation 

catalytic activity in a rich oxygen medium. For lack 

of oxygen from the synthetic mixture of gas using 

propane, the LaMnO 3 perovskite presents activity 

both in nitrogen oxides reduction and the propane 

oxidation. In the case of propane the oxidation 

activity takes place only in the presence of oxygen, 

while the reduction activity needs a poor oxygen 

medium and over 400 o C temperatures. For the 

temperature interval of 150 o -450 o C used in catalytic 

activity tests the “full” structure type LaMnO 3 had the 

best activity. A good activity was obtained also in the 

case of the other two types of structures: La 0.98 MnO 3 

and LaMnO 3.15 . Using propene as a reduction agent 

leads to better results than using propane. The 

synthesized sample at 800 o C revealed the lowest 

activity in nitrogen oxides reduction with propene in 

lack of oxygen 

References 

Hackenberger M., (1998), Untersuchungen an Perowskit – 

Katalysatoren und Perowskit-Traegerkatalyzatoren 

fuer die Totaloxidation von Schadstoffen, 

Dissertation, Universität Leipzig, Germany. 

Alifanti M., Kirchnerova J., Delmon B., (2003), Effect of 

substitution by cerium on the activity of LaMnO 3 

perovskite in methane combustion, Appl. Cat. A: 

Gen., 245, 231-244. 

Buciuman F. C., Patcas F., Zsakó J., (2000), TPR-study of 

Substitution Effects on Reducibility and Oxidative 

Non-stoichiometry of La0.8A'0.2MnO3+δ 

Perovskites, Journal of Thermal Analysis and 

Calorimetry, 61, 819-825. 

Buciuman F. C., Joubert E., Menezo J. C., Barbier J., 

(2001), Catalytic properties of La 0.8 A 0.2 MnO 3 (A = Sr, 

Ba, K, Cs) and LaMn 0.8 B 0.2 O 3 (B = Ni, Zn, Cu) 

perovskites: 2. Reduction of nitrogen oxides in the 

presence of oxygen, Appl. Cat. B: Env., 35, 149-156. 

Kakihana M., Arima M., Yoshimura M., Ikeda N., Sugitani 

Y., (1999), Synthesis of high surface area LaMnO 3+d 

by a polymerizable complex method, J. Alloys. 

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553

554




______________________________________________________________________________________________ 

KINETICS OF CARBON DIOXIDE ABSORPTION INTO AQUEOUS 

SOLUTIONS OF 1, 5, 8, 12- TETRAAZADODECANE (APEDA) 

Ilie Siminiceanu 1∗ , Ramona-Elena Tataru-Farmus 1 , Chakib Bouallou 2 

1 Technical University “Gh. Asachi” of Iaşi, Faculty of Chemical Engineering, 71 Bd. Mangeron, RO- 700050 Iaşi, Romania 

2 Ecole Nationale Supérieure des Mines de Paris, Centre d’Energétique (CENERG), 60 Bd. Saint Michel, 75006 Paris, France 

Abstract 

The absorption of CO 2 into an aqueous solution with 1.45 mol/L 1,5,8,12-tetraazadodecane (APEDA) polyamine has been studied 

at three temperature (298, 313, 333 K) in a Lewis type absorber with a constant gas-liquid interface area of (15.34 ± 0.05) x 10 -4 

m 2 . The experimental results have been interpreted using the equations derived from the two film model with the assumption that 

the absorption occurred in the fast pseudo- first- order kinetic regime. The results confirmed the validity of this assumption for the 

experimental conditions: the enhancement factor was always greater than 3. The rate constant derived from the experimental data 

(k ov , s -1 ) was correlated through the Arrhenius plot ( ln k ov = A- B/T), and the optimal values of the constants A and B were 

obtained by the linear regression. The absorption of CO 2 from flue gas into APEDA solution is a promising process for practical 

application at least from the kinetic point of view. The rate constant derived from experiments is of the same order of magnitude 

as that for the absorption into 2- amino- 2- methyl- 1- propanol (AMP) activated with piperazine (PZ) which was found to be the 

most advanced system among the published data up to now. 

Key words: acid gas absorption, Lewis cell absorber, enhancement factor, rate constant 


The removal of carbon dioxide from gas 

streams by selective absorption into aqueous solutions 

is an important industrial process in both natural gas 

sweetening and ammonia synthesis gas production. 

Aqueous hot potassium carbonate promoted by 

diethanolamine (DEA) is the chemical solvent used in 

the ammonia plants of Romania. Today, there are 

seven such ammonia plants in Romania (each of 1000 

t NH 3 / day) where the absorption is operated at 30- 40 

bar, 343 K, solution with 25- 30 % K 2 CO 3 and 1-2 % 

DEA, in packed columns. The carbon dioxide, 

recovered by the reverse reaction (1) in the stripping 

column, is then consumed in the reaction (2) with 

ammonia, to produce urea- the best nitrogen fertilizer 

(Siminiceanu, 2004). 

CO 2 + K 2 CO 3 + H 2 O = 2 KHCO 3 (1) 

CO 2 + 2 NH 3 = CO (NH 2 ) 2 + H 2 O (2) 

The question is: could be this process 

applied with the same high performances as in 

ammonia production to the capture of carbon dioxide 

from combustion flue gas of the fossil fuel power 

plants? Unfortunately, the answer is no. This is 

because the flow rates, composition, temperature and 

pressure of flue gas are different. The CO 2 partial 

pressure in the flue gas is much lower then in 

ammonia synthesis gas. It is of maximum 15 kPa. 

Therefore, more reactive absorbents are needed, like 

monoethanolamine (MEA) aqueous solution. The 

absorption of CO 2 into MEA solution is also a well 

established process (Kohl and Nielsen, 1997). It has 

been already applied in the only three industrial plants 

in the world for CO 2 capture from fossil fuel power 

plant flue gas (Abu- Zahra et al., 2007a; 2007b). They 

have the commercial names Econamine FG, 

Econamine FG Plus, and ABB Lumnus, respectively. 

The simplified flow diagram of such a process is 

presented in Fig.1.After the removal of NO x and SO x 

∗ Author to whom all correspondence should be addressed: isiminic@ch.tuiasi.ro

Siminiceanu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 555-561 

the flue gases are cooled at 40 o C and transported with 

a gas blower to overcome the pressure drop caused by 

the MEA absorber. The MEA solution (30- 40 % 

MEA) is regenerated in the stripper at elevated 

temperatures (100- 120 o C) and a pressure not much 

higher than atmospheric. Heat is supplied to the boiler 

using low- pressure steam which also acts as a 

stripping gas. Besides the high absorption rate, the 

MEA process has a number of drawbacks that are 

detailed bellow. 

Fig. 1. Flow sheet of the CO 2 removal from flue gas by the 

MEA process 

(1) The first important drawback is the large 

absorption/stripping enthalpy: 83 kJ/mol CO 2 at 298 

K, in a solution 5M of MEA (Hilliard, 2005). This is 

equivalent to 4.0 GJ/t of CO 2 captured. The actual 

energy requirement in the Econamine FG process is 

of 4.2 GJ/t (Abu-Zahra et al., 2007a). The enthalpy of 

absorption of CO 2 into MEA solution is higher than 

in both K 2 CO 3 solution (63 kJ/ mol) and in other 

amine solutions (DEA, AMP, MIPA, PZ, MDEA). 

Therefore, the energy consumption of MEA capture 

system could be up to 40% of the power plant output 

(Hilliard, 2005) and a proportional more expensive 

electrical energy which must be peyed by consumers. 

Nevertheless, recently has been found (Dallos et al., 

2001) that the absorption enthalpy of CO 2 into a 

polyamine (TMBPA) is of only 44 kJ/mol. This 

suggested to the authors of this paper to study the 

absorption of CO 2 into a similar polyamine:1,5,8,12- 

tetraazadodecane (APEDA). 

(2) The second major drawback of MEA is the 

law cyclic absorption capacity. The theoretical value 

is of 0.5 mol CO 2 / mol amine, according to the 

overall reaction (3), based on the carbamate formation 

through the zwitterions mechanism: 

CO 2 + 2 HOCH 2 CH 2 NH 2 = HOCH 2 CH 2 NCOO - + 

HOCH 2 CH 2 NH + 2 (3) 

The practical value is of only 0.35 (from 0.2 of 

the lean solution to 0.45 of the carbonated 

solution).Therefore, the MEA process needs about 55 

m 3 solution /ton CO 2 captured. The polyamine named 

TMBPA has a saturation loading of 3 mol CO 2 / mol 

amine (Dallos et al., 2001). A higher cyclic capacity 

reduces the flow rate of the solution needed. APEDA 

is expected to have a cyclic absorption capacity of 2 

because it includes two primary and two secondary 

amine groups in the molecule (Table 1). 

(3). The third important disadvantage of MEA 

is its degradability. The reactions of MEA with NOx, 

SOx, CO and O 2 which accompany the CO 2 in flue 

gases leads to heat- stable salts which must be purged 

from the recalculated solution (Bello and Idem, 

2005). These salts mainly consist of formate (87%), 

acetate (4.6%), oxalate (0.2%), thiocyanate (6.8%), 

thiosulphate (1.2%) and sulphate (0.2%). The 

production of these salts could be from 3.729 to 

14.917 kg/ t CO 2 captured (Thitakamol et al., 2007). 

This means that up to 10% of active amine is lost 

through degradation. It must be noted that the 

degradation oxidative reactions of MEA begin by the 

attack at the alcohol function of the alkanol radical 

(Strazisar et al., 2003). The replacement of MEA with 

an alkyl amine could avoid or mitigate the 

degradation reactions. 

(4). The presence of heat- stable salts in the 

absorption solution causes a number of adverse 

effects: reduction of amine absorption capacity, 

increase in foaming tendency of the solution, increase 

in solution viscosity, increase in corrosion, reduced 

filter runtime due to the solid precipitation in 

solution. Consequently, the solution must contain at 

least three types of additives: oxygen scavengers 

(OS), corrosion inhibitors (CI), and antifoam agents 

{AA). The addition of OS is claimed to reduce the 

formation of heat- stable salts. Potential OS are: 

quinine, oxime, hydroxylamine and their mixtures. 

Corrosion inhibitors developed and patented include 

organic inhibitors (thiourea, salicylic acid) and 

inorganic inhibitors (V, Cr, Cu, Sb, S 

compounds).The inorganic CI has superior inhibition 

performance (Tanthapanichakoon, 2006). Sodium 

metavanadate (NaVO 3 ) is the most extensively used 

in amine treating plants for ammonia synthesis gas 

manufacture (Siminiceanu, 2004). Antifoam agents 

must also be used to reduce foam formation, which 

may occur due to the presence of fine solid particles 

and heat-stable salts. Common antifoam agents are 

high-boiling alcohols (Kohl and Nielsen, 1997) such 

as oleyl alcohol and octylphenoxyethanol, or siliconebased 

compounds such as amino silicon and 

dimetylsilicon. These special additives make the 

MEA solution an expensive one. The estimated cost 

of CO 2 capture by absorption in MEA solution was 

evaluated at EUR 39.3/ tone of CO 2 avoided (Abu- 

Zahra et al., 2007b). This could increase the cost of 

electricity production by 82.8 % (from EUR 

31.4/MWh to EUR 57.4/ MWh). APEDA is not an 

alakanolamine and could be not degraded by 

oxidation with SO x , CO and O 2 . In addition, APEDA 

is frequently used as ingredient for corrosion 

inhibitors (http://www.chemicalland21.com/arokorhi/ 

specialtychem/finechem/) 

The objective of this work was to study the 

kinetics of CO 2 absorption into APEDA aqueous 

556

Kinetics of carbon dioxide absorption into aqueous solutions of 1, 5, 8, 12- tetraazadodecane (APEDA) 

solution. The originality of the present work consists 

of two aspects: the solvent, and the apparatus. The 

solvent was a 1.45 M APEDA aqueous solution, a 

polyamine which has not yet been used for the CO 2 

absorption. The apparatus is described in the next 

section. 


2.1. Experimental apparatus 

The apparatus (Fig. 2) is a Lewis type absorber 

with a constant gas-liquid interface area of (15.34 ± 

0.05) x 10 -4 m 2 . The total volume available for gas 

and liquid phases is (0.3504±0.0005) 10 -4 m 3 . The 

temperature is kept constant within 0.05 K by 

circulating a thermostatic fluid through the double 

glass jacket. The liquid phase is agitated by a six 

bladed Rushton turbine (4.25x 10 -2 m diameter). The 

gas phase is agitated by 4x10 -2 m diameter propeller. 

Both agitators are driven magnetically by a variable 

speed motor. The turbine speed is checked with a 

stroboscope. 

The kinetics of gas absorption is measured by 

recording the absolute pressure drop through a 

SEDEME pressure transducer, working in the range 

(0 to 200) x10 3 Pa. A microcomputer equipped with a 

data acquisition card is used to convert the pressure 

transducer signal directly into pressure P units, using 

calibration constant previously determined, and 

records it as function of time. 

The amounts of water and amines are 

determined by differential weightings to within ±10 -2 

g. This uncertainty on weightings leads to 

uncertainties in concentrations of less then ± 0.05%. 

The flask containing the degassed APEDA 

aqueous solution is connected to the absorption cell 

by means of a needle introduced through the septum 

situated at the bottom of the cell. Weighing the flask 

with the tube and the needle before and after transfer 

allows the determination of the exact mass of solvent 

transferred into the cell. 

Once the amine aqueous solution is loaded and 

the temperature equilibrated, the inert gas pressure P i 

corresponding mainly to the solvent vapor pressure 

plus eventual residual inert gases is measured. The 

pure CO 2 is introduced over a very short time (about 

2 s) in the upper part of the cell, the resulting pressure 

P 0 is between (100-200) x10 3 Pa. Then stirring is 

started and the pressure drop resulting from 

absorption is recorded. 

2.3. Materials 

The main materials involved have been: water, 

carbon dioxide, 1,5,8,12-tetraazadodecane (APEDA). 

Ordinary twice-distilled water was used. Carbon 

dioxide, purchased from Air Liquid, of 99.995% 

purity, was used as received. APEDA from Alfa 

Aesar (Store Road, Heysham) material certified 96.5 

% was used as received. Table 1 lists the main 

properties of the amine used. 

Solution densities were measured with an 

Anton Paar (Graz, Austria) vibrating tube densimeter, 

model DMA 512. 

Table 1. The main properties of the APEDA 

(http://www.chemicalland21.com/arokorhi/specialtychem/fi 

nechem) 

Fig.2. Flow diagram of the absorption equipment 

2.2. Experimental procedure 

Water and APEDA are degassed 

independently and aqueous solutions are prepared 

under a vacuum. 

Property 

Value 

Physical state 

Pale yellow liquid 

CAS N0. 10563-26-5 

Structural 

CH2 −NH −CH2 −CH2 −CH2 −NH2 

formula 

I 

CH2 −NH −CH2 −CH2 −CH2 −NH2 

Name 

1,5,8,12- Tetraazadodecane 

Synonyms N-[2—(3- Aminopropylamino)ethyl]-1, 3- 

Propanediamine; 

N, N’-Bis(3 – aminopropyl) diaminoethane; 

N, N’- Bis(3- aminopropyl)ethylenediamine; 

N, N’- Diaminopropylethylenediamine; 

N, N’- 1, 2- ethanediylbis- 1, 3- 

Propanediamnine 

Molecular 

174.29 

weight, kg/kmol 

Chemical formula C 8 H 22 N 4 

Boiling point, o C 170 

Melting point, o C - 1.5 

Density, at 293 

952 

K, kg/m 3 

Flash point, o C 142 

Stability 

Stable under ordinary conditions 

Solubility in 

Miscible 

water 

Refractive index, 

1.4910 

at 293 K 

557


3. Results and discussion 

The primary experimental results have been 

interpreted on the basis of the gas- liquid chemical 

process theory (Siminiceanu, 2004). The rate of the 

chemical absorption of CO 2 ( = i)is of the form (4): 

- dn i / A dt = E k o L C e i , mol/ m 2 s, (4) 

The gas phase is assumed ideal (Pi V g = n i 

RT), CO 2 is completely consumed by the reaction in 

the liquid film, and the CO 2 concentration at the 

interface is replaced by the Henry law ( C e i = P i e / H i ). 

The partial pressure of CO 2 is obtained by subtraction 

of vapor pressure of the solution ( P v ) from the total 

measured pressure (P T ) : P i = P T – P v . By integrating 

(4) under these assumptions, the equation (5) is 

derived: 

ln (P T - P v ) t / (P T – P v ) to = - β (t- t o ) (5) 

where: 

β= E k L 0 ART/ V g H i (6) 

The enhancement factor E can be calculated 

for each experiment, using the Eq. (6). 

In order to compare our results with those for 

other solutions at the same temperature, the overall 

rate constant (k ov ) of the pseudo- first order reaction 

has been calculated for the fast reaction regime (E = 

Ha > 3): 

k ov = (k L 0 E ) 2 / D i (7) 

The mass transfer coefficient k L 0 is calculated 

with the Eq. (8) which was established, using the N 2 O 

analogy, for the absorber also applied in these new 

kinetic experiments (Amararrene and Bouallou, 

2004): 

calculated with the Eqs (9) and (10), respectively 

(Versteeg and van Swaaij, 1988): 

H 0 i = 2.8249x10 6 exp (-2044/T) (9) 

D o i = 2.35x10 -6 exp (-2119/T) (10) 

The presence of the amine in water decreases 

the gas solubility (“salting out effect”). Taking into 

account the influence of the ionic strength of the 

solution on the solubility (Siminiceanu, 2004) with an 

equation of Sechenow type, the H i for the solution of 

1.45 M APEDA was evaluated with (11): 

H i = 1.113 xH 0 i (11) 

The diffusivity of CO 2 in the APEDA aqueous 

solution was evaluated with Eq. (12), tested in a 

previous work (Siminiceanu et al., 2006): 

D i = (D o i/ 2.43) ( µ L / µ W ) 0.2 (12) 

The ratio µ L /µ W has been correlated for the 

APEDA solutions on the basis of experimental data 

published in a previous paper (Tataru-Farmus et al., 

2007). 

The results from the Table 3 (first row, for the 

same loading) can be compared to those obtained for 

the absorption of CO 2 in a solution of AMP (1.5 M) 

with different doses of PZ as activator, in a wetted 

wall column absorber at the same temperature and a 

loading a= 0.288- 0.031 (Sun et al., 2005). 

The value obtained in this work with APEDA 

(k ov =17255.51 s -1 ) is higher than k ov for AMP with 

0.1 and 0.2 M piperazine, and inferior to that for 

larger doses of PZ. It must be noted that he solution 

AMP- PZ- H 2 O gives the grates absorption rate 

among the new systems studied in the literature in the 

last decades. 

Sh = 0.352 Re 0.618 Sc 0.434 (8) 

Where the dimensionless Sherwood (Sh), 

Reynolds (Re) and Schmidt (Sc) numbers have been 

defined as follows: 

Sh= k L 0 D c / D i 

Re= ρ L N d st / µ L 

ln k ov 

12.00 

11.50 

11.00 

10.50 

10.00 

9.50 

9.00 

8.50 

a=0.05-0.10 

Sc= µ L / ρ L D i 

E being calculated with Eq. (6), using the 

experimental values of β from the Tables 2, 3, and 4. 

The Henry constant (H o i) and the diffusion 

coefficient (D o i) for the system CO 2 - H 2 O have been 

8.00 

3.00 3.10 3.20 3.30 3.40 

1000/T, K -1 

Fig. 3. The Arrhenius plot at low loading (a= 0.05- 0.10 

mol CO2/ mol APEDA) 

558


Table 2. Experimental and calculated data for the absorption of CO 2 in APEDA (1.45 M) aqueous solution at 298 K. 

a, 

molCO2/mol 

APEDA 

β 

H i , 

D 

Pa.m3/mol CO , m²/s 0 

2 

k , m/s E=Ha kov , s -1 

l 

0.012 0.028 2965.85 2.00E-09 1.96E-05 206.04 8 490.91 

0.070 0.026 2965.85 2.00E-09 1.96E-05 191.32 7 030.98 

0.180 0.025 2965.85 2.00E-09 1.96E-05 183.96 6 500.34 

0.295 0.023 2965.85 2.00E-09 1.96E-05 169.24 5 501.79 

0.382 0.022 2965.85 2.00E-09 1.96E-05 161.88 5 033.48 

0.484 0.021 2965.85 2.00E-09 1.96E-05 154.52 4 586.39 

Table 3. Experimental and calculated data for the absorption of CO 2 in APEDA (1.45 M) aqueous solution at 313 K 

a, 

H 

molCO2/mol β 

i , D , m²/s 

CO 

Pa.m3/mol 2 

APEDA 

0 

k , m/s l 

E=Ha kov , s -1 

0.031 0.040 4110.08 2.10E-09 2.16E-05 278.69 17 255.51 

0.087 0.036 4110.08 2.10E-09 2.16E-05 250.82 13 125.00 

0.208 0.035 4110.08 2.10E-09 2.16E-05 243.85 12 487.19 

0.305 0.034 4110.08 2.10E-09 2.16E-05 236.88 11 783.55 

0.409 0.030 4110.08 2.10E-09 2.16E-05 209.01 9 173.88 

0.508 0.027 4110.08 2.10E-09 2.16E-05 188.11 7 862.10 

Table 4. Experimental and calculated data for the absorption of CO 2 in APEDA (1.45 M) aqueous solution at 333 K 

a, 

H 

molCO2/mol 

i , D , m²/s 

CO 

Pa.m3/mol 2 

APEDA 

0 

k , m/s l 

E=Ha kov , s -1 

0.047 0.041 6098.76 2.23E-09 2.49E-05 445.95 55 292.49 

0.109 0.041 6098.76 2.23E-09 2.49E-05 445.95 55 292.49 

0.222 0.040 6098.76 2.23E-09 2.49E-05 435.07 52 627.42 

0.330 0.033 6098.76 2.23E-09 2.49E-05 358.93 35 818.99 

0.430 0.029 6098.76 2.23E-09 2.49E-05 315.43 27 663.03 

0.518 0.026 6098.76 2.23E-09 2.49E-05 282.79 22 235.57 

Table 5.The results for the absorption of CO 2 in 1.5 M solutions of AMP activated with PZ at 313 K (Sun et al., 2005) 

C o PZ, mol/L ax 10 2 , k o Lx 10 5 , 

mol/mol m/s 

D i x10 9 , 

m 2 /s 

H i , 

Pa m 3 /mol 

N A x 10 6 , 

kmol/m 2 s 

k ov , 

s -1 

0.1 3.11 3.97 1.72 4 144 3.46 7 530 

0.2 2.88 4.05 1.66 4 047 3.88 13 857 

0.3 3.10 3.68 1.57 4 095 4.31 20 572 

0.4 3.16 3.64 1.42 4 070 4.52 27 819 

ln kov 

12.00 

11.50 

11.00 

10.50 

10.00 

9.50 

9.00 

8.50 

8.00 

a=0.40-0.50 

3.00 3.10 3.20 3.30 3.40 

1000/T, K -1 

ln k ov 

11.50 

11.00 

10.50 

10.00 

9.50 a=0.00-0.05 

a=0.05-0.10 

a=0.10-0.20 

9.00 a=0.20-0.30 

a=0.30-0.40 

a=0.40-0.50 

8.50 

3.00 3.10 3.20 3.30 

1000/T, K -1 

Fig. 4. The Arrhenius plot at high loading (a= 0.40- 0.50 

mol CO2/ mol APEDA) 

Fig. 5. The Arrhenius plots for all experimental loadings 

559


Table 6. The kinetic parameters derived from the Arrhenius 

plot 

a 

Ea A= 

0 

ln k 

molCO 2 /mol 

ov B=Ea/R, 

APEDA cal/mol kJ/mol 

K 

0.00-0.05 10 553.89 44.11 26.496 5 311.02 

0.05-0.10 10 616.18 44.37 26.877 5 342.72 

0.10-0.20 10 782.52 45.06 27.272 5 426.27 

0.20-0.30 10.552.85 44.11 25.931 5 310.52 

0.30-0.40 9 599.42 40.12 24.238 4 830.90 

0.40-0.50 8 890.80 37.16 24.671 4 474.08 


The aqueous monoethanolamine (MEA) is 

now considered the most convenient among the 

available absorption technologies for removing 

carbon dioxide from flue gas streams. Nevertheless, 

this process has a number of drawbacks, pointed out 

in the introductory section of this paper, which make 

it rather expensive. Its application to fossil fuel power 

plants could increase the cost of electricity production 

by up to 82.8 % (Abu- Zahra et al., 2007b). This 

paper presents some results of a study aiming to 

develop a new solvent in order to improve the 

efficiency of the CO 2 removal from flue gas. 

The absorption of CO 2 into an aqueous 

solution with 1.45 mol/L 1,5,8,12- tetraazadodecane 

(APEDA) polyamine has been studied at three 

temperature (298, 313, 333 K) in a Lewis type 

absorber with a constant gas- liquid interface area of 

(15.34 ± 0.05) x 10 -4 m 2 . The experimental results 

have been interpreted using the equations derived 

from the two film model with the assumption that the 

absorption occurred in the fast pseudo- first- order 

kinetic regime. The results confirmed the validity of 

this assumption for the experimental conditions: the 

enhancement factor was always greater than 3. 

According to the results, the rate constat 

(kov) increased with the temperature, and decreased 

with the carbonation degree/ loading (a= mol 

CO 2 /mol amine). For each loading the Arrhenius 

equation was satisfactory verified. The activation 

energy (41.9 kJ/mol) indicated that the process 

proceeded close to the boundary between the kinetic 

and the mass transfer regime. The optimal values of 

the constants A and B from the Arrhenius equation 

(lnk = A- B/T) were derived by linear regression, for 

each loading. These will be useful for the industrial 

absorption column modeling and simulation. 

The rate constant derived from experiments 

is of the same order of magnitude as that for the 

absorption into 2- amino- 2- methyl- 1- propanol 

(AMP) activated with piperazine (PZ) which was 

found to be the most advanced system among the 

published data up to now( Sun et al., 2005). At T= 

313 K and a< 0.05, for instance, k ov = 17 255 s -1 for 

APEDA, compared to 20 572 s -1 for 1.5M of AMP 

with 0.3M of PZ under the same conditions. 

The preliminary results presented in this paper 

show that, from the kinetic point of view, the 

absorption of CO 2 from flue gas into APEDA solution 

is a promising process for practical application .Other 

potential advantages of APEDA compared to MEA : 

higher loadings( smaller solution flow rates), less 

energy required for regeneration, lower degradability 

and corrosiveness. It is still to prove the unavoidable 

existence of some drawbacks, such as, volatility, 

toxicity and cost. 

Notation 

A, area of the gas- liquid interface, m 2 ; 

a, moles of gas absorbed per mole of amine (loading), 

mol/mol; 

C i , molar concentration, kmol/m 3 ; 

D o i , diffusion coefficient of i in water, m 2 /s; 

D i , diffusion coefficient of i in solution, m 2 /s; 

D c , absorption cell internal diameter, m; 

d st , stirrer diameter, m; 

E, enhancement factor of absorption by the chemical 

reaction; 

H i , Henry constant for the absorption of CO 2 in the APEDA 

solution, Pa. m 3 / mol; 

H i o , Henry constant for the absorption of CO 2 in water, Pa. 

m 3 / mol; 

Ha, Hatta number; 

k L 0 , liquid side mass transfer (without chemical reaction) 

coefficient, m/s; 

k L= E k L 

0 

, liquid side mass transfer with chemical reaction 

coefficient, m/s; 

k ov , pseudo- first order reaction rate constant, s -1 ; 

N, rotation rate, s -1 ; 

n i , number of moles of i; 

P, total pressure, Pa; 

P i , partial pressure of the gas i, Pa; 

P v , vapor pressure of the solution, bar; 

R, gas constant (8.314 Pa m 3 / mol); 

Re, Reynolds number; 

Sc, Schmidt number; 

Sh, Sherwood number; 

T, temperature, K; 

t, time, s; 

V g , gas phase volume, m 3 ; 

β, the slope in the equation (3), s -1 ; 

ρ L, liquid density, kg/ m 3 ; 

µ L, liquid viscosity, Pa s; 

µ, viscosity of water, Pa s. 

References 

Abu-Zahra M.R.M., Schneiders L.H.J., Niederer J.P.M., 

Feron P.H.M., Geert F., (2007), CO 2 capture from 

power plants. Part I. A parametric study of the 

technical performance based on monoethanolamine, 

International Journal of Greenhouse Gas Control, 1, 

37- 46. 

Abu-Zahra M.R.M., Niederer J.P.M., Feron P.H.M., 

Versteeg G.F., (2007), CO 2 capture from power 

plants. Part II. A parametric study of the economic 

performance based on monoethanolamine, 

International Journal of Greenhouse Gas Control, 

1,136- 142. 

Amararrene F., Bouallou Ch., (2004), Kinetics of carbonyl 

sulfide absorption with aqueous solutions of 

560


diethanolamine and methyldiethanolamine, Ind. Eng. 

Chem. Res., 43, 6136-6141. 

Bello A., Idem R.O., (2005), Pathways for the formation of 

products of the oxidative degradation of CO 2 loaded 

concentrated aqueous MEA solutions during CO 2 

absorption from flue gases, Ind. Eng. Chem. Res., 44, 

945- 969. 

Dallos A., Altsach T., Kotsis L., (2001), Enthalpies of 

absorption and solubility of carbon dioxide in 

aqueous polyamine solutions, J. Thermal Analaysis 

and Calorimetry, 65, 419- 423. 

Hilliard M.D., (2005), Dissertation Proposal, University of 

Texas at Austin, 1-27. 

Kohl A.L., Nielsen R., (1997), Gas Purification, 5th ed., 

Gulf Publ.Corp., Texas, 250-281. 

http://www.chemicalland21.com/arokorhi/specialtychem/fi 

nechem/1,5,8,12-TETRAAZADODECANE. 

Siminiceanu I., (2004), Procese chimice gaz- lichid, Editura 

Tehnopres, Iasi, 180- 288. 

Siminiceanu I., Tataru-Farmus R.E., Amann, J.-M., (2006), 

Kinetics of carbon dioxide bsorption into aqueous 

solutions of etilenediamine, Buletinul Inst. Polit. 

Iaasi, Tom 52, 1-2, Chim. Ing. Chim., 45- 50. 

Strazisar B.R., Anderson R.R., White C.M., (2003), 

Degradation pathways for MEA in a CO 2 capture 

facility, Energy Fuels, 17, 1034- 1039. 

Sun W.-C., Yong C.-B., Li M.-H., (2005), Kinetics of the 

absorption of carbon dioxide into mixed aqueous 

solutions of 2- amino- 2- methyl- 1- propanol and 

piperazine, Chem. Eng. Sci., 60, 503- 516. 

Tanthapanichakoon W., Veawab A., McGarvey B., (2006), 

Electrochemical investigation of the effect of heat 

stable salts on corrosion in CO 2 capture plants using 

aqueous solution of MEA, Ind. Eng. Chem. Res., 45, 

2586- 2593. 

Tataru- Farmus R.E., Siminiceanu I.,Bouallou Ch., (2007), 

Carbon dioxide absorption into new formulated 

amine solutions (I), Chemical Engineering 

Transactions, 12, 175- 181. 

Thitakamol B., Veawab A., Aroonwilas A., 

(2007),Environmental impacts of absorption- based 

CO 2 capture unit for post- combustion treatment of 

flue gas from coal fired power plant, International 

Journal of Greenhouse Gas Control, 1, 318- 342. 

Versteeg G.V., van Swaaij W.P.M., (1988), Solubility and 

diffusivity of acid gases (CO 2 , N 2 O) in aqueous 

alkanolamine solutions, J. Che. Eng. Data, 33, 29- 34. 

561

562




______________________________________________________________________________________________ 

URBAN TRAFFIC POLLUTION REDUCTION USING AN INTELLIGENT 

VIDEO SEMAPHORING SYSTEM 

Codrin Donciu ∗ , Marinel Temneanu, Marius Brînzilă 

“Gh. Asachi” Technical University of Iasi, 53 Mangeron Blvd., 700050, Iasi, Romania 

Abstract 

The present paper suggests making an intelligent video system of command over crossroads with traffic lights, its main goal being 

diminishing road congestion, a better traffic speed of vehicles, diminishing the environment pollution and improvement of 

negative effects that vehicle concentration has over the physical and psychological state of the population. 

Key words: vision, image processing, segmentation 


On a global level, after the Bureau of 

Transportation Statistics, Ward's, Motor Vehicle 

Facts & Figures 2006, total production of automobiles 

(both for passengers and trade) gas grown from 

15.200 thousands automobiles in 1961, reaching 

values of 33.401 thousands in 1971, 37.136 thousands 

in 1981, 47.283 thousands in 1991, 57.528 thousands 

in 2000 and finally 65.750 thousands auto vehicles in 

2005 as shown in Fig. 1. It is notable that the entire 

auto-park of the rolling vehicles is obtained by 

summing the production for a number of years equal 

to the average of vehicles circulation, a specific 

average for each country (Chen et al., 2000). 

Fig. 1. Global vehicle production 

The exponential growth of the last decade of 

the rolling vehicle number, on both national and 

global level, is, among other factors, an important 

cause of chemo-physical pollution level growth, of 

augmentation of global warming, of phonic pollution 

and of stress risk factor enlargement (Dementhon et 

al., 2000). Further more, as noticed in Fig. 2, the 

waiting of the cars with the engine on, or the rolling 

with speeds below 12km/h induces a fast growth of 

CO, organic volatile substances and azotes oxides 

emissions (Fan et al., 2000). 

In this context, this project suggests making an 

intelligent command video system of the trafficlighted 

crossroads, its main goal being to diminish of 

traffic congestions, to improve vehicle speed, to 

reduce environment pollution and to improve 

negative effects of traffic congestion over the physic 

and psychic state of the population (Ferman et al., 

1997). On international level, automatic advanced 

command systems of crossroad traffic-lightening 

have a bigger spread. They are classified according to 

the physical area of sensible elements mounting 

(sensors and traitors) and can be placed: at the traffic 

rolling level, in the pavement or along the traffic 

lanes. Detection throughout pavement mounted 

sensors is the most commonly used technology in the 

present (Haritaoglu et al., 2000). 

∗ Author to whom all correspondence should be addressed: cdonciu@ee.tuiuasi.ro


2. System architecture 

Fig. 2. CO, VOC, NOX variation depending of vehicle 

speed 

At the traffic rolling level there are the 

following constructive alternatives: 

• loop plates, similar to conventional inductive 

loops, meaning that they generate an 

electromagnetic field, troubled by a vehicle’s 

passing-by; 

• pressure plates, which upon the wheels passing-by 

discharge an electric current. This device is 

limited to the axles passing-by, not vehicles; 

• magnetometer, which measure changes in the 

Earth’s magnetic field upon a vehicle’s passingby. 

At the pavement level the following 

constructive alternatives are used: 

• magnetic inductive loops are the type of 

detector the most commonly used. They 

generate an electromagnetic field that is 

troubled upon the vehicle passing-by, and 

that detects the vehicle’s presence in this 

manner. The size of a loop is generally 

1x1,5m; 

• magnetic probes measure changes in Earth’s 

magnetic field, in order to detect the 

vehicle’s passing-by over them. 

• sensitive cables. Upon the vehicle’s passingby 

over a sensitive cable, the tires produce 

compression of the piezoelectric cable, 

which generates instantly an electric signal. 

Hey cannot however measure some traffic 

parameters, and are limited to detection of 

the axle. 

Along the traffic ways, there are video 

cameras installed, set into crossroads with the main 

target of indicating any violation of the red signal in 

traffic lights (Krumm et al., 2000). They use a trigger 

for the beginning of the record which comes from a 

sensor set into the pavement. If the red signal appears 

at the traffic lights, and the pavement sensor detects a 

vehicle moving above it, the record is started 

(Puzicha et al., 1999). The above presented systems 

are used in low traffic crossroads, being able to 

interpret information only from the near proximity of 

the sensors, but unable to estimate the number of 

vehicles waiting in line on a traffic lane (Sista et al., 

2000). 

This project approaches the build of an 

intelligent command video system for trafficlightening 

crossroads, its main goal being to diminish 

of traffic congestions, to improve vehicle speed, to 

reduce environment pollution and to improve 

negative effects of traffic congestion over the physic 

and psychic state of the population. It also brings up 

the possibility of extending this system to a macrotype 

that can also offer the benefit of a ‘green wave’ 

inter-synchronizing. 

The architecture of the suggested system is 

made on a hardware level from three different areas: 

the video sensor’s level (video cameras), the 

computer process level and the represented execution 

level and the traffic-lights that exist in the crossroad. 

(Fig. 3). 

Webcams have the role to import in real time 

images of the road traffic and can be placed 

depending on the urban configuration of the crossroad 

(if there are/are not trees/buildings higher than 12 m, 

slopes leaned more than 5 %) in two alternatives: AC 

– altitude camera with an overview of the crossroad, 

or CS – camera system set on the directions of the 

traffic lanes. In this last choice, one of the cameras 

must have an optic view transverse to the center of 

the crossroad, by mounting it in a diametric opposite 

point compared to the crossroad and monitor artery 

conjunction. 

Fig. 3. System architecture 

The process computer represents the hardware 

support of the algorithms and routines destined to 

564

Urban traffic pollution reduction 

image processing and fuzzy control. The data 

transmission between the process computer, the video 

cameras and the execution elements is made by radio 

or cable, depending on the crossroad configuration. 

The software architecture of this system is 

made out of the main routine and a number of 

secondary routines of image processing and of the 

Fuzzy command. The fundamental routine has, as 

target, the determination of the vehicle number 

waiting in line on a traffic lane. For this, as you can 

notice in Fig. 3, the main IP image, that comes from 

the altitude camera AC or the one obtained by 

reconstructing the image (RIT) from the CS camera 

system, is submitted to a pre-processing process for 

removing the video sounds, followed by a numeric 

differentiation process from the background image IF 

and by applying a ‘high-pass’ filter to emphasize 

shapes. The processing operation is done by 

segmentation, obtaining the IS image. By segmenting 

we get to make partitions of the numeric image into 

sub-sets, by attributing individual pixels to these subsets 

(also named classes), resulting into distinctive 

objects from the scene, through the bridge method. 

And so, because of the significant differences 

between the grey levels of the object’s pixels and the 

background’s, the segmenting criteria are the grey 

level value. The pixel corresponding to the coordinate 

point (i,j) is considered to be an object-pixel if it’s 

value (i, j) is higher than a bridge value. 

Obtaining good results by this method depends 

of the way the bridge is chosen, which can be a value 

for a certain image that is given or a slim function 

that depends on the pixel’s positioning. The last stage 

of the fundamental routine is the N sequence of 

estimating the number of vehicles waiting in line and 

the build of the E (e1, e2, ……. en) vector, who’s 

elements are the numbers of vehicles standing in line 

on the road artery, and the index represents the 

number allocated to the road arteries (or to the traffic 

lanes, if on from way there are several directions that 

can be followed). 

The secondary routines of image processing 

gather the event memory EM routine, the algorithm 

for unfriendly weather conditions detection DCMN 

and the emergency situations detection algorithm 

SDU. 

The event memory routine uses a circular 

recording buffer with a stocking capacity of 48 h and 

its role is to provide witness video digital recordings 

for road-event like situations (road accident of 

robbery from vehicles in crossroads). The routine also 

fulfils the “running the red light” function. In the case 

of traffic violation by crossing over the red signal at 

the traffic-lighted crossroads a digital trigger is 

activated and an image of the vehicle is stored in a 

special location. The bad weather condition detection 

algorithm DCMN has as a goal establishing the 

visibility conditions in a crossroad and the road 

adherence by identification night/day, the existence of 

rain/snow weather phenomenon’s and deposition 

level on the road. The going-out value of this 

algorithm through the BI delaying block applies 

corrections depending on weather conditions and the 

times provided by BCF. The DSU - emergency 

situations detection algorithm’s goal is to establish 

the approach to the crossroad of a light-signaled 

vehicle – ambulance, police car, firemen’s cars or 

official cars - followed by priority on the identified 

lane given by the Fuzzy BCF command block. The 

Fuzzy BCF command block is the central part of the 

whole traffic-lightening system and has the role to 

establish, upon the data send by the fundamental and 

secondary routines, the command times of the trafficlights. 

On an overview look, by its architecture, this 

project represents a high novelty solution with also 

high complexity in crossroads traffic-lightening, 

taking into consideration that such a configuration is 

not yet implemented. Development of the algorithms 

necessary to this crossroads traffic-lightening 

intelligent video system requires a interdisciplinary 

and complex approach of this matter, by putting 

together knowledge from domains such as: numeric 

view of the signals, Fuzzy artificial intelligence and 

data transmission. 

In particular, the project is distinctive by the 

following novelty aspects: 

• the secondary routines for image processing (the 

memory routine EM, the bad weather condition 

detection algorithm DCMN and the emergency 

situations detection algorithm SDU) give to this 

system a high level in command decisions making 

and furthermore is gives adaptability to trafficlightening 

depending on weather conditions and 

emergency situations; 

• the development of a new FFT image processing 

algorithm, with a processing speed higher than the 

classical alternative and with frequency, 

amplitude and phase errors substantially reduced, 

necessary to the co-existence of the two different 

processing types: the fundamental routine and 

detection algorithm of the bad weather condition 

detection by using an overview level processing, 

while the emergency situations detection 

algorithm uses an identification processing on a 

detail level; 

• the making of an adjustable traffic-lightening to 

the necessities of the traffic type and conditions. 


Development of proposed system has a large 

impact under economical, health and environment 

aspect. Under economical aspect, taking into 

consideration the overwhelming growth of the vehicle 

number in the past decades, the existence of an 

intelligent traffic-lighted crossroad system has as an 

immediate result a better traffic flow efficiency, this 

being emphasized under reduction of the medium 

time travel on a certain itinerary. On another side, the 

fuel burnings due to repeated stops/slowing-downs 

and accelerations is reduced, with significant values 

on medium and long time length. 

565


Health impact. The pollution substances 

emissions, such as nitrogen oxides, hydrocarbons, 

CO, powders causes or contributes to a series of 

health problems. Within the impact over population 

health attributed to road traffic we can assume a 

higher incidence of cancers and lung and cardiac 

diseases. The technological improvements, which 

reduced the emission level, have been compensated 

by a traffic growth, and so emissions are still 

growing. Auto vehicles, and especially cars, are the 

main source of air pollution in urban areas on 

European level. Approximately 65% of the European 

Union’s population is submitted to unacceptably high 

noise levels – mainly produces by urban traffic. 

Although noise affects individuals in different 

manners, it causes both discomfort and health 

problems. Among the effects over the physiological 

and psychical state there are: a higher heart rate (with 

associated higher risk of cardio-vascular diseases), 

physiological trouble and higher daily stress level, 

sleep disorders, cognitive troubles, comprehension 

and focusing troubles for the children, and at very 

high noise levels, hearing problems. 

Implementing a smart system traffic-lightening 

level has as a direct result a higher life level quality 

for the people living in areas next to traffic 

congestions, both through diminishing noise level 

produced by the engines and through diminishing 

concentrations of atmospheric pollutant’s emissions. 

Furthermore, there are lower exposure levels for 

bicyclists, pedestrians and other categories of 

unprotected persons, such as police crews stationary 

in crossroads or workers that are set next to high 

traffic congestion crossroads, etc. 

Under environmental impact, pressures of the 

urban traffic upon environment are expressed by: 

• street noise and vibrations; 

• air pollution with particles, sediment powders, 

NOx; 

• SOx, hydrocarbons, Pb; 

• air emissions of gases that have warming and acid 

effects, therefore leading to global warming. 

Congestions and traffic delays raise the fuel 

burnings and, obviously, the level of physicalchemical 

pollution of the air. Latest studies estimate 

that, in the European Union, the transportation sector 

is responsible for 28% of the total CO2 emission, the 

main gas in global warming. Of this value, 84%, so 

the biggest part comes from road vehicles. 

While industrial emissions are lowering their 

values, in agreement with EU ratification through 

Tokyo agreement, transportation emissions are 

growing continuously. It is estimated that in 2010, 

emission level will be 40% higher than the one in 

1990, despite the fact that EU target for this period is 

to diminish by 8 % gas emissions with global 

warming effect. 

Transportation sector is responsible for 63% of 

NOx emissions, 47% of organic volatile compounds 

emissions, such as benzene, 10-25% of the powder 

emissions and 6,5% of the SO 2 emissions in countryside 

areas, those values increasing in the urban areas. 

Bu achieving this project’s objectives, the 

level of physical-chemical pollution in the interested 

areas will lower significantly, contributing in this 

manner in a specific way to the improvement of 

combat against global warming. Just as important, 

due to traffic continuous flow in crossroads, the level 

of phonic pollution will diminish also. At this point, 

the maximum allowed decibels level is 50, but the 

value reaches 80, or even 100 in the big crossroads, 

extremely troubling for residents of near-by areas. 

From electromagnetic pollution point of view, there is 

a lowering in the intermittent wide range 

perturbations, generated by the vehicle’s lightening 

installations and associated with intense traffic and 

crossroads congestions. These perturbations level in 

the GHz domain depends on the distance and number 

of vehicles on a given area, being able to cause some 

electromagnetic compatibility problems. 

References 

Chen C., Shyu L., Zhang C., Kashyap R., (2000), Object 

Tracking and Augmented Transition Network for 

Video Indexing and Modeling, 12 th IEEE Int. 

Conference on Tools with Artificial Intelligence, 1, 

Vancouver, May, 428. 

DeMenthon D., Stuckelberg M., Doermann D., (2000), 

Image Distance using Hidden Markov Models, 

International Conference Pattern Recognition: Image, 

Speech and Signal Processing, 1, Barcelona, Sept., 

147. 

Fan L., Sung K., (2000), Model-Based Varying Pose Face 

Detection and Facial Feature Registration in Video 

Images, 8th ACM Int. Conference on Multimedia, 1, 

Los Angeles, Oct., 295 

Ferman M., Guensel B., Tekalp, M., (1997), Object-based 

Indexing of MPEG-4 Compressed Video, Proc. of 

SPIE: Visual Communications and Image Processing, 

1, San Jose, Feb., 953. 

Haritaoglu I., Harwood D., Davis, L., (2000), A Fast 

Background Scene Modeling and Maintenance for 

Outdoor Surveillance, 15th IEEE Int. Conference on 

Pattern Recognition: Applications, Robotics Systems 

and Architectures, 1, Barcelona, Sept., 179. 

Krumm J., Harris S., Meyers B., Brumitt B., Hale M., 

Shafer S., (2000), Multi-Camera Multi- Person 

Tracking for EasyLiving, 3rd IEEE Int. Workshop on 

Visual Surveillance, 1, Dublin, July, 3. 

Puzicha J., Hofmann T., Buhmann M., (1999), Histogram 

Clustering for Unsupervised Image Segmentation, 

IEEE Computer Society Conference Computer Vision 

and Pattern Recognition, 1, Fort Collins, June, 602. 

Sista S., Kashyap L., (2000), Unsupervised Video 

Segmentation and Object Tracking, Computers in 

Industry, 42, 127-146. 

566




______________________________________________________________________________________________ 

STUDY OF INCREASING SOIL FERTILITY INTO A SITE 

WITH HIGH ELECTRIC FIELD AROUND 

USING POLYMERIC CONDITIONING AGENT 

Ioan Ivanov Dospinescu , Carmen Zaharia, Matei Macoveanu ∗ , 

“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering, Department of Environmental Engineering 

and Management, 71A D.Mangeron Bd., 700050 - Iasi, Romania 

Abstract 

This paper discusses the applications of synthetic PONILIT GT-2 anionic polyelectrolyte as soil conditioning agent into a site 

with high electric field around. All experimental data conclude that the use of a polymeric conditioning agent was increased the 

soil ability to support vegetation expressed as germination degree for some grass species (e.g., Raigras aristat). The performed 

values for germination degree increase from 3.05 % to 12.20 % when was added fertilized soil, and respectively, 38.98-73.17 % 

when is added polymeric agent. Moreover, the experimental data concludes that the use of lower polyelectrolyte concentration is 

indicated (e.g., < 5 mL polyelectrolyte solution of 0.5 % per 1 Kg soil). The negative environmental impact of high electric 

tension into the investigated site can be attenuated if is used a soil conditioning agent as Ponilit GT-2 anionic polyelectrolyte. 

Key words: PONILIT GT-2 anionic polyelectrolyte, soil conditioning agent, germination degree, soil fertility, Raigras aristat 


It had been widely recognised by 

government that soil protection is important within 

the concept of sustainable development. A report 

commissioned by the Environmental Agency 

identified a bias towards indicators designed to 

monitor the quality of soil with respect to its ability to 

support all vegetation including grassland, arable 

crops and trees or other “agricultural activities" rather 

than the full range of broad soil functions (e.g., food 

and other biomass production; storing, filtering and 

transformation of minerals, organic matter, water and 

energy, and diverse chemical substances; habitat and 

gene pool; physical and cultural environment for 

mankind; source of raw materials etc.). It 

recommended the adoption of a “goods and services” 

approach whereby the ability of soils to perform the 

wide range of functions society needs is implemented 

and the definition of “soil quality” varies with these 

functions (Tzilivakis et al., 2005). 

The heterogeneity of soils, the wide range of 

functions and services they perform and the variety 

and combination of pressures placed upon them all 

require much consideration. Soils are poorly 

understood when compared with other environmental 

media. They vary enormously in their chemical and 

physical constitution and, as a consequence, their 

ability to perform functions (Zaharia et al., 2006; 

Surpateanu and Zaharia, 2002). 

Different activities place different pressures on 

the soil and cause different impacts. Across the 

Europe, the threats to soil include erosion, decreasing 

levels of organic matter, local and diffuse 

contamination, sealing, compaction, declining biodiversity 

and salinisation (European Commission, 

2002). Recently, it had been investigated the high 

electric field impact on environment but especially on 

soil with respect to its ability to support vegetation. A 

negative impact of high electric field on “soil quality” 

as vegetation support was reported into a Moldavian 

site (Zaharia et al., 2006). This negative impact can 

be reduced if are used soil conditioning agents. 

This paper presents the experimental results of 

soil quality as vegetation support performed by using 

of a polymeric product (e.g., Ponilit GT-2 anionic 

∗ Author to whom all correspondence should be addressed: mmac@ch.tuiasi.ro

Ivanov Dospinescu et al./Environmental Engineering and Management Journal 6 (2007), 6, 567-572 

polyelectrolyte) as soil conditioning agent into a site 

with high electric field around. 


2.1. Site characterization and location 

The studied site is a northern Romanian area 

having a total surface of 5 ha situated no more than 5 

km from the Iasi town, named Uricani-Valea Lupului 

relays region. It is proposed an impact case study on 

soil fertility of some vegetal grass species induced by 

the high electric tension network, and improved by 

adding of soil conditioning agent such as an anionic 

polyelectrolyte. 

The investigated site is traversed by aerial 

electric tension network corresponding to values of 

40 – 70 V/m 2 into all investigation period (Antohi and 

Ivanov Dospinescu, 2003). 

2.2. Experimental procedure 

The paper is focused on soil characterization 

as vegetable support, and investigation of its ability to 

support some vegetal species of Raigras aristat into 

the investigated site presented above, with addition or 

no of fertilized soil and polymeric conditioning agent. 

The “soil quality” as vegetation support is expressed 

by its germination degrees. 

The experiments are organized into special 

vegetation vessels having rectangular shape (150x 

120x 50 mm) and perforated bottom. Into these 

vegetation vessels were introduced the studied soils 

(e.g., more than 3 cm height), and also some mixture 

between the soil from the investigated area and 

commercial fertilized soil for plants (e.g., mixtures of 

1:1, 2:1, 1:2 and 1:3 studied soil/commercial 

fertilized soil). The fertilized soil is produced by 

Matecsa Ker.Es Kert Kft Hungary and has a pH value 

of 6.6-7. 

The vegetal species, Lollium multiflorum, is a 

pretentious species that need a soil enriched in 

nitrogen, high light and water. The grass species 

grows rapidly, but can not resist more than 1-2 years 

[6]. The sowing with Lollium multiflorum was made 

according with the literature data (Canache, 1990), 

ensuring an average number of 12.500 – 15.000 

seeds/m 2 which correspond to 0.5 g seeds/vessel, 

about ca 164 seeds/vessel. After sowing into each 

vegetation vessels was introduced BIONAT fertilizer, 

commercialized by PANETONE Company, 

Timişoara, Romania containing the following 

important compounds: 74 g/L nitrogen (N), 3 g/L K 

(K 2 O), 0.2 g/L phosphor (P), 5 g/L magnesium (Mg), 

10 g/L sulphur, 1 g/L calcium (Ca) and 

microelements (1-2 g/L). 

Comparative studies were performed on soil 

treated with soil conditioning agent such as Ponilit 

GT-2 anionic polyelectrolyte, and the same growing 

condition of vegetal species (e.g., between 3 and 5 

mL polyelectrolyte solution of 0.5 % per kg soil and 

good homogenization). 

The PONILIT GT-2 anionic polyelectrolyte is 

an aqueous solution of a sodium copolymer salt based 

on maleic acid and vinyl acetate. The polyelectrolyte 

stock concentration used for this study was 0.5 % (the 

polyelectrolyte is patented by the “P.Poni” Institute of 

Macromolecular Chemistry, Iaşi) (Patent, 1981). This 

polyelectrolyte was industrially produced by the 

Chemical Enterprise of Falticeni and commercialized 

by “Chimica” Company, Bucharest having the 

following characteristics: amber colour, specific 

smell, pH of 6.5 – 8, content of active product into 

solution of 33 – 36 % (w/w), density of 1.18 – 1.21 

g/cm 3 , water soluble, viscosity at 20 ± 1°C of 1500 – 

1800 cP, average molecular mass of 2.10 5 – 3.10 6 , no 

corrosive or toxic effect. 

The germination degrees, which express the 

fertility efficiency of soil as vegetal support, are 

calculated with Eq.(1) (Surpateanu and Zaharia, 2000; 

Zaharia and Surpateanu, 2001): 

n 

f 

Germination degree (%) = ⋅100 

(1) 

n 

where: 

n i – the initial number of seeds; 

n f – the final number of vegetal species. 

A comparative study of the same soil samples 

cultivated with these vegetal species of grass was 

performed at laboratory scale set-up into almost the 

same operational condition but with no high electric 

tension around. A reference soil sample from other 

area (e.g., 5 km far from Iasi, opposite side), and a 

soil sample from 100 m far of the investigated site 

were analyzed in the same condition for comparison 

of the germination degrees. 

2.3. Analysis Methods 

The investigated soil was preliminarily 

analysed concerning the following physical and 

chemical indicators using standardized methods 

internationally approved: pH, carbon organic content, 

exchangeable calcium, total content of soluble salts, 

total phosphor, total nitrogen etc. (Surpateanu and 

Zaharia, 2002; Davidescu et al., 1981; Zaharia, 2005). 

3. Results and discussion 

All experiments were performed on soil 

samples characterized by the main physical-chemical 

indicators presented into Table 1 in order to obtain 

compact grassland. 

Into laboratory conditions, the coming up of 

vegetal species was normal, based on difference of 

soil fertility; higher for reference soil (soil sample- 

III), followed by soil samples 100 m far of the studied 

area (soil sample-II) and investigated soil (soil 

sample-I). 

i 

568

Study of increasing soil fertility into a site with high electric field around using polymeric conditioning agent 

Soil Sample 

pH 

(active pH, 

water) 

pH 

(Exchangeable 

pH, KCl 1%) 

Table 1. Soil characteristics 

C organic , 

% 

P 

(g p/kg 

soil) 

Exchangeable 

Ca 2+ 

(mg/kg soil) 

CaO 

% 

TCSS * 

mg/100 g 

Relay soil 8.78 7.72 2.15 44.8 48 2.576 400 

Soil- 100 m far 8.72 7.76 0.084 44.7 36 2.016 1115 

Mixture 7.94 7.59 3.72 - 40 2.24 300 

1:3 

Mixture 8.15 7.64 1.14 - 40 2.24 716 

1:1 

Mixture 8.29 7.66 2.54 - 36 2.016 375 

2:1 

Reference soil 7.75 7.18 0.774 15.96 48 2.688 275 

* TCSS – total content of soluble salts 

Nevertheless, the vegetal growth was 

accelerated the first six days for the reference soil, but 

during the investigated period was decreasing. For the 

commercial fertilized soil, the results are the best, 

almost total sowing of vegetal species (ca 91.20 %) 

and formation of a good grassland beginning with the 

sixth day. The daily evolution at laboratory scale setup 

of grassland into the vegetation vessels are 

presented into the next table (Table 2). 

Table 2. Evolution of vegetal species growth at laboratory 

scale set-up 

Day no/ Soil sample Soil sample Soil sample 

soil type I 

II 

III 

6 th day - 5 mm 5-10 mm 

7 th day 5-8.5 mm 10 mm 25 mm 

8 th day 10-10 mm 10-35 mm 35-50 mm 

9 th day 10-45 mm 10-50 mm 40-60 mm 

10 th day 10-60 mm 15-70 mm 50-80 mm 

11 th day 20-70 mm 20-80 mm 20-90 mm 

12 th day 20-70 mm 20-80 mm 25-100 mm 

13 th day 20-80 mm 40-110 mm 35-90 mm 

14 th day 30-80 mm 30-110 mm 35-100 mm 

15 th day 35- 85 mm 40-110 mm 40-110 mm 

16 th day 35-90 mm 45-110 mm 40-115 mm 

17 th day 35-90 mm 30-110 mm 40-130 mm 

The grassland was mowed down for improving of grass 

strength, and after the growth was decreasing 

It can be seen that after thirteen days of 

observations the vegetal species have heights higher 

than 10 cm, and that is way the grassland need to be 

mowed down. The germination degrees for these soil 

samples and vegetal species number was measured or 

calculated being presented into Table 3. 

Table 3. Efficiency of vegetal species growth (laboratory 

experiments) 

Efficiency/ Soil – I Soil – II Soil – III 

soil vessel 

Vegetal species 46 85 128 

number 

Germination 28.05 51.83 78.05 

degree, % 

I–investigated soil; II –100 m far of investigated soil; III– reference soil 

It can be considered that the germination 

degree was not so high because the sowing was 

performed on surface no deeply inside the soil. 

Although this vegetal species is sensible and was 

tested for different soils and conditions, the existence 

and growth of vegetal species was possible. 

Table 4. Efficiency of vegetal species growth (A point, 

irrigation), no treatment with polyelectrolyte 

Efficiency/ 

soil vessel 

Vegetal 

species no. 

Germination 

degree, % 

Relay (1:1) (2:1) (1:2) (1:3) 

soil 

5 20 10 20 5 

3.05 12.20 6.10 12.20 3.05 

On the investigated site were organized four 

prelevation and observation points separated each 

other by 35-45 m under and around the high electric 

tension lines between two relays in condition of daily 

irrigation (e.g., maximum 3-4 mL water), no soil 

conditioning agent (series 0), and treatment of each 

soil vessel with polyelectrolyte (series I- 3 mL Ponilit 

GT-2 solution of 0.5 % per kg soil, and series II- 5 

mL Ponilit GT-2 solution of 0.5 % per kg soil). Into 

each observation points were studied daily the 

vegetation vessels (1- investigated soil, 2- mixture 

1:1, 3- mixture 2:1, 4- mixture 1:2, 5- mixture 1:3) 

treated with 0, 3 or 5 mL polyelectrolyte solution of 

0.5 % per kg soil. During the whole period of study 

was measured the height of vegetal species, with the 

mention that after the height of 10 cm, the grassland 

was mowed down for improving of grass strength. 

569


The worst results for soil series 0 and I were 

performed into A observation point (Table 4 and 5) 

(Zaharia et al, 2006). 

It can be seen that the growth of vegetal 

species on soil from the investigated site was lower 

than of soil mixtures. thus, the fertility efficiency can 

be improved by mixing the investigated soil with 

fertilized soil for necessary soil stabilization and with 

soil conditioning agent. 

The best results into soil series I were 

performed for soil mixture 1:3 (relay soil/ fertilized 

soil), and reference soil, followed by soil mixture 1:1, 

and relay soil. The relay soil was not the worst 

situation. This growing evolution is based on soil type 

and electric field impact of relays from Uricani- 

Valea Lupului, Iaşi. The vegetal species number and 

germination degrees for these treated soil samples 

with polymeric soil conditioning agent (series I) were 

measured or calculated (Table 6). 

It can be observed that the addition of 

commercial fertilized soil and polymeric conditioning 

agent had positive impact of vegetation growth. 

For the series II of vegetation vessels were 

used an other polyelectrolyte dose, and other 

operational regime: into 1 litter of water is added 5 

mL polyelectrolyte and 300 g soil. The mixture of 

aqueous soil suspension is agitated 30 minutes on a 

magnetic stirrer followed by separation of the two 

phases. The aqueous phase was eliminated (ca 75 %), 

and the soil was cultivated with grass species. The 

same operational procedure was applied for each soils 

or soil mixtures. The experimental data are presented 

in Table 7. 

The vegetation number and germination 

degrees for series II are presented in Table 8. 

The results are good enough for the soil 

mixtures but slow decreasing for relay soil, because 

of electric field impact, conditioning agent, and soil 

type (soil composition and characteristics). 

The comparison between the three series of 

experiments (series 0, I and II) was synthesized into 

Fig.1. 

Fig.1 The influence of polyelectrolyte dose on the 

germination degrees of grass species 

Table 5. Evolution of vegetal species growth into A point 

(60 m first relay), and daily irrigation (series I – 3 mL 

polyelectrolyte solution of 0.5 % / kg soil)) 

Day 

no. 

Relay 

soil 

Heights of grass species (mm) 

Mixture Mixture 

1:3 2:1 

(relay (relay 

soil/ soil/ 

fertilized fertilized 

sol) soil) 

Mixture 

1:1 

(relay 

soil / 

fertilized 

soil) 

Reference 

soil 

1-6 - - - - - 

7 - - 3 mm - 5 mm 

8 - 5 mm 10 mm - 15 mm 

9 5 mm 10 mm 18 mm - 25 mm 

10 15 mm 20 mm 28 mm 3 mm 40 mm 

11 28 mm 30 mm 40 mm 5 mm 60 mm 

12 40 mm 45 mm 55 mm 10 mm 70 mm 

13 60 mm 60 mm 75 mm 20 mm 90 mm 

14 73 mm 71 mm 88 mm 26 mm 96 mm 

15 80 mm 85 mm 95 mm 35 mm 98 mm 

16 85 mm 95 mm 100 mm 40 mm 102 mm 

17 90 mm 100 mm 102 mm 43 mm 105 mm 

18 95 mm 102 mm 105 mm 45 mm 107 mm 

19 103 108 mm 112 mm 47 mm 115 mm 

mm 

20 

120 mm 119 mm 130 mm 

The grass 

is mowed 

down for 

improving 

50 mm 130 mm 

The 

grass is 

mowed 

down 

of grass 

straight 

21 125 mm 130 mm 10 mm 50 mm 10 mm 

The 

grass is 

mowed 

down 

22 128 mm 10 mm 18 mm 52 mm 18 mm 

130 mm 20 mm 20 mm 60 mm 20 mm 

23 The 

grass is 

mowed 

down 

24 10 mm 25 mm 24 mm 70 mm 23 mm 

25 15 mm 29 mm 25 mm 80 mm 23 mm 

26 15 mm 30 mm 25 mm 80 mm 27 mm 

27 16 mm 31 mm 28 mm 82 mm 30 mm 

28 17 mm 31 mm 29 mm 85 mm 30 mm 

29 20 mm 35 mm 30 mm 90 mm 30 mm 

30 22 mm 36 mm 31 mm 100 mm 32 mm 

31 25 mm 38 mm 32 mm 105 mm 32 mm 

32 27 mm 39 mm 33 mm 111 mm 34 mm 

33 21 mm 37 mm 33 mm 114 mm 34 mm 

34 22 mm 40 mm 36 mm 117 mm 35 mm 

35 25 mm 42 mm 39 mm 122 mm 37 mm 

36 25 mm 44 mm 42 mm 127 mm 39 mm 

37 28 mm 46 mm 46 mm 

130 mm 

The 40 mm 

grass is 

mowed 

down 

38 30 mm 49 mm 48 mm 10 mm 42 mm 

39 32 mm 51 mm 50 mm 11 mm 45 mm 

40 37 mm 55 mm 52 mm 14 mm 50 mm 

41 39 mm 70 mm 53 mm 17 mm 52 mm 

42 42 mm 75 mm 55 mm 22 mm 52 mm 

43 44 mm 78 mm 56 mm 26 mm 55 mm 

44 45 mm 80 mm 58 mm 29 mm 57 mm 

45 47 mm 82 mm 60 mm 30 mm 59 mm 

570

Study of increasing soil fertility into a site with high electric field around using polymeric conditioning agent 

Table 6. Efficiency of vegetal species growth (investigated 

site, series I) 

Efficiency/ 

soil vessel 

Vegetal 

species 

number 

Germination 

degree, % 

Table 7. Evolution of vegetal species growth into A point 

(60 m first relay), and daily irrigation (series II – 5 mL 

polyelectrolyte solution of 0.5 % / kg soil) 

Heights of grass species (mm) 

Day Relay 1:1 1:3 Reference 2:1 

no soil 

soil 

1.... - - - - - 

8 

9 - 5 mm 8 mm 5 mm 5 mm 

10 - 10 mm 10 mm 8 mm 10 mm 

11 - 14 mm 18 mm 10 mm 15 mm 

12 - 20 mm 28 mm 20 mm 20 mm 

13 - 23 mm 40 mm 31 mm 26 mm 

14 - 28 mm 50 mm 43 mm 29 mm 

15 - 34 mm 70 mm 50 mm 32 mm 

16 5 mm 38 mm 85 mm 70 mm 38 mm 

17 10 mm 40 mm 97 mm 90 mm 42 mm 

18 20 mm 43 mm 105 mm 100 mm 50 mm 

19 30 mm 48 mm 115 mm 110 mm 50 mm 

20 40 mm 50 mm 125 mm 120 mm 52 mm 

21 

Relay 

soil 

1:1 

(relay 

soil/ 

fertilized 

soil) 

1:3 

(relay 

soil/ 

fertilized 

soil) 

40 mm 55 mm 130 mm 

The grass 

is mowed 

down for 

improving 

of grass 

2:1 

(relay 

soil/ 

fertilize 

d soil) 

33 42 59 24 60 

130 mm 

The grass is 

mowed 

down for 

improving 

of grass 

Reference 

soil 

20.12 25.61 36.98 14.63 36.59 

53 mm 

straight straight 

22 42 mm 60 mm 10 mm 10 mm 55 mm 

23 45 mm 70 mm 15 mm 15 mm 65 mm 

24 45 mm 78 mm 25 mm 23 mm 70 mm 

25 47 mm 85 mm 30 mm 29 mm 75 mm 

26 47 mm 90 mm 40 mm 40 mm 80 mm 

27 50 mm 112 mm 46 mm 45 mm 82 mm 

28 52 mm 120 mm 50 mm 50 mm 90 mm 

53 mm 130 mm 62 mm 60 mm 110 mm 

29 

The 

grass is 

mowed 

down 

30 55 mm 10 mm 70 mm 70 mm 120 mm 

31 

55 mm 15 mm 78 mm 77 mm 130 mm 

The 

grass is 

mowed 

down 

32 58 mm 20 mm 85 mm 85 mm 10 mm 

33 58 mm 25 mm 93 mm 93 mm 20 mm 

34 60 mm 33 mm 100 mm 100 mm 30 mm 

35 60 mm 40 mm 110 mm 110 mm 40 mm 

36 64 mm 45 mm 115 mm 115 mm 50 mm 

37 64 mm 50 mm 120 mm 120 mm 60 mm 

38 64 mm 50 mm 120 mm 120 mm 60 mm 

39 64 mm 55 mm 123 mm 122 mm 65 mm 

40 64 mm 57 mm 126 mm 125 mm 70 mm 

It seems that for the series II the germination 

degrees were almost twice times higher than of series 

I. The addition of soil conditioning agent favourites 

the increase of ability to support vegetation, 

particularly Raigras aristat species, into a site 

characterized by negative influence of high electric 

field on soil quality. 

The remediation of soil quality using the 

polymeric soil conditioning agent can be applied on 

the investigated site, but additional studies must be 

taken into consideration. 

Table 8. Efficiency of vegetal species growth (investigated 

site, series II) 

Efficiency/ 

soil vessel 

Vegetal species 

number 

Germination 

degree, % 


Relays 1:1 1:3 2:1 Reference 

Soil 

soil 

12 65 120 40 60 

7.32 39.63 73.17 24.39 36.59 

The soils from the investigated northern 

Romanian site with high electric tension around are 

not efficient supports for growth of Raigras aristat 

species because of the electric field around (e.g., 40 – 

70 V/m 2 for all investigation period), but also because 

of soil characteristics and meteorological condition on 

the site during the experiment period. 

The applications of synthetic PONILIT GT-2 

anionic polyelectrolyte as soil conditioning agent into 

the investigated site and high electric field around 

have positive impact on “soil quality” as support for 

vegetation species. 

The performed values for germination degree 

increase from 3.05 % to 12.20 % when was added 

fertilized soil, and respectively, 38.98-73.17 % when 

is added polymeric conditioning agent. Moreover, the 

experimental data concludes that the use of lower 

polyelectrolyte concentration is indicated (e.g., < 5 

mL polyelectrolyte solution of 0.5 % per 1 Kg soil). 

The negative environmental impact of high 

electric tension into the investigated site can be 

attenuated if is used a polymeric soil conditioning 

agent as the anionic polyelectrolyte based maleic acid 

and vinyl acetate. 

References 

Antohi C., Ivanov Dospinescu I., (2003), Radiation sources 

and protection technologies, Performantica Press, 

Iasi, Romania. 

Canarache A., (1990), Physics of agricultural soil (in 

Romanian), Ceres Press, Bucharest, Romania. 

Davidescu D., Calancea L., Davidescu D.V., Lixandru Gh., 

Ţârdea C., (1981), Agricultural chemistry (in 

Romanian), Didactic and Pedagogic Press, Bucharest, 

Romania. 

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European Commission, (2002), Towards a Thematic 

Strategy for Soil Protection. Communication from the 

Commission to the Council, the European Parliament, 

the Economic and Social Committee and the 

Committee of the Regions. Commission of the 

European Communities, Brussels 16 April 2002 COM 

(2002) 179. 

Guide Manual, (1993), Guide Manual for DRELL 

Spectrophotometer, Hach Company, 1991-1993. 

Surpateanu M., Zaharia C., (2002), ABC – Methods for 

analysis the quality of environment components (in 

Romanian), T Press, Iasi, Romania. 

Surpateanu M., Zaharia C., (2000), Technogenic Soils – a 

solution for environmental protection, Scientific 

Symposium: Actual and perspective problems into 

horticulture, vol.2: Scientific papers – XXXXIII, 

Series Horticulture, Ion Ionescu de la Brad Press, 

Iasi, 274-279. 

Tzilivakis J., Lewis K.A., Williamson A.R., A prototype 

framework for assessing risks to soil functions, 

Environmental Impact Assessment Review, 25, 

(2005), 181-195. 

Zaharia C., Ivanov Dospinescu I., Macoveanu M., (2006), 

The impact of high electric tension on soil fertility, 

Proceedings of International Conference UNITECH 

06, 24-26 November 2006, Gabrovo, Bulgaria, vol.III, 

p. III-359-III-363. 

Zaharia C., Surpăţeanu M., (2001), Spoil banks 

ecologization by recultivation, Proceedings of XVI-th 

National Conference for Soil Science, vol.III, 

Suceava, 23-28 august 2000, ”Al.I.Cuza” 

Universitary Press, Iaşi, 274-279. 

Zaharia C., (2005), Juridical Protection of the Environment 

(in Romanian), Ecozone Press, Iasi, Romania. 

572




______________________________________________________________________________________________ 

METHODS AND PROCEDURES FOR ENVIRONMENTAL 

RISK ASSESSMENT 

Brînduşa Mihaela Robu ∗ , Florentina Anca Căliman, Camelia Beţianu, 


“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 

Department of Environmental Engineering and Management, 71Mangeron Blvd., 700050 - Iasi, Romania, 

Abstract 

This work presents the state of the art of qualitative and quantitative risk assessment methodologies in a variety of fields. Because 

risk exists in all ranges of human activity, both private and professional, risk assessment is an attempt to analyze precipitating 

causes of risk in order to more efficiently reduce its probability and effects. Numerous methodological guidelines within the field 

of environmental science exist to provide guidance for a risk assessment program, although the level of verifiable quantitative 

data, such as specific chemical effects and scientifically proven hazards, make a direct transfer of methodologies impossible. The 

risk-assessments and their key principles detailed within can be also used to assist in the development of decision making process. 

The common notion of risk is associated with actions or decisions that may have undesired to outcome. This implies that the riskbased 

approaches focus on the negative impacts and their prevention. Risk assessment places the emphasis on the potential 

negative environmental impacts of an organization’s activities and allows the identification of indicators that directly reflect its 

efforts, efficiency and effectiveness in reducing or even preventing them. Risk assessment is one of the steps of the general risk 

management procedure. Risk management is a technique used to identify, characterize, quantify, evaluate and reduce losses from 

actions or decisions that may have undesired outcomes. The first step of the generic procedure involves the risk identification that 

is the systematic identification of all potential actions or decisions with undesired consequences that may result from the operation 

of an organization. The next step involves the risk assessment, while further steps address issues like the evaluation of risks in 

order to determine the organizations ability or willingness to tolerate their consequences in view of the associated benefits, and the 

selection and implementation of the most preferable approach for the reduction of unacceptable risks. Lately, the trend is to 

integrate the risk principle into impact assessment procedure, and reasons for that are: risk assessment (RA) provides a structured 

framework for dealing with uncertainty in the assessment of impacts being the subject of debates and concerns, especially, 

concerning impacts on public health; environmental risk assessment (ERA) is specifically developed to address health issues and 

contains elaborate techniques for enhancing health impacts assessment comprehension in environmental impact assessment (EIA); 

ERA emphasizes scientific quantitative approaches and techniques in impact identification and evaluation and for improving the 

technical background for decision-making; closer cooperation between the environmental impact assessors and risk assessors and 

creation the mixed expert team would allow for more effective information collecting into environmental assessment process; 

ERA can be applied not only at the stage of impact prediction and evaluation, but also during project implementation and postclosure 

stages (over the whole project life cycle). 

Keywords: environmental risk assessment, models for risk assessment, event-tree risk analysis, HAZAN, HAZOP, integrated 

environmental impact and risk assessment 

1. Environmental evaluations into decision making 

process 

Probably the most frequently argued thesis 

in environmental evaluation is that public perceptions 

have no place in environmental policy decisions 

because laymen do not have the knowledge to 

evaluate accurately what may be the changes and 

consequences in the environment due to a certain 

(development) action, or what is best for society. 

Thus, the resulting judgments on alternatives and 

their acceptability will be subject to noise or bias. 

∗ Author to whom all correspondence should be addressed: e-mail brobu@ch.tuiasi.ro

Robu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 573-592 

Analyses performed by experts should be 

free from such errors (Barrow, 1997; Calow, 1998). 

Nevertheless, besides an ethical foundation, one of 

the main reasons why the public should also be 

involved in the environment related decision making 

process is that the science itself is not capable of 

answering crucial questions regarding environmental 

valuation (O’Connor and Splash, 1999). 

A fact which undoubtedly supports openness 

and transparency in environmental decision-making is 

the uncertainty of predictions of impacts (Morris and 

Therivel, 1995; Robu, 2005). It is often said that 

prediction is difficult, especially concerning the 

distant future. The response of science to uncertainty 

is routinely framed in the language of probability 

theory, but such probabilities are rarely ‘pure’. The 

risk analyst typically needs to invoke a variety of 

assumptions and hypotheses in order to estimate the 

impacts and their corresponding probabilities. Also, 

situations where one has to apply value judgments, 

preferences and expert opinion as inevitable 

components of the evaluation process are not 

exceptional (Andrews, 1988; Barrow, 1997; Cooke, 

1991). 

The common notion of risk is associated 

with actions or decisions that may have undesired to 

outcome. This implies that the risk-based approaches 

focus on the negative impacts and their prevention 

(Hokstad and Steiro, 2006). Risk assessment places 

the emphasis on the potential negative environmental 

impacts of an organization’s activities and allows the 

identification of indicators that directly reflect its 

efforts, efficiency and effectiveness in reducing or 

even preventing them. Risk assessment is one of the 

steps of the general risk management procedure. Risk 

management (Lalley, 1982; Kolluru et al., 1996; 

Aven and Kristensen, 2005) is a technique used to 

identify, characterize, quantify, evaluate and reduce 

losses from actions or decisions that may have 

undesired outcomes. The first step of the generic 

procedure involves the risk identification that is the 

systematic identification of all potential actions or 

decisions with undesired consequences that may 

result from the operation of an organization. The next 

step involves the risk assessment, while further steps 

address issues like the evaluation of risks in order to 

determine the organizations ability or willingness to 

tolerate their consequences in view of the associated 

benefits, and the selection and implementation of the 

most preferable approach for the reduction of 

unacceptable risks (Kolluru et al., 1996; Karrer, 

1998). 

Risk assessment, in general, refers to the decision 

making as far as the viability of a system is 

concerned, where the term system refers to any 

potential infrastructure (e.g. industry, bridge, software 

system, etc.). The viability of a system depends on the 

requirements upon which it has been built, which 

implies that a significant volume of information 

should be gathered in order to examine whether these 

requirements have been satisfied (Andrews, 1988; 

Den Haag et al., 1999). For a rational decisionmaking 

regarding the risk assessment and the 

satisfaction of the system’s requirements, the 

following should be considered (Barrow, 1997; 

Christou and Amendale, 1998): 

• the requirements and goals that have been set 

at the strategic planning of the system; 

• the probability of failure to achieve the goals 

that have been set; and 

• the consequences resulting from any failure to 

achieve the goals that have been set. 

Environmental Impact Assessment (EIA) aims to 

predict environmental impacts at an early stage in 

project planning and design, find ways and means to 

reduce adverse impacts, shape projects to suit to the 

local environment and present the predictions and 

options to decision-makers, while the life cycle 

assessment (LCA) is estimating environmental 

burdens for energy and materials used and wastes 

released into the environment, and identifying 

opportunities for environmental improvements. The 

assessment includes the entire life cycle of the 

product, process or an activity starting from 

extraction (or excavation), processing, manufacturing, 

transportation, distribution, use, recycle, and final 

disposal. The LCA guides regulatory agencies and 

other stakeholders for decision-making in design, 

selection and evaluation of a process. It may be used 

to evaluate the environmental impacts of a segment 

within a product or process’s life cycle where the 

greatest reduction in resource requirements and 

emissions can be achieved. By using EIA and LCA 

both, environmental and economic benefits can be 

achieved, such as reduced cost and time of project 

implementation and design, avoided treatment/cleanup 

costs and impacts of laws and regulations 

(http://www.uneptie.org/pc/pc/tools/pdfs/EIA2- 

rpt.pdf). 

2. Risk assessment – tool of environmental 

management system 

To evaluate the quality of environmental 

components (air, water, soil, and human health), 

environmental management applied tools as risk 

assessment (RA), environmental impact assessment 

(EIA), life cycle assessment (LCA). EIA has tended to 

focus on the identification of impacts associated with 

planned activities or projects (Demidova, 2001; Robu, 

2005), whereas environmental risk assessment (ERA) 

involves a rigorous analysis of those impacts: the 

calculation of the probability, and magnitude of 

effects (Robu and Macoveanu, 2005a,b). The reasons 

for integrating RA and EIA into one analytical 

procedure are of big interest (Jaeger, 1998; Robu, 

2005): 

- RA provides a structured framework for 

dealing with uncertainty in the assessment of impacts 

being the subject of debates and concerns, especially, 

concerning impacts on public health; 

- ERA is specifically developed to address 

health issues and contains elaborate techniques for 

574


enhancing health impacts assessment comprehension 

in EIA; 

- ERA emphasizes scientific quantitative 

approaches and techniques in impact identification 

and evaluation and for improving the technical 

background for decision-making; closer cooperation 

between the environmental impact assessors and risk 

assessors and creation the mixed expert team would 

allow for more effective information collecting into 

environmental assessment process; 

- ERA can be applied not only at the stage of 

impact prediction and evaluation, but also during 

project implementation and post-closure stages (over 

the whole project life cycle). 

Environmental impact and risk assessment 

consider human health and environmental 

components issues from different aspects. For this 

reason one can assume that the integration of risk 

assessment (RA) and environmental impact 

assessment (EIA) is a complex issue, which deserves 

to be considered from different aspects. The 

assessment of the risk may be realized through the 

use of either qualitative or quantitative methods 

(Karrer, 1998; Tixier et al., 2002). 

The use of qualitative methods requires a 

sound level of knowledge and experience, while the 

use of quantitative methods requires a significant 

level of reliable information. The application of a 

qualitative method provides a better understanding of 

the system’s performance from the very beginning, 

even before any quantitative information become 

available. A quantitative method, on the other hand, 

allows the quantification and more precise estimation 

of the probabilities and the potential negative 

consequences. The best approach is the combination 

of both qualitative and quantitative methods. 

The final output from risk assessment is an 

estimated measure of risk (Khan and Haddara, 2003). 

However, the process also provides a good 

understanding of the way the consequences of any 

failure to achieve a goal may reach and affect the 

environment. When risk assessment is constructed in 

a good and comprehensive way, it may go even 

further and include social and political consequences 

of environmental incidents, thus indicating short and 

long-term negative business impacts like the loss of 

brand loyalty, customer loyalty and corporate image 

(Karrer, 1998). 

The application of risk management tools aid 

in selection of discreet, technically feasible and 

scientifically justifiable actions that will protect 

environment and human health in a cost-effective 

way. The risk based on life cycle assessment 

(RBLCA) is a process of weighting policy alternatives 

and selecting the most appropriate action by 

integrating the environmental risk assessment with 

social, economic, and political attributes to reach a 

decision (Sadiq and Khan, 2006). 

The RBLCA will choose the alternatives, 

which cause minimum environmental damages and 

evaluate the costs and benefits of proposed risk 

reduction programs. 

The RBLCA may integrate sociopolitical, 

legal and engineering factors to manage risks and 

environmental burdens of a process. The RBLCA 

considers human health, ecological, safety and 

economical risks information, which may involve 

preferences and attitudes of decision-makers (Sadiq 

and Khan, 2006). 

The LCA starts with the identification of 

environmental hazards expected at various units 

(AICE, 1992). These hazards are due to the chemical 

compounds involved in the process that upon release 

adversely affect to humans or to the environment. It 

also includes hazard due to severity of operating 

conditions like temperature and pressure. The 

chemical hazards are not limited to process chemistry, 

rather they include cleaning solvents, heating and 

cooling agents, and all other chemicals involved in 

any part of the process. Generally, environmental 

impact and risk assessment (EIRA) examines the 

potential and actual environmental and human health 

effects from the use of resources (energy and 

materials) and environmental releases. An EIRA 

includes as main steps the followings: classification, 

characterization, and valuation. 

3. Procedures for risk assessment 

3.1. General considerations 

The environmental risk is the result of the 

interactions between the human activities and the 

environment. The ecologic risk management that 

refers to the problematic of the risks generated by the 

past, present and future human activities on flora, 

fauna and ecosystems constitutes only a part of the 

environmental risk management. 

The environmental risk management is 

framed within two categories (Barrow, 1997): 

Environmental risk: this type of risk admits 

the fact that the activities of an organization may 

generate certain environmental changes. The 

environmental risk refers to the: 

• Flora and fauna 

• Human health and economic wealth; 

• Human social and cultural wealth; 

• Water, air and soil resources; 

• Energy and climate. 

Risk for organization, from the point of view 

of environmental problematic: this category includes 

the risk of non-conformation with the legislation and 

current or future criteria. In this category are also 

enclosed the casualties in organization business 

registered from an inadequate management, 

deterioration of the company credit, costs of lawsuits 

and difficulties to ensure or least to maintain the 

possibility to continue the operation and development 

activities. The problems concerning the work safety 

and health as well as the risk management in 

emergency situation may be significant from the 

environmental risk point of view. 

575


The environmental risk management provides a 

formal set of processes that constitutes the fundament 

for environmental decision making and support the 

decision factor in the steps of incertitude level 

minimization. 

3.2. Qualitative risk assessment 

3.2.1. Control list 

Control list, generally, identifies known, 

predictable risks and refer to standards. The following 

techniques are used: 

• DSF – “Diagnosis Safety Form” is based on a 

questionnaire containing 50 questions concerning 

problems related to technical equipment, 

environment, production planning etc. 

• DCT – “Diagnostique et Conditions du Travail” 

contains a questionnaire similar to the above 

described one, but in this case the evaluation is 

performed in three stages: good, average and 

poor; 

• SQD – “Safety Diagnosis Questionnaire” has as 

purpose the identification of the critical situations 

concerning the incompatibilities between 

technical and organizational conditions, on a 

hand, and the safety requirements of the activities, 

on the other hand. 

• MORT – “Management Oversight and Risk 

Three” uses a questionnaire containing around 

300 questions with optional answers. It is focused 

on human activities and was conceived with the 

aim at significantly enhance the performances 

regarding the system safety. 

3.2.2. Integral inspections of the industrial units 

Within current interpretation, the integral 

inspections emerged as a necessity to develop the 

measurable characteristics of the safety systems 

performances. These inspections give useful 

information on the activities concerning design, 

construction, starting-up, operation, closing in, 

disassembly and storage of the plant components. The 

integral inspections take places on three levels, the 

operators, experts and authorities having specific 

tasks (Gavrilescu, 2003): 

• constant inspection of the plant and its 

components operation by the process managers 

and inspectors entrusted with special tasks; 

• initial and periodic inspections at pre-established 

intervals by independent experts, eventually from 

the exterior of the system; 

• announced inspection of the local authorities in 

order to issue the working license, as well as not 

announced inspections. 

In close relation with plant inspections is the 

audit that represents, in broad sense, an independent 

investigation of the activities in field and constitutes a 

part of the management system of plant safety. This 

involves a program containing systematic questions 

(clearly formulated and addressed to the person 

responsible for plant units), answers evaluation and 

action plan defining. 

3.2.3. Ranking 

Ranking refers to identification of danger 

sources in designing phase or comparison of the 

plants situated on a working industrial platform. 

There are thus, quantified the potential risk sources 

by conferring corresponding levels of importance and 

establishing prevention measures. 

3.2.4. Preliminary Hazard Analysis (PHA) 

PHA focuses on the regions were hazardous 

materials are concentrated, as well as on the main 

units, monitoring the places where it is possible to 

result uncontrolled hazardous substances leakages or 

energy losses. The main considered points are: 

• used substances in the process and potential 

danger; 

• system units; 

• interfaces between system components; 

• environment; 

• system operations; 

• endowments; 

• safety equipments. 

3.2.5. “What if” Method 

This method is based on iteration of some 

series of questions that lead to identification of the 

unexpected events with eventual unfavorable 

consequences and is applied on specific activity fields 

(Gavrilescu, 2003). 

A. Analysis of the faults, effects and critical states 

This analysis may be done at both qualitative 

and quantitative levels and focuses on plant/system 

components. It is based mainly on elaboration of a 

table, which contains: 

• equipment position, name and description; 

• faulting ways; 

• consequences; 

• assignment of critical coefficients on a 

conventional scale previously established. 

The algorithm of the method involves the 

following steps: 

• defining of the system; 

• identification of the faulting way; 

• analysis of the faulting causes; 

• analysis of the faulting effects; 

• analysis of the compensation possibilities; 

• assessment of the risk associated to each 

faulting way; 

• proposals for remediation and prevention 

measures. 

In the first stage, the main and secondary 

functions, the role of the components, the working 

related interdictions and the acceptable working 

limits are established; there are also elaborated the 

flow sheets for clarifying the interconnections 

between the components. 

576


In the second stage, the framing within one 

of the following 5 faulting ways is foreseen: 

• blocked at zero – breaking of a connection, 

short-circuit; 

• degradation – pipe cracking, plant mechanical 

weakening; 

• intermittent switching-out –electronic elements 

working accidentally; 

• undesired secondary effect. 

The third stage is developed concomitant to 

the identification of faulting ways. The material 

components (technological equipments- wear and 

deformation) and energetic fluxes inserted by the 

respective component are studied. The effects 

analyzed in the forth stage are classified in local (at 

the level of the component that is damaged) and 

general (at the level of the whole system). 

The analysis of the effect compensation 

possibilities consists in: 

• reduction of the fault occurrence possibility 

(safety devices, preventive maintenance); 

• diminution of the propagation effects in the 

system (components doubling, signaling devices); 

• reduction of the consequences (use of the 

protective means). 

In the sixth stage, the assessment of the risk 

associated to each fault way is done in relation to the 

severity (G) and probability (P). The qualitative 

analysis assigns scores on the scale 1 - 6: 

For severity level: 

Ignorable – does not involve working accidents or 

material damages; 

Marginal – admits corrective measure for 

preventing the working accidents or material 

damages 

Serious – needs urgent measures 

Major – serious working accidents or system 

damages 

Major - serious working accidents or system 

damages at the company level 

Major – serious working accidents or system 

damages exceeding the company level. 

For the probability level: 

Extremely rare - p 10 -2 . 

In the case when combination (G – P) has 

the following values: 4 – 5; 4 – 6; 5 – 4; 5 – 5; 5 – 6; 

6 – 3; 6 – 4; 6 – 5; 6 – 6, the risk is considered as 

being unacceptable. Finally, remediation measures 

are proposed with the aim at minimizing the risk (risk 

management). For unacceptable risks primary, 

secondary and tertiary measures are proposed 

(referring to the la possibilities to control the accident 

consequences). 

B. Analysis of human errors 

The human errors defined as mistakes, lack 

of concordance between perception and objective 

reality confirmed by the practice are inevitable and 

not predictable. For this reason, it is very expensive to 

ensure the safety due to the difficulty to anticipate the 

multitude of the possibilities to affect the 

process/plant/system safety through negligence or 

fatigue. However, one may apply elaborated packages 

of prevention measures for diminishing the human 

contribution to the major accidents if the type of 

possible error is known. 

A classification of the human errors could be 

the following: 

• Errors appeared due to a moment of lack of 

attention; 

• Errors owed to an improper 

instruction/training; 

• Errors owed to weak mental and physic 

abilities of the operator; 

• Errors appeared due to wrong decisions; 

• Errors committed by managers. 

3.2.6. HAZOP method 

The objectives of the HAZOP (hazard 

operability) methods are (Crawley, 2000): 

• Identification of the hazard locations, 

• Ascertainment of the project particularities 

that lead to identification of the probabilities 

of some undesired events occurrence, 

• Establishment of the necessary information for 

design from the perspective of ensuring the 

plant reliability, 

• Initiation and development of quantitative 

studies related to hazard and risk. 

Traditionally, the safety in chemical plant 

design is based on designing and exploitation codes, 

as well as on control lists achieved by using 

experience and knowledge of the experts and 

specialists from industry. Unfortunately, such 

approaching may solve only existing problems. Once 

the complexity of modern plants increased, these 

traditional methods lost their importance, being 

considered that their application in design phase is the 

most recommendable (Crawley, 2000). 

HAZOP was elaborated as an applied 

technique for systematic identification of the potential 

hazards and operation problems in the new plants. 

Through HAZOP, a critical examination of the plants 

or processes by an experimented team is done in 

order to identify all the possible deviation from a 

certain project alongside the undesired effects on 

safety, operation and environment that would appear. 

The possible deviations are found by using rigorous 

questionnaires, containing key-words, applied to the 

analyzed project. 

The success or the failure of the study 

depends on: accuracy of the project or of other data 

used for the study; technical skills or experience of 

the team; ability of the team to use the method as 

577


support for prediction of the possible deviation, cause 

and consequences. HAZOP will be beneficial during 

design or assembly of new a plants/process or during 

major modifications of the existing one; when hazard 

for environment/quality or problems of costs 

associated with operation appear; after a major 

incident that implies burning, explosions, toxic 

substances leakage; when must be explained why an 

industrial or practice code cannot be followed (AICE, 

1992; Gavrilescu, 2003). 

3.3. Quantitative risk assessment 

3.3.1. Analysis 

HAZOP studies are able to identify the 

hazard but do not provide quantitative information on 

the values referring to the probabilities to occur 

events that lead to undesired consequences. Many 

events are needed to join for resulting in the 

occurrence of an incident as damage of the process 

units and equipments or systems of control, improper 

operation etc. Thus, sequences of chain events that 

would results in appearance of hazardous incidents in 

the shape of logic trees may be defined, such as 

events tree (ET), and fault tree (FT), respectively. 

Among the common stages of the risk 

quantitative analysis, assessment of frequency 

(probability) refers to three main components: 

acquiring of information from similar situations 

previously occurred, elaboration and analysis of the 

logic tree, analysis of the damages resulted in 

common situations. ET and FT are logic schemes, 

which describe the course of the possible events as 

well as their combination. The former starts from 

certain undesired events and goes further by upward 

exhibiting the evolution of all identifiable and 

possible situations in the shape of a tree. The fault 

tree starts from a damage and follows the cause-effect 

system up to exhaust of all foreseen events. The 

previous experience inserted in data bases with a 

multitude of possible scenarios and values of the 

probabilities calculated considering the nature of 

hazard, is used in this stage. 

Briefing, any HAZAN (hazard analysis) consists in 

three stages: 

1. Assessment of the frequency of the accident 

recurrence; 

2. Assessment of the consequences upon the 

employees, local community and 

environments or equipment and profit; 

3. Comparison of the first two stages with a 

target or criteria in order to decide if the 

hazards are severe and what measure should 

be taken for reducing the possibility of 

accident occurrence. 

The methods used in the first stage are 

probabilistic. It should be assessed how often the 

incident may take place, as well as when it may not 

happen. The methods used in the second stage are 

partially probabilistic and partially deterministic. For 

example, in the case of flammable gas loss, only the 

probability of its ignition can be estimated. If this 

happen, the radiant heat as well as its loss with the 

distance may be assessed (deterministic). 

The damage of the equipments or the errors 

in operation of a process emerges as a result of the 

complex interaction between the components. The 

general probability of faults within a process is 

strongly dependent by the nature of the error. 

• Hazard Frequency (H) – number of events per 

year that determine the hazards occurrence. For 

example, the frequency of pressure increasing 

toward the value established when the reactor 

was designed. 

• Protection systems – systems that are specially 

installed for hazards prevention (for example, 

safety valves). 

• Testing Interval (T) – the protection systems 

should be tested for establishment of the response 

capacity concordant to technical 

recommendation. T is the interval of time 

between two successive tests. 

• Demand frequency (requests of use) (D) – 

frequency (occasions/year) of demanding a 

protection system. For example, frequency of 

reaching the level of safety valve loading by the 

pressure. 

• Fault frequency (f) – frequency (occasions/year) 

of working faults appearance in the case of a 

protection system. For example, a safety valve 

may break down at the normal operation 

pressure. 

• Dead-time fraction (fdt) – fraction of time when 

the protection system is not active. Probability 

not to function when a need exists. If the 

protection system is continuously operated, the 

hazard frequency H is zero. The hazard occurs 

when the demand of use of the protection system 

appears in a dead-time: H = D x fdt. 

3.3.2. Fault Tree Analysis 

The damages or the faults may be classified 

in: 

• primary damages, which emerge in the designed 

working conditions of the equipment; 

• secondary damages that appear in situations for 

which the system was not designed; 

• command damages for the case when the system 

works properly but in the wrong place and 

moment. 

The stages of elaboration of the fault tree 

are: 

• defining a top event, as for example, loss of gas 

ammonia form the storage tank: 

no…warehouse….plant…during normal 

working conditions; 

• defining the limits of the system subjected to 

analysis; 

• elaboration of the tree taking into account the 

following rules: 

578


o inside the contour of the events signs, their 

description is inserted without directly 

linking two connections (the events will be 

described after each connection); 

o the tree is elaborated on levels, downward 

from the top; 

o a level is constituted by an array of 

connections situated at the same distance 

by the top event and the prior events of the 

respective connections; 

o it is not allowed to go to the next level until 

the current event is exhausted. 

• solving of the free tree involves finding of 

minimal sequences. A sequence represents an 

array of events that results in an accident. The 

minimal sequences are successions of this type 

that contain a minimum number of events. 

Before properly accomplishment of the tree, 

the following steps should be done: 

• Defining of the top event (e.g. high 

temperature from the reactor). 

• Defining of the determinant event: conditions 

of occurrence. 

• Defining of the not-allowed events: damages 

at the system for power supply, faulting of the 

switches etc. 

• Defining of the physical conditions of the 

process: the limits should not be taken into 

account. For example, in elaboration of FT, the 

units situated upstream and downstream of the 

reactor will not be considered. 

• Defining of the configuration of the 

equipments from the system. 

• Establishment of the detailing level. 

After completion of these steps, one may 

proceed to the properly elaboration of the fault tree. 

First, the top event is drawn in the upper part of the 

scheme. This will be labeled precisely for avoiding 

the further confusions. Then, the major events that 

contribute to achievement of the top events should be 

identified. If these occur in parallel, will be linked 

through an AND connection. If they occurs in series, 

will be connected through OR. 

3.3.3. Event Tree Analysis (ETA) 

ETA is an inductive logic model that 

identifies the possible results of a given initiating 

event. An initiating event will commonly result in an 

accident or an incident. 

ETA considers the responses of the operators 

and safety systems to an initiating event. This 

technique is the most suitable for analysis of complex 

processes that involve few safety systems or 

emergency procedures. 

The first stage in conceiving an event tree is 

the defining of an initiating event that may lead to the 

damage of the system: equipment or utilities faulting, 

human error, natural disasters. The next step is the 

identification of the intermediate actions for removal 

or reduction of the initiating events effects. 

The event tree contains two branches for 

every intermediate event, one for a successful 

exploitation and other for a faulty exploitation of the 

system. The upper part represents the success, while 

the bottom part represents the failure. Within a 

simplified model, the initiating events become the 

damage of P2. There are some response stages at the 

initiating event that include the warning alarm for the 

minimum flow rate, the response of the operator and 

damage of P1. 

The assessment using the event tree analysis 

contains the following steps (an example): 

1. equipment is damaged and becomes the 

initiating events. Probability of this event 

was defined as being 1. 

2. The warning alarm for minimum flow at the 

vessel may work or fail. If it works, the 

upper branch is covered. If it doesn’t wok 

the bottom branch is covered. The warning 

has a success probability of 0.998. 

3. The operator either respond or not to the 

warning alarm. Probability of responding is 

0.952. 

4. The last response is the fact that the operator 

put the equipment into operation. Probability 

of this event is 0.995. 

The event tree analysis is the best analysis 

for the initiating event that may lead to the final effect 

of the event. Each branch of the tree constitutes a 

separate sequence of the relationships between the 

safety functions of the initiating event. Considering 

the same system and the same hypothesis concerning 

the probabilities, identical results may results through 

the both methods. 

The fault tree is larger then the events tree 

owing to the fact that the latter is based on a single 

effect related to the damage. Many people are 

tempted to think in a logic manner about the safety 

systems using the events tree approaching. Risk 

assessment throughout the tree event may be 

summarized as follows (Gavrilescu, 2003): 

• identification of the initiating events that may be 

materialized in accidents; 

• identification of the safety functions for 

diminishing the initiating events; 

• elaboration of the event tree; 

• description of the results of an accident and its 

probability. 

3.4. Environmental risk assessment in accordance to 

MAPPM Order no. 184/1997 

The environmental risk assessment 

(concordant to Ministerial Order no. 184/1997) 

examines the probability and the severity of the main 

components of an environmental impact. The 

necessity of additional information regarding the risks 

related to the identified pollution or to the pollutant 

activities developed on a site may determine the 

579


environmental competent authority to request a risk 

assessment with the aim at evaluating the probability 

of harm and at finding the possible prejudiced 

entities. Not every site affected by a certain pollutant 

will exhibit the same risk or will need the same level 

of remediation. The risk assessment is defined by the 

World Bank as being a process for identification, 

analysis and control of the danger appeared due to 

the presence of a hazardous substance into a plant. 

The Report from 1992 of the British Royal Society 

explains the sense of the definition given in the 

Directive European Commission 93/67/EEC, 

enlightening the components of risk assessment, 

meaning the risk estimation and calculus. 

In consequence, the risk assessment involves 

an estimation (including the identification of the 

hazards, the magnitude of the effects and the 

probability of occurrence) and a calculus of the risk 

(including the quantification of the danger importance 

and consequences for humans and/or environment). 

Risk assessment aims at controlling the risks 

produced on a site by identification of: 

• Pollutant agents or the most important 

hazards; 

• Resources and receptors exposed to the risk; 

• Mechanisms of risk accomplishment; 

• Important risks that emerge on the site; 

• General measures needed for reduction of 

the risk to an accepted level. 

The risk depends on the nature of impact 

upon the receptors but also on the probability of the 

occurrence of this impact. Identification of the critical 

factors that influence the relationship source-pathreceptor 

involves the detailed characterization of the 

site from physical and chemical point of views. 

Generally, the quantitative risk assessment 

encloses five stages: 

• description of the aim; 

• identification of the hazard; 

• identification of the consequences; 

• estimation of the magnitude of the 

consequences; 

• estimation of the probabilities of the 

consequences. 

Concordant to Order to 184/1997, the risk is 

the probability that a negative effect to occur in a 

specified period of time and is often described by the 

relation: 

Risk = Danger x Exposure 

The risk assessment implies the 

identification of the hazard and of consequences that 

may appear as a result of occurrence of the events 

considered as risk sources. In function of the 

importance of the consequences one may decide if 

there is necessary or not to take remediation 

measures. Concordant to the Order no. 184/1997, the 

risk quantification is based on a simple system of 

classification, where the probability and severity of an 

event are descendent distributed, being assigned with 

an arbitrary score: 

Simplified model 

Probability Severity 

3 = high 3 = major 

2 = medium 2 = medium 

1 = low 1 = insignificant 

This model is used not only for qualitative, 

but also for quantitative risk assessment. Thus, the 

risk may be calculated by multiplying the two factors 

(probability, severity) in order to obtain a 

comparative number, for example 3 (high probability) 

x 2 (medium severity) = 6 (high risk). This allows the 

comparison of different risks. 

The greater the results, the bigger the priority 

should be given to risk control. This basic technique 

may be developed for allowing more serious analysis 

by increasing the range of the scores for classification 

and by considering a bigger number of improved 

definitions for major severity, increased probability 

etc. When a big number of important pollutants are 

considered for assessment, an increased attention 

should be paid to a clearer manner of presentation. It 

is often necessary to summarize the information as a 

control list or matrix. 

4. Quantitative risk analysis for port hydrocarbon 

logistics 

4.1. Brief review 

Over the last few decades much experience 

has been gained in the field of risk analysis of 

standard chemical or petrochemical plants. 

Nowadays, this knowledge is being applied to a wide 

range of industrial activities involving hazardous 

materials handling, including ports (Crowl, 2002, 

Gavrilescu, 2003; Robu, 2005). Nevertheless, few 

works approached the application of QRA to 

navigational aspects and terminal operations are 

available, and this is to the role played by SEVESO II 

Directive. This method allows quantitative risk 

analysis (QRA) to be performed on marine 

hydrocarbon terminals sited in ports. A significant 

gap is identified in the technical literature on QRA for 

the handling of hazardous materials in harbors 

published prior to this work Ports are environments 

often overloaded with hazardous materials, both in 

bulk and containerized. 

The method described here is proposed 

within a Spanish project called FLEXRIS and applied 

to the premises of the port of Barcelona, one of the 

largest ports on the Mediterranean Sea (Ronza et.al., 

2006). Several risk assessment reports, made 

available to the public, proved to be a valuable source 

of information. What these works lack is an attempt at 

standardizing the process of risk assessment of 

navigation and loading operations for a generic 

port/terminal. 

580


4.2. QRA – method description 

Only liquid hydrocarbons are considered in 

this method. Moreover, only bulk transportation and 

handling are included within the scope of the research 

project mentioned above. The analysis covers port 

waters (from port entrance to berths) plus (un) 

loading terminals. Accidents occurring during the 

external approach of the tankers to the port are not 

take into account, nor are land accidents, such as 

those that can take place during storage and land 

transportation (within and outside the confines of the 

port). Finally, possible sabotage related scenarios and 

accidents likely to occur during tanker maintenance 

operations are excluded from this analysis. Instead, 

navigation through port waters and discharge are 

specifically addressed (Ronza et.al, 2006). 

4.2.1. Data collection 

The first step is to gather the relevant data 

that are used further during the analysis (Fig.1). This 

is a very important phase and ensuring that it is 

carried out properly can save great deal of time and 

avoid rough approximations. The data needed to be 

collected are (Ronza et.al., 2006): 

• The geographical location of the port; 

• A detailed map of the port; 

• Climate data; 

• Technical data on berths and (un)loading 

locations; 

• Physical and chemical data for the 

hydrocarbon products taken into account; 

• Traffic data (critical for the calculation of the 

frequency of accidents); 

• Duration of (un)loading operations; 

• Tanker hulls; 

• Data about the past accidents that above 

occurred in the port involving hydrocarbons. 

4.2.2. Scenario 

From a general point of view, only two basic 

events can cause a loss of containment during 

aforementioned operations: hull failure and loading 

arm/hose failure. For every loss of containment, two 

fold possibilities are considered: 

• In the case of hull failure, a minor as well as a 

massive spill; 

• For loading arms, partial and total rupture. 

In a general application, the number of 

scenarios is as follows: 

Number of scenarios = 4n+2m 

n being the number of hydrocarbons products traded 

and m the number of products bunkered (usually 

m=2, diesel oil and fuel oil being the bunkered fuels). 

4.2.3. Frequency estimation 

The approach was to estimate accident 

frequencies on the basis of both traffic data and 

general frequencies from literature. This method 

considered that the arm scenarios are of purely 

punctual natures, and hull ruptures are both punctual 

and linear. The authors (Ronza et.al., 2006) made 

remark that in fact the latter nay be caused be any of 

the following: 

• An external impact (ship – ship or ship – land) 

while the tanker is moving towards the berth or 

from the berth to the port entrance (linear option); 

• By an external impact (ship – land) during 

maneuvers near the (un)loading berth or a ship – 

ship collision while the tanker is (dis)charging 

(punctual operations). 

The dual nature must be taken into account 

because while the physical effects of the accident are 

practically the same, their consequences on people 

and installations may be different. Also, it is 

important to calculate separate the frequencies for 

punctual and linear scenarios. 

4.2.4. Event tree analysis 

The next step is to draw proper event trees 

and assign numerical probabilities to each of their 

branches. It was drown only n event trees, n being the 

number of hydrocarbon products analyzed. The event 

tree from Fig. 2 was used by authors (Ronza et.al., 

2006) in the application of the method to the Port of 

Barcelona. 

4.2.5. Consequences analysis 

The phenomena or quantities used by 

authors in the consequences analysis, needed to be 

modeled are: 

• Liquid release; 

• Evaporation rates 

• Burning rates 

• Pool fire radiation 

• Jet fire radiation 

• Cloud dispersion 

• Oil spill evaluation. 

Individual risk was assessed using the 

vulnerability correlations ((Ronza et.al., 2006). An 

additional criterion was adopted that is currently 

widely accepted: in the case of flash fires, 100% 

lethality was assumed for the area occupied by the 

portion of gas cloud in which the concentration is 

greater that the lower flammability limit, while 

outside that zone, lethality is assumed to be zero. 

4.2.6. Estimation of the individual risk 

The societal risk was estimated by building 

on the general procedures. The individual risk at a 

point (x, y) is expressed by the following equation: 

2π 

6 

∫ ∑ 

R ( x, 

y) 

= fRF ( x, 

y) 

p( 

θ ) p dθ 

(1) 

θ = 0 k = 1 

kθ 

where θ represents the wind direction, k stands for 

stability class, f is the accident frequency, RF kθ (x,y) 

the lethality function estimated on the basis of the 

vulnerability criteria, p(θ) the probability that the 

wind will blow in the direction θ and p k is the 

probability of the class of stability k. 

k 

581


Fig.1. Diagram of the QRA method (n = number of hydrocarbons products handled; m = number of hydrocarbon products 

bunkered) (Ronza et al., 2006) 

582


Initiating 

event 

Upward 

release 

Immediate 

ignition 

Delayed 

ignition 

Flame front 

acceleration 

Final 

events 

Overall 

probabilities 

Fig. 2. Event tree diagram 

4.2.7. Estimation of overall risk for population 

By integrated the product of R by the local 

population density over spatial coordinates, the global 

risk for a given accident scenario is obtained. By 

adding up the several R functions (one of each 

scenario), a global risk function is obtained. In order 

to estimate the number of injuries and evacuated 

people, historical data were used. The average ratios 

of injured people/evacuees to fatalities have been 

estimated to the followings: 

• 2.21 injured people for each fatality, 

• 220 evacuees for each fatality. 

This data were obtained from processing of 

1033 port area accidents from which only 428 

occurred during bulk hydrocarbon (un)loading and 

tanker movement/maneuvers were retained. 

The general ration should be used whenever 

the present QRA conceptual approach is applied to a 

port, because the scenarios, as they have been 

designed and structured, entail both (un)loading and 

ship maneuver/ approach operations. Nevertheless, 

the operation specific values can be used for studies 

that focus on a particular stage in port hydrocarbon 

logistics. 

5. Mathematic models for environmental analysis 

and assessment 

The modeling of the environmental systems 

is a very difficult problem owing to their complexity, 

as well to the complexity of their interaction with 

different other systems, interaction that is sometimes 

hard to be defined. In this paper, two environmental 

mathematic models are described. 

The first is a probabilistic model for risk 

evaluation that uses a repartition function for a 

random vector that describes the concentrations of the 

atmospheric pollutant factors. The latter is an 

optimization model based on multiple criteria, to 

appropriate financial funds for pollution reduction. 

For the second model, the solving modality consists 

in reduction to an optimization problem with a single 

objective function. 

Environmental protection against pollution is 

a priority not only for the European Union but also 

for the countries that wish to joint to EU, countries 

that make efforts for harmonization of the specific 

legislation. The community environmental policy is 

based on its integration within the EU sequential 

policies, paying a special attention to the measures for 

pollution prevention. 

There are numerous concerns related to air, 

water and soil pollution generated by exceeding the 

limit concentrations of different pollutants, around the 

whole world. For pollution reduction there were 

conceived mathematic models by different 

complexities. Most of them refer to air, soil, water, 

air-water, air-soil, soil-water pollution. The main 

types of models are based on differential 

deterministic and stochastic equations (ordinary 

differential equations, equations with partial 

derivates), algebraic static equations, Petri networks, 

mathematic or stochastic programming, optimal 

control theory, Markov chains, Markov processes, 

Monte Carlo simulation and models based on 

mathematic equations (Radulescu, 2002). 

Environmental risk management is a relative new 

term in literature. This refers both to the risk and its 

effects diminishing measures. 

583


It is very important to identify the risk and to 

estimate it in order to be analyzed. The risk analyzing 

process tries to identify all the results of an action. 

The risk estimation is done using the analytic 

methods or simulation. There are estimated thus the 

occurrence probability of every disaster, as well as 

the associated magnitude (dimension). The risk 

analysis process uses technical information related to 

estimations and other additional available 

information, for assessing diverse variants of possible 

actions. An original model based on multiple criteria 

optimization to appropriate financial funds for 

atmospheric pollution reduction is presented. For this 

model, the solving manner is specified by reduction 

to an optimization problem with a single objective 

function (Radulescu, 2002). 

5.1. Measures for calculus of the risk value 

The probability theory offers many adequate 

tools for modeling the risk phenomenon. Any activity 

exhibits an incertitude element. From mathematical 

point of view, the incertitude will be modeled using 

random variables or, more generally, using the 

stochastic processes. The risk that appears within an 

activity may be described with adequate measures. 

One of the most used measures is the dispersion of 

the random variable, which describes the incertitude 

of the respective activity. Another measure of the risk 

is given by the repartition function of the random 

variable. More precisely, if X is a random variable 

that describes the risk associated to a decision, F x is 

the repartition function associated to variable X, and f x 

is the probability density of the random variable X, 

then using Eq. (2): 

+∞ 

∫ 

−∞ 

µ = E(X ) = xdF ( x) 

, (2) 

the risk measures result from Eqs. (3, 4): 

+∞ 

∫ ( 

−∞ 

2 

2 

σ = var( X ) = x − µ ) dF ( x) 

(3) 

+∞ 

1/ 2 

⎤ 

2 

( x − µ ) dFx 

( x) 

⎥ 

−∞ 

⎦ 

⎡ 

σ = ⎢ ∫ 

(4) 

⎣ 

A measure of the risk may be considered also: 

+∞ 

∫ 

−∞ 

| x − µ | dF ( x) 

(first order central moment) (5) 

x 

Stone has shown that all the measures of the 

risks above presented are special cases of some 

families of risks measures. The first measure of the 

risk within the Stone risk measures family that has 

three parameters is defined as (Eqs.2-6): 

x 

q 

( F x ) 

| (k>0 (6) 

∫ 

−∞ 

k 

R S1 (X) = x − p( 

F ) | dF ( x) 

x 

where p\F x ) defines a level of the profit (success) that 

is used for measuring the abatement. 

The positive number k is a measure of the 

relative impact of the small and big abatements. q(F x ) 

is a level a parameter that specifies the abatements 

will be included in the risk measurement. The second 

measure of the risk within Stone family with three 

parameters is defined as k order root from R S1 (X) 

(Eq. 7): 

⎡ 

R S2 (X) = ⎢ 

⎢⎣ 

q( 

Fx 

) 

∫ 

−∞ 

| x − p( 

F 

x 

) | 

k 

x 

1 

k 

⎤ 

⋅dFx 

( x) 

⎥ 

⎥⎦ 

(7) 

One may observe that through proper 

selection of the parameters p(F X ), q{F x ) and k, the 

above presented risk measurement are special cases 

of those from the Stone family of risk measurements. 

For example, if in (l) k = 2 and p(F x ) = (F x ) 

= µ are inserted, the semi-dispersion is obtained as a 

measure of the risk. A more interesting case related to 

risk measures Stone family is the generalized risk 

measure Eq. (8): 

t 

R F1 (X) = 

∫ 

−∞ 

(t - x) α dF x (x) (α > 0), (8) 

proposed by Fishburn, where t is a superior scopelevel 

that is fixed. This measure results from (l) if one 

choose p(F x )=q(F X ) = t. The parameter “a” of 

Fishburn risk measurement R F1 may be interpreted as 

“k” parameter from the measures Stone family (l) in 

this way: it is a risk parameter, which characterizes 

the attitude toward risk. The values α > l describe a 

sensitive risk, while the values α ∈(0. l) describe an 

insensitive risk. 

Another known measure of the risk is 

Shannon entropy (Eq. 9): 

+∞ 

∫ 

−∞ 

fx( x)ln( 

f 

x 

( x)) 

dx 

(9) 

5.2. Probabilistic modeling of pollution 

Mathematic modeling of air pollution is 

done using the theory of stochastic processes. Thus, 

over long periods of time, the pollution degree may 

be described by a multidimensional stochastic 

process: X = (X t ) t ≥ 0 . For t ≥ 0 attached to the 

components of the random vector: X t = (X l,t ; 

X 2,t ...X m,t ) represents the concentrations of the 

atmospheric pollutant factors. Repartition function of 

the stochastic multidimensional process X, F(t,x) = 

584


F xt (x) = P(X 1,t


only recommended but also necessary for engineers, 

particularly for the chemical engineers that analysis 

and manage the risk for taking the optimum decisions 

on safety. 

7. Integrated environmental impact and risk 

assessment 

7.1. Short introduction 

Environmental impacts and risks can be 

assessed applying different method as diagrams, 

check lists, matrix or combined methods (Gavrilescu, 

2003; Macoveanu, 2005). The method to evaluate the 

environmental impact and risk described herein is a 

combination between tow methods: global pollution 

index, matrix of importance scale (Robu, 2005; Robu 

and Macoveanu, 2005b). An algorithm developed as 

software designated as SAB was applied to 

automatically quantify the environmental impacts and 

risks that arise from an evaluated activity, considering 

the measured concentration, levels of quality 

indicators. Also, the new method considered the 

principles of environmental impact from method of 

importance matrix, from which the term importance 

of environmental component and the way of its 

quantification were assumed. 

The environmental evaluation system is 

divided into estimation and quantification of 

environmental impacts in terms of measurable units, 

in this case as environmental importance units (IU). 

The environmental scores obtained in environmental 

impact assessments are basely composed from two 

parameters: the magnitude of environmental impacts 

and the importance. 

The quality (Q) of environmental component 

is quantified as the ration between the maximal 

allowed concentration concordant to national 

legislation and the measured concentration of 

pollutants. If this parameter Q has values close or 

higher than 1, then the environmental component has 

a good quality, if this parameter has values close to 0, 

then the quality of environmental component is very 

poor. The values of quality indicators that are 

considered representative for characterization of 

environmental components in evaluation process have 

to be according with national standards, under the 

maximal allowed concentration. 

When the measured values of quality 

indicators are equal or about with values of alert level 

(70% from maximal allowed concentration), then 

there is certain stress, that could be a possible impact, 

a hazard on quality of environmental component, 

hazard that can become a risk, if no pollution 

prevention measures are taken. 

7.2. Method description 

The fact that the environmental impact 

assessments have a great subjectivity, the 

environmental specialists (Callow, 1998; Macoveanu, 

2005; Robu, 2005) considered that is an acute need to 

use various methods, statistical techniques in order to 

minimize this subjectivity. The method SAB is settled 

up to evaluate the environmental impact and risk, 

considering the main environmental components: 

surface water, ground water, air and soil. To 

characterize the quality of environment, the specific 

quality indicators for each environmental components 

considered in evaluation process, were taken into 

account. It was also considered the specific of 

activity, installation, equipment assessed. 

This new method for integrated 

environmental impact and risk assessment (EIRA) can 

be applied for different activities, various industrial 

installation, processes, industrial sites and other 

related activities which are performed on. 

Considering the following environmental 

components: ground and surface water, soil and air, 

the evaluation of environmental impacts is done using 

a matrix in order to calculate the importance of each 

environmental component, potentially affected by the 

industrial activities. 

The importance parameter can take values 

between 0 and 1; value 1 represents the most 

important environmental component (Goyal and 

Deshpande, 2001). These values are assigned by the 

evaluator to each environmental component. Then, 

the matrix calculates the importance units (IU) for 

ground and surface water, soil and air (Table 1). An 

example is given in Table 2. 

The impact on environmental component 

(EI) directly depends on measured concentration of 

pollutants, and it is expressed as the ratio between 

importance units (IU) and quality of environmental 

component (EQ), defined as follows (Eq. 10): 

IU IU ⋅Cmeasured 

EI = = 

(10) 

Q MAC 

Table 1. The calculation of importance units for 

environmental components 

Environmental 

component 

Surface 

water (l) 

Ground 

water (m) 

Soil 

(n) 

Surface water 0.90 1.13 = 0.95 = 

(l) 

(1/m) (l/n) 

Ground water 0.80 1.00 = 0.84 = 

(m) 

(m/m) (m/l) 

Soil (n) 0.95 1.19 = 1.00 = 

(n/m) (n/n) 

Air (o) 1.00 1.25 = 1.05 = 

(o/m) (o/n) 

l – importance value for surface water, 

m – importance value for ground water, 

n – importance value for soil, 

o – importance value for air 

Air (o) 

0.90 = 

(l/o) 

0.80 = 

(m/o) 

0.95 = 

(n/o) 

1.00 = 

(o/o) 

The parameter quality of environmental 

component (Q) is defined as follows (Eq.11): 

MAC 

Q = (11) 

C measured 

586


where: 

MAC – maximal allowed concentration of quality 

indicators; 

C measured – measured concentration of quality 

indicators. 

Table 2. Importance units obtained by solving the matrix 

from Table 1 

Environmental 

component 

Normalized weights 

Surface water 

(l) 

0.27 = 

1/(0.9+0.8+0.95+1.0) 

Ground water 0.22 = 

(m) 

1/(1.13+1.0+1.19+1.25) 

Soil (n) 0.26 = 

1/(0.95+0.84+1.0+1.05) 

Air (o) 0.27 = 

1/(0.9+0.8+0.95+1.0) 

Importance 

units 

(IU = 

NWx1000) 

273.97 

219.18 

260.27 

273.97 

After the calculation of importance units, the 

next step was to calculate the quality of each 

environmental component defined above. If the 

quality parameter of environmental component is 

equal with 0, it results that the environmental quality 

is very poor (this means that the measured 

concentration of pollutant is very high); if EQ value is 

close to 1, or higher than 1, then the quality of 

environmental component is very good (Goyal and 

Deshpande, 2001). The impact on surface water 

(EIsw) is given by the following equations (Eqs.12- 

14): 

IUsw 

EI sw = (12) 

Q 

EI 

sw 

n 

∑ EI sw i 

i= 

sw = 1 ( ) 

n 

measured i 

(13) 

MACi 

Q ( sw) 

= 

(14) 

i 

C 

EI(sw)i – environmental impact on surface water, 

considering quality indicator i; 

i – quality indicators (e.g. COD-Cr, BOD etc.); 

EQ(sw)i – quality of surface water, considering the 

quality indicator i; 

IUsw – importance units obtained by surface water; 

MAC i – maximal allowed concentration for quality 

indicator i; 

C measured i – measured concentration for quality 

indicator i. 

It can be observed that the global impact on 

environmental component j is the average of the 

impacts considering the quality indicators i. Thus, the 

impact on ground water (EI gw ), air (EI a ) and soil (EI s ) 

are quantified in the same way (Eqs.15-20). 

EI 

n 

∑ EI gw i 

i= 

gw = 1 ( ) 

gw 

n 

(15) 

IU gw 

EI gw = (16) 

Q 

EQ(gw)i – quality of environmental component 

ground water, considering 

the quality indicator i; 

IUgw – importance units obtained by ground water. 

EI 

n 

∑ EI a i 

i= 

a = 1 ( ) 

a 

n 

(17) 

IUa 

EI a = (18) 

Q 

EQ(a)i – quality of environmental component air, 

considering the quality indicator i; 

IUa – importance units obtained by air. 

EI 

n 

∑ EI s i 

i= 

s = 1 ( ) 

s 

n 

(19) 

IUs 

EI s = (20) 

Q 

EQ(s)i – quality of environmental component soil, 

considering the quality indicator i; 

IUs – importance units obtained by soil. 

Table 3. The calculation of probability 

Environm 

comp. 

Surface 

water (l) 

Ground 

water (m) 

Soil (n) 

Surface 0.90 1.13 = (1/m) 0.95 = 

water (l) 

(l/n) 

Ground 0.80 1.00 = (m/m) 0.84 = 

water (m) 

(m/l) 

Soil (n) 0.95 1.19 = (n/m) 1.00 = 

(n/n) 

Air (o) 1.00 1.25 = (o/m) 1.05 = 

(o/n) 

Table 4. The probability units 

Air (o) 

0.90 = 

(l/o) 

0.80 = 

(m/o) 

0.95 = 

(n/o) 

1.00 = 

(o/o) 

Environmental 

Probability units 

component 

Surface water (l) 0.27 = 1/(0.9+0.8+0.95+1.0) 

Ground water (m) 0.22 = 1/(1.13+1.0+1.19+1.25) 

Soil (n) 0.26 = 1/(0.95+0.84+1.0+1.05) 

Air (o) 0.27 = 1/(0.9+0.8+0.95+1.0) 

This way the impacts for each environmental 

component considered representative for the 

evaluated situation were calculated. The next step was 

587


to quantify the risks that arise from the activities 

considered, in the view of the results for 

environmental impacts. The risks are calculated 

follows (Eq.21): 

RM 

j 

= IM 

j 

⋅ Pj 

(21) 

ERj – environmental risk for environmental 

component j; 

EIj – environmental impact on environmental 

component j; 

Pj – probability of occurrence of impact on 

environmental component j. 

The probability of impact occurrence was 

calculated using the same matrix as described above 

(Table 1) to calculate the importance units. The 

normalized weights are presented in Table 4. The 

evaluator has to give values between 0 and 1 for 

probability (Table 3), which is detailed in Table 5 

(Pearce, 1999). 

7.3. Advantages and disadvantages 

The data automatically performed by the 

SAB soft are presented in Table 6, and Fig. 3 present 

environmental impacts and risks. 

It has to be emphasized that if the impact 

and risk have very high values, then the impact 

induced by the considered activities on the 

environment is great and the environmental risks are 

at an unacceptable level (major/catastrophic risks). 

High values for environmental impacts and 

risks underlay the presence of pollutants in 

environment in very high concentrations, because 

impact directly depends on the measured 

concentration of pollutants. Considering the impact 

classification from method of global pollution index, 

a classification of impacts and risks is proposed 

(Table 7). 

This new method has the advantages that it 

is very easy to be used by non environmental experts; 

it calculates the impacts and risks, correlated with 

measured concentrations of quality indicators for 

environmental component, considered representative 

in assessment process; it is not a subjective method 

because the subjectivity is removed applying 

mathematical steps (the developed soft - SAB). 

Also, the lack of experience of evaluator 

doesn’t influence the evaluation results that will 

reflect the real situation from the evaluated site, 

where the industrial activities are performed. 

Table 5. Description of probability 

Probability Description Probability units 

Almost certain Is expected to occur in most circumstances (99%) 0.91-1.0 

Likely Will probably occur in most circumstances (90%) 0.61-0.9 

Possible Might occur at some times (50%) 0.31-0.6 

Unlikely Could occur at some times (10%) 0.05-0.3 

Rare May occur only in exceptional circumstances (1%) 10 µm), mg/mc 0.05 0.28 0.18 1534.25 435.08 

Soil Extractable compounds, mg/kg 2000 10480 0.19 1363.84 407.12 

1 - maximal allowed concentration according to Romanian legislation; 2 – measured concentrations of quality indicators, 3 – environmental quality; 

4 – environmental impact, 5 – environmental risk. 

588


1600.00 

1400.00 

1200.00 

1000.00 

800.00 

600.00 

400.00 

200.00 

0.00 

430.84 

128.61 

177.63 

34.47 

1363.84 

407.12 

1491.68 

Surface water Ground water Soil Air 

Environmental impact 

Environmental risk 

Fig.3. Environmental impacts and risks 

423.01 

Table 7. Classification of environmental impact and risk 

Impact Description 

Scale 

1000 Degraded 

environment, 

not proper for 

life forms 


Risk Description 

Scale 

1000 Catastrophic risks, all 

activities should be 

stopped 

The aim of this work was to present the main 

procedures, methods, models and approaches, 

generally used in environmental risk assessment. 

Thus, the common notion of risk is associated with 

actions or decisions that may have undesired to 

outcome. This implies that the risk-based approaches 

focus on the negative impacts and their prevention. 

Risk assessment places the emphasis on the potential 

negative environmental impacts of an organization’s 

activities and allows the identification of indicators 

that directly reflect its efforts, efficiency and 

effectiveness in reducing or even preventing them. 

The environmental risk is the result of the interactions 

between the human activities and the environment. 

The ecologic risk management that refers to the 

problematic of the risks generated by the past, present 

and future human activities on flora, fauna and 

ecosystems constitutes only a part of the 

environmental risk management. Risk assessment is 

one of the steps of the general risk management 

procedure. 

Risk management is a technique used to 

identify, characterize, quantify, evaluate and reduce 

losses from actions or decisions that may have 

undesired outcomes. The first step of the generic 

procedure involves the risk identification that is the 

systematic identification of all potential actions or 

decisions with undesired consequences that may 

result from the operation of an organization. The next 

step involves the risk assessment, while further steps 

address issues like the evaluation of risks in order to 

determine the organizations ability or willingness to 

tolerate their consequences in view of the associated 

benefits, and the selection and implementation of the 

most preferable approach for the reduction of 

unacceptable risks. 

The problems concerning the work safety 

and health as well as the risk management in 

emergency situation may be significant from the 

environmental risk point of view. The environmental 

risk management provides a formal set of processes 

that constitutes the fundament for environmental 

decision making and support the decision factor in the 

steps of incertitude level minimization. 

Qualitative risk analyses consist in: control 

lists, integral inspections of the industrial units, 

ranking, preliminary hazard analysis (PHA), what if 

method and HAZOP method (hazard operation), 

while quantitative risk analyses, usually are done 

using: hazard analysis (HAZAN), event tree analysis, 

fault tree analysis. In Romania the qualitative and 

quantitative environmental risk assessment is made 

concordant to Ministerial Order no. 184/1997, and 

examines the probability and the severity of the main 

components of an environmental impact. The 

necessity of additional information regarding the risks 

related to the identified pollution or to the pollutant 

activities developed on a site may determine the 

environmental competent authority to request a risk 

assessment with the aim of evaluating the probability 

of harm and of finding the possible prejudiced 

entities. Not every site affected by a certain pollutant 

will exhibit the same risk or will need the same level 

of remediation. 

589


In consequence, the risk assessment involves 

an estimation (including the identification of the 

hazards, the magnitude of the effects and the 

probability of occurrence) and a calculus of the risk 

(including the quantification of the danger importance 

and consequences for humans and/or environment). 

Risk assessment aims at controlling the risks 

produced on a site by identification of: pollutant 

agents or the most important hazards; resources and 

receptors exposed to the risk; mechanisms of risk 

accomplishment; important risks that emerge on the 

site; general measures needed for reduction of the risk 

to an accepted level. The risk depends on the nature 

of impact upon the receptors but also on the 

probability of the occurrence of this impact. 

Identification of the critical factors that influence the 

relationship source-path-receptor involves the 

detailed characterization of the site from physical and 

chemical point of views. 

Also, this paper briefly described a 

quantitative risk analysis for port hydrocarbon 

logistics, proposed by Ronza A. et.al, 2006, which 

consists in the following steps: data collection, 

scenarios identification, frequency estimation, event 

tree analysis, consequences analysis, individual risk 

estimation and the estimation of global risk for 

population. Mathematic models for environmental 

analysis and assessment are described too. The 

modeling of the environmental systems is a very 

difficult problem owing to their complexity, as well 

to the complexity of their interaction with different 

other systems, interaction that is sometimes hard to be 

defined. 

In this paper, two environmental mathematic 

models were described. The first, probabilistic model 

for risk evaluation uses a repartition function for a 

random vector that describes the concentrations of the 

atmospheric pollutant factors. The latter, an 

optimization model is based on multiple criteria, to 

appropriate financial funds for pollution reduction. 

For the second model, the solving modality consists 

in reduction to an optimization problem with a single 

objective function. 

The paper presents some selection and 

probabilistic methods for risk assessment, particularly 

for risks related to the emissions of the pollutants gas 

originated from a source. The sensitive analysis is 

also presented as a key factor that may have a 

significant impact in risk assessment. This example is 

not a very critical one, but in industrial processes 

critical situations exist. The study can offer an 

increased reliability and confidence in prediction of 

the safety states. The enhanced values of the safety 

factor lead to lower values of the risk, some 

approaches as the current one, resulting in minimizing 

the need of excessive safety borders in design and in 

reducing the expensive analytic and experimental 

approaches. 

The method can be used for prediction of the 

limit state in risk or for estimation of fault occurrence 

probability in reliability analysis. These types of 

studies that lead to consistent conclusions regarding 

the functioning of the technological plants are not 

only recommended but also necessary for engineers, 

particularly for the chemical engineers that analysis 

and manage the risk for taking the optimum decisions 

on safety. 

Lately, the trend is to integrate the 

environmental risk principle into impact assessment 

procedure, or to base risk assessment on life cycle 

assessment. Thus, the method SAB, described herein 

is settled up to evaluate the environmental impact and 

risk, considering the main environmental 

components: surface water, ground water, air and 

soil. To characterize the quality of environment, the 

specific quality indicators for each environmental 

components considered in evaluation process, were 

taken into account. It was also considered the specific 

of activity, installation, equipment assessed. This new 

method for integrated environmental impact and risk 

assessment (EIRA) can be applied for different 

activities, various industrial installation, processes, 

industrial sites and other related activities which are 

performed on. Considering the following 

environmental components: ground and surface 

water, soil and air, the evaluation of environmental 

impacts is done using a matrix in order to calculate 

the importance of each environmental component, 

potentially affected by the industrial activities. 

Concordant to this new method, the impact 

on environmental component directly depends on 

pollutants concentration into environment. This way, 

the impacts for each environmental component 

considered representative for the evaluated situation 

were calculated. The next step is the quantification of 

risks that arise from the activities considered, in the 

view of the results for environmental impacts. 

It has to be emphasized that if the impact 

and risk have very high values, then the impact 

induced by the considered activities on the 

environment is great and the environmental risks are 

at an unacceptable level (major/catastrophic risks). 

High values for environmental impacts and risks 

underlay the presence of pollutants in environment in 

very high concentrations, because impact directly 

depends on the measured concentration of pollutants. 

Considering the impact classification from method of 

global pollution index, a classification of impacts and 

risks is proposed. 

This new method has the advantages that it 

is very easy to be used by non environmental experts; 

it calculates the impacts and risks, correlated with 

measured concentrations of quality indicators for 

environmental component, considered representative 

in assessment process; it is not a subjective method 

because the subjectivity is removed applying 

mathematical steps (the developed soft - SAB). Also, 

the lack of experience of evaluator doesn’t influence 

the evaluation results that will reflect the real 

situation from the evaluated site, where the industrial 

activities are performed. 

590



This work was supported by the Program IDEI, 

Grant ID_595, Contract No. 132/2007, in the frame of the 

National Program for Research, Development and 

Innovation II - Ministry of Education and Research, 

Romania. 

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592




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COMPARATIVE STUDY OF SOME ESSENTIAL ELEMENTS IN 

DIFFERENT TYPES OF VEGETABLES AND FRUITS 

Alina Soceanu 1∗ , Simona Dobrinas 1 , Viorica Popescu 1 , Semaghiul Birghila 1 , 

Vasile Magearu 2 

1 Ovidius University of Constanta, Department of Chemistry, 124 Mamaia Blvd, 900527 Constanta, Romania 

2 

Bucharest University, Department of Analytical Chemistry, 4-12 Elisabeta Blvd., 030018, Bucharest, Romania 

Abstract 

Some industry activities in the area of Constanta (Romania) contribute to the polluting of the environment with heavy metals. In 

order to estimate the pollution level and the danger created by this phenomenon, some analyses are required with regard to 

determining the concentration of the pollutant metals in plants samples. The investigated metals were determined by flame atomic 

absorbtion spectrometry in different types of vegetables and fruits, after the chemical mineralization of the sample with a 

Digesdahl device. These levels were compared with those from literature. 

Key words: metals Fe, Mn, Cd, Zn, Cu, FAAS, pollutants vegetables, fruits 


The concentration of heavy metals in the soil 

is an important issue with regards to human health. 

Ingestion of vegetables grown in contaminated soil 

may pose health issues. The accumulation of metals 

varies greatly both between species and cultivars. 

Heavy metals are not readily absorbed by plants. 

Generally, plants translocate larger quantities of 

metals to their leaves than to their fruits or seeds. 

For the determinations of metals in plants 

various techniques were used, such as total reflection 

X-ray fluorescence spectrometry (TXRF) (Varga et 

al., 1999), X-ray fluorescence spectrometry (Psaras 

and Manetas, 2001; Belakova et al., 1998), flame 

atomic absorption spectrometry (Moraghan et al., 

2002; Beebe et al, 2000), inductively coupled plasma 

atomic emission spectrometry (Perronnetk at al., 

2003; Masson, 1999), inductively coupled plasma 

mass spectrometry (Ivanova et al., 2001; Li et al., 

1998). 

Flame atomic absorption spectrometry (FAAS) 

is probably the most widely used technique for 

analyzing a variety of metals in food due to its 

relatively low cost and excellent analytical 

performances. In this study, samples of vegetables 

(bean, pea, carrot, cucumber) and fruits (peach and 

nectarine) produced in the area of Constanta 

(Romania) were analyzed to determine their content 

in Fe, Mn, Cd, Zn and Cu by flame atomic absorption 

spectrometry (FAAS) and compared with those 

obtained by other authors. 


2.1. Reagents and solutions 

All metal stock solutions (1000 mg/L) were 

prepared by dissolving the appropriate amounts of the 

metals or compounds in dilute acids (1:1) and then 

diluting them with deionised water. The working 

solutions were prepared by diluting the stock 

solutions to appropriate volumes. The nitric acid and 

hydrogen peroxide solutions used were of analytical 

grade, purchased from Merck. 

∗ Author to whom all correspondence should be addressed: asoceanu@univ-ovidius.ro

Soceanu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 593-596 

2.2. Sample preparation 

The vegetables and fruits samples produced in 

the area of Constanta (Romania) were collected 

during one year. These samples were stored in Teflon 

vessels at the room temperature in a dark place for 

further analysis. 

A mineralization step is necessary to obtain a 

finally solution suitable for introduction in the 

spectrometer. This step is recommended even for 

liquid or water-soluble foodstuffs, the destruction of 

the organic matter preventing both spectral 

interferences and the accumulation of the residues in 

the burner head and spray chamber. In this context 

analyzed samples were submitted to digestion with 8 

mL HNO 3 and 10 mL H 2 O 2 at 150 o C in a Digesdhal 

device provided by Hach Company. After the 

complete digestion, sample solutions were filtered 

made up to 50 mL with deionized water. Than Fe, 

Mn, Mg and Zn were determined by FAAS in 

air/acetylene flame using an aqueous standard 

calibration curve. Analyses were made in triplicates 

and the mean values are reported. 

A flame atomic absorption spectrometer 

Shimadzu AA6500 was used for the determination of 

five essential elements (Fe, Mn, Cd, Zn and Cu). An 

air-acetylene flame was used for all elements. 

Monoelement hollow cathode lamps were employed 

to measure the elements. The acetylene was of 

99.999% purity at a flow rate 1.8-2.0 L/min. The 

characteristics of metal calibration are presented in 

Table 1. 

Table 1. Characteristics of metal calibration curves 

Metal λ, nm Concentration range 

(ppm) 

Correlation 

coefficient 

Fe 248.3 0.020-4.000 0.9976 

Mn 279.5 0.008-1.600 0.9984 

Cd 228.8 0.008–1.600 0.9999 

Zn 213.9 0.016-0.510 0.9932 

Cu 324.7 0.010–1.200 0.9990 

The accuracy (expressed as standard deviation 

SD and coefficient of variance CV) of the results was 

determined from three replicates of homogenized 

samples, giving a good standard and precision for the 

analytical results of essential elements obtained by 

FAAS. 

3. Result and discussion 

In Tables 2 and 3 the average values of Fe, 

Mn, Zn, Cd and Cu concentrations in vegetable 

samples (mg/kg) are presented. Concentrations of 

iron found in the bulb of carrot (825.51 mg/kg), in 

stem (506.03 mg/kg) and in leaves (1207.18 mg/kg) 

of cucumber were over the allowable maximum limit 

of iron in vegetables namely 425.5 mg/kg (Food 

Standards Programme, 2001). 

It can be observed that iron concentrations are 

higher in the leaves of bean and pea plant 

comparative to the others parts of these plants. Also, 

the content of iron is higher in the bean than in the 

pea. The plants absorb cadmium through their roots 

and leaves, which affect the plant metabolism and 

growth. The highest concentrations of cadmium in 

polluted plants are always reported for the leaves. The 

bean and pea leaves studied here indicate that levels 

of cadmium are lower than those measured by 

Angelova in bean, respectively pea leaves (6.4 mg/kg, 

respectively 1.13 mg/kg) (Angelova et al., 2003). 

They found that the movement and accumulation of 

the heavy metals (Cu, Cd and Zn) in the vegetative 

organs of different cultivated plants differed 

significantly. They also found that the content of 

heavy metals in the leaves was higher comparative to 

the root system. 

This situation is confirmed by the studies of 

Cobb et al., (2000) about the accumulation of 

cadmium, lead, zinc and copper in different 

vegetables, which indicate that each plant can 

accumulate differently heavy metal. Moraghan 

studied the accumulation of iron in beans (Moraghan 

et al, 2002). He determined the influence of lime, Fe 

chelates and type of soil on accumulation of iron in 

bean. In this context, he observed that iron chelates 

could drastically reduce Mn concentration. 

Table 2. Fe and Cd concentrations in vegetables 

Bean 

(Phaseolus 

vulgaris L) 

Sample 

Concentrations (mg/kg) 

Fe 

Cd 

Green pod 50.48±0.0032 1.97±0.0012 

Leaves 217.77±0.0064 3.73±0.0012 

Flower 188.93±0.004 10.71±0.0025 

Bean 38.52±0.0025 3.3±0.0016 

Pod 31.6±0.0011 2.81±0.0006 

Leaves 153.55±0.0021 4.13±0.0025 

Pea 

(Pisum 

sativum L) Pea 41.93±0.003 1.09±0.043 

Carrot 

(Daucus 

carota L) 

Cucumber 

(Cucumis 

sativus L) 

Bulb 825.51±0.0278 3.391±0.0024 

Leaves 249.3±0.0025 5.73±0.0017 

Root 351.23±0.0027 47.03±0.0215 

Stem 506.03±0.0001 61.32±0.0025 

Leaves 1207.18±0.0022

Comparative study of some essential elements in different types of vegetables and fruits 

Tables 4 and 5 present the average values of 

Fe, Mn, Zn, Cd and Cu concentrations in fruit 

samples (mg/kg). 

It can be notice that, while Cu concentration 

was under detection limit in bulb of carrot, in leaves 

of carrot a high concentration of Cu (157.84 mg/kg) 

was detected of which is over the recommendable 

maximum limit (73.3 mg/kg). 

Peach 

(Prunus 

persica) 

Table 4. Fe and Cd concentrations in fruits 

Sample 

Nectarine 

(Prunus 

persica 

var.nucipersica) 


Fe 

Cd 

Stone 46.9565±0.0019 1.0543±0.0026 

Green 49,28±0.0009 0.27±0.0042 

Almost 73.94±0.0012 2.96±0.002 

ripe 

Ripe 92.02±0.0048 5.43±0.0003 

Leaves 193.74±0.0004 31.3±0.0027 

Stone 67.0723±0.0043 0.8336±0.0019 

Green 19.14±0.0001 2.76±0.0001 

Almost 21.09±0.0015 4.72±0.0016 

ripe 

Ripe 38.74±0.0003 5.98±0.0004 

Leaves 180.32±0.0005 16.32±0.0009 

Table 5. Mn, Zn and Cu concentrations in fruits 

Sample 


Mn Zn Cu 

Peach Stone

Soceanu et al. /Environmental Engineering and Management Journal 6 (2007), 6, 593-596 

Concentrations of iron found in the bulb of 

carrot (825.51 mg/kg), in stem (506.03 mg/kg) and in 

leaves (1207.18 mg/kg) of cucumber were over the 

allowable maximum limit of iron in vegetables; of 

425.5 mg/kg. Iron concentrations are higher in leaves 

of bean and pea plant compared with the others parts 

of these plants. 

While Cu concentration was under detection 

limit in bulb of carrot, a high concentration of Cu 

(157.84 mg/kg) was detected in carrot leaves, which 

is over the allowable maximum limit (73.3 mg/kg). 

All the studied samples are under the 

recommendable maximum limit of Mn in vegetables 

(500 mg/kg). 

Iron concentrations found in fruits are in 

higher quantities than the other studied metals. 

The above results show that content of the 

investigated elements in various vegetables depends 

on the organ of the plant, the growing stage and also 

on the level of area pollution. 

References 

Adhikari T., Manna M. C., Singh M. V., Wanjari R. H. , 

(2004), Bioremediation measure to minimize heavy 

metals accumulation in soils and crops irrigated with 

city effluent, Food Agric. and Environ., 2, 266-270. 

Angelova V., Ivanova R., Ivanov K., (2003), Accumulation 

of lead, cadmium and zinc from contaminated soils to 

various plants, 2 nd International Conference on 

Ecological Protection of the Planet Earth. Agriculture 

and Land Use, Sofia, Bulgaria, 5-8 June. 

Beebe S., Gonzalez A.V, Rengifo, (2000), Research on 

trace minerals in the common bean, J. Food Nutr. 

Bull., 21, 387-391. 

Belakova M., Havranek E., Bumbalova A., (1995), Heavy 

metals and some other elements in medicinal plants 

determined by x-ray fluorescence, J. of Radioanal. 

and Nucl. Chem., 201, 431-437. 

Cobb G., Sands K., Waters M., Wixson B., Dorward-King 

E., (2000), Accumulation of heavy metals by 

vegetables grown in mine wastes, Env. Toxic. and 

Chem., 19, 600-607. 

Codex Alimentarius Commission (FAO/WHO) Food 

additives and contaminants.Joint FAO/WHO Food 

Standards Programme 2001, ALINORM 01/12A:1- 

289 

Dobra M., Viman V., (2006), Determination of the 

concentration of heavy metals in soil and plants by 

inductively coupled plasma-atomic emission 

spectrometry, Environmental Engineering and 


Gergen I., Gogoasa I., Dragan S., Moigradean D., 

Harmanescu M., (2006), Heavy metal status in fruits 

and vegetables from a non-poluted area of Romania 

(Banat Country), Proc. of 7 th Int. Symp. Of Romanian 

Academy-Branch Timisoara, Nov. 6-8, Timisoara, 

Romania. 

Ivanova J., Korhammer S., Djingova R., Heidenreich H., 

Markert B., (2001), Determination of lanthanoids and 

some heavy and toxic elements in plant certified 

reference materials by inductively coupled plasma 

mass spectrometry, Spectro. Acta., 56, 3-12. 

Lacatusu R., Voiculescu A., Kovacsovics B., Lungu M., 

Breaban I., Rusu C., Bretan A., (2006), Heavy Metals 

in Soil-Plant System in a City with Non-Ferrous Ores 

Extraction and Processing Industry, The 18th World 

Congress of Soil Science, July 9-15, 2006, 

Philadelphia, USA. 

Li Y.C., Jiang S.J., Chen S.F., (1998), Determination of Ge, 

As, Se, Cd and Pb in plant materials by slurry 

sampling–electrothermal vaporization–inductively 

coupled plasma-mass spectrometry, Anal. Chim. Acta, 

372, 365-372. 

Masson P., (1999), Matrix effects during trace element 

analysis in plant samples by inductively coupled 

plasma atomic emission spectrometry with axial view 

configuration and pneumatic nebulize, Spectro. Acta., 

54, 603-612. 

Moraghan J.T., Padilla J., Etchevers J.D., Grafton K., 

Acosta-Gallegos J.A., (2002), Iron accumulation in 

seed of common bean, Plant and Soil, 246, 175-183. 

Perronnet K., Schwartz C., Morel J., (2003 Distribution of 

cadmium and zinc in the hyperaccumulator Thlaspi 

caerulescens grown on multicontaminated soil, Plant 

and Soil, 249, 19-25. 

Pettersson O., (1976), Heavy-metal ion uptake by plants 

from nutrient solutions with metal ion, plant species 

and growth period variations, Plant and Soil, 45, 445- 

459. 

Pless-Mulloli T., (2001), Pcdd/Pcdf and heavy metals in 

vegetables samples from Newcastle allotments: 

Assessment of the role of ash from the Byker 

incinerator, Byker Ash Vegetable Report, July, 

University of Newcastle upon Tyne. 

Psaras G.K., Manetas Y., (2001), Nickel Localization in 

Seeds of the Metal Hyperaccumulator Thlaspi 

pindicum Hausskn, Annals of botany, 88, 513-516. 

Secer M., Bodur A., Elmaci O.L., Delibacak N., Iqbal N., 

(2002), Trace element and heavy metal concentrations 

in fruits and vegetables of the Gediz River region, Int. 

J. of Water, 2, 196-211. 

Tahvonen R., Kumpulainen J, (1991), Lead and cadmium in 

berries and vegetables on the Finnish market 1987– 

1989, Fresenius Journal Anal Chem., 340, 242-244. 

Varga A., Martinez R., Zaray G., Fodor F., (1999), 

Investigation of effects of cadmium, lead, nickel and 

vanadium contamination on the uptake and transport 

processes in cucumber plants by TXRF spectrometry, 

Spectro. Acta., 54, 1455-1462. 

596




______________________________________________________________________________________________ 

Book review 

CHEMICAL REACTOR DESIGN AND CONTROL 

William L. Luyben 

Wiley-Interscience, A John Wiley&Sons, Inc., Publication, Hoboken, New Jersey, USA 

ISBN: 978-0-470-09770-0, 2007, XVI+419 pages. 

The book Chemical Reactor Design and 

Control is based on the experience of author William 

L. Luyben, who is a professor of chemical 

engineering at Lehigh University, and who has also 

gained rich experience as an engineer with Exxon and 

DuPont. The great variety of chemical reactions leads 

to a great variety of chemical reactors with various 

configurations, operating conditions, sizes. 

As a result of this, the book offers along 8 

chapters a wide spectrum of information concerning 

reactor basics, as well as design and control of CSTR, 

tubular and batch reactors. Several types of heat 

transfer to or from the reactor vessel are presented. 

Chapter 1, Reactor Basics, reviews some 

aspects concerning the fundamentals of kinetics and 

reaction equilibrium (power-law kinetics, 

heterogeneous reaction kinetics, biochemical reaction 

kinetics), together with the effects of temperature on 

rate and equilibruim for different types of reactions, 

particularized through several examples. 

Multiple reactions are also discussed, given 

that they have a major impact on the design of the 

entire process. In order to supress undesirable sidereactions, 

it is often necessary to operate the reactor 

with a low concentration of one of the reactants and 

an excess of other reactants which have to be 

recovered in a separation section and then recycled 

back to the reaction section. Parallel reactions, series 

reactions are analyzed briefly, in order to allow 

further discussions on the possibilities to determine 

the kinetic parameters of the chemical reactions. 

The classical types of reactors are discussed 

in a qualitative way, pointing out the features of a 

batch, continuous stirred-tank reactor (CSTR) and 

plug-flow reactor (PFR), as idealizations of real 

industrial reactors. 

An important feature highlighted in this 

chapter is the that batch and CSTR reactors can be 

cooled or heated in a variety of ways, which accounts 

in part for their superior controllability compared to 

tubular reactors. Many tubular reactors are operated 

adiabatically, because of the problems in providing 

heat transfer. The author also writes about one of the 

most challenging aspects of chemical engineering: the 

problem of scaling up a process unit from a small 

laboratory or pilot plant to a large commercial size, 

the reactors being one of the more difficult systems to 

deal with. 

Chapter 2, Steady-state Design of CSTR 

Systems studies the steady-state design of perfectly 

mixed continuously operating liquid-phase reactors, 

which can provide valuable information which gives 

reasonably reliable indications of how effectively the 

reactor can be dynamically controlled. The contents 

of the chapter include analyses of several important 

types of reactions and the equations describing each 

of these systems. 

Matlab programs are used for hypothetical 

chemical examples, while the commercial software 

Aspen Plus is used for real chemical examples. The 

following types of reactions are analyzed: 

irreversible, single reactant; irreversible, two 

reactants; reversible exothermic reactions; 

consecutive reactions; simultaneous reactions, in a 

single unit or multiple CSTRs (multiple isothermal 

CSTRs in series with single reactions; multiple 

CSTRs in series with different temperatures; multiple 

CSRTs in parallel; multiple CSTRs with reversible 

exothermic reactions). 

Chapter 3, Control of CSTR Systems, deals 

with steady-state designs of a vareity of CSTR 

systems previously discussed in Chapter 2, but with 

additionally including their dyanmics and control. 

There are quantitatively explored the effects of 

reaction types, kinetics, design parameters and heat 

removal schemes on system controllability. The first

Book review/Environmental Engineering and Management Journal 6 (2007), 6, 597-599 

studied system is a CSTR with jacket cooling where a 

first-order irreversible reaction takes place. A nonlinear 

dynamic model of the reactor jacket, with four 

non-linear ordinary differential equations is 

examined. 

Also, the effects of various parameters on a 

linearized version of the system equations are 

investigated. The linear model allows the use of all 

the linear analysis tools available to the process 

control engineering. In order to demonstrate the 

superior dynamic controllability of high-conversion 

and low-temperature designs, the non-linear 

differential equations are numerically integrated. 

Disturbances in feed flow rate temperature controller 

set point, and overall heat transfer coefficient are 

made, and the peak deviations in reactor temperature 

are compared. 

Moreover, the dynamics and control of the 

previously studied reactor column are investigated 

using a non-linear dynamic model of reactor and 

column. Besides, the steady-state design of an autorefrigerated 

reactor system and dynamics and control 

of this process are considered. 

The use of feed manipulation for reactor 

temperature control is considered a control scheme 

which has the potential to achieve the highest possible 

production rate. The simulation of CSTRs is carried 

out with the aid of ASPEN dynamic simulation. 

Chapter 4, Control of Batch Reactors, 

analyzes the batch chemical reactor, widely used by 

chemists in laboratory studies of the chemistry of 

various systems. The surface to volume area is very 

large, thus heat transfer is very good. At the 

beginning of the chemical industry, most commercial 

reactors were batch, as simply large versions of the 

chemists’ laboratory apparatus. Because batch 

reactors have very important inherent kinetic 

advantages for some reaction systems, they continue 

to be fairly widely used, even when production rates 

are high (polymerization, fermentation). Batch 

reactors are also frequently used in situations where 

production rates are low, such as specialty chemicals, 

because they are quite flexible and can be used to 

produce a number of different products under a 

variety of conditions in the same vessel. The design 

and control problems for batch reactors are more 

difficult than for CSTRs, because of the time-varying 

nature of the batch process. The typical design 

problem is to be given a desired annual production 

rate. The system is non-linear and the control system 

must be capable of handling this non-linearity. The 

optimal operation of a batch reactor is with 

irreversible single-reactant reactions. The temperature 

could be increased to its maximum value as quickly 

as possible, which can give the maximum reaction 

rate and therefore the shortest batch time. 

Batch reactors with two reactants can 

operate quite similarly to the previous case. If 

consecutive reactions are conducted in a batch 

reactor, the optimization of the process aims at 

finding the optimal time to stop the batch, and 

determining the optimal temperature. 

The simulation of this type of reactor is also 

performed using ASPEN Plus. Some examples of 

simulation are provided: ethanol batch fermentor, fed 

batch hydrogenation reactor, batch tetramethyl led 

reactor, fed batch reactor with multiple reactions. 

Chapter 5, Steady-State Design of Tubular 

Reactor Systems discusses about the tubular or plug 

flow reactor, which is characterized by the change of 

variables with axial and radial position. The 

fundamental differences between CSTRs and tubular 

reactors are highlighted, and include: the variation in 

properties with axial position down the length of the 

reactor; the dynamic response to disturbances or 

changes in manipulated variables, i.e. while in a 

perfectly mixed CSTR, a change in an input variable 

has an immediate effect on variables in the reactor, in 

a tubular one it takes time for the disturbance to work 

its way through the reactor to the exit; it is 

mechanically very difficult to achieve independent 

heat transfer at various axial positions, because the 

only two variables which can be manipulated are the 

flow rate of the medium and its inlet temperature; the 

feed temperature is a very important design and 

control variable, unlike the CSTR, where the feed 

temperature has little effect; unlike the CSTR, which 

has essentially no pressure drop, a tubular reactor can 

have a very substantial pressure drop, which can be 

important in the gas phase systems with gas recycle. 

Several types of tubular reactor systems are 

analyzed: adiabatic plug flow reactor (PFR), such as 

single adiabatic tubular reactor systems with gas 

recycle, multiple adiabatic tubular reactor with 

interstage cooling, multiple adibatic tubular reactor 

with cold-shot cooling, cooled reactor systems nonadiabatic 

PFR. 

Chapter 6, Control of Tubular Reactor 

Systems, investigates the dynamic controllability of 

PFR. Four flowsheets are provided along with stream 

conditions and equipment sizes. The reactor is 

modeled by three partial differential equations: 

component balances for two components (A and B), 

and an energy balance. The dynamics of the 

momentum balance in the reactor are neglected, 

because they are much faster than the composition 

and temperature dynamics. The mass flow through 

the reactor is assumed to be constant. Results are 

presented for single-stage adiabatic reactor systems, 

multi-stage adiabatic reactor systems with interstage 

cooling, multi-stage adiabatic reactor system with 

cold-shot cooling, cooled reactor systems, cooled 

reactors with hot reaction. 

Additionally, an ASPEN dynamic simulation 

is performed. Also, a very important industrial 

process for the production of methanol for synthesis 

gas is given as an example of ASPEN dynsmics 

simulation of tubular reactor systems. 

Chapter 7, Heat Exchanger/Reactor Systems, 

considers the Feed-effluent heat exchangers (FEHE) 

system in detail, in order to illustrate the inherent 

dynamic problems with using reactor effluent for preheating 

the feed, despite its steady-state economic 

advantages. 

598

Chemical reactor design and control 

Two alternative structures for feed preheating 

are discussed. Both use a feed effluent heat 

exchanger, but one also uses a furnace. 

Dynamic controllability favors the use of 

both a heat exchanger and a furnace. A very effective 

dynamic control could be provided using a 

completely independent pre-heating and cooling 

system on the reactor feed and effluent streams. 

Unfortunately, this arragement could be unfeasible 

because of high energy consumption. All these 

conclusions are drawn after having studied several 

aspects, such as: steady state design of the process, 

linear analysis, non-linear simulation, hot reactions. 

Chapter 8, Control of Special Types of 

Industrial Reactors, analyzes several industrially 

important reactors, which have non-ideal behavior, 

but operate in steady-state mode. The analysis is 

targeted toward fluidized catalytic crackers, gasifiers, 

fired furnaces, kilns, driers, pulp digesters, 

polymerization reactors, biochemical reactors, slurry 

reactors, micro-scale reactors. 

Because chemical reactors transform raw material 

into valuable chemicals, they are the most important 

part of many chemical, biochemical, polymer and 

petroleum processes. They can operate at low or high 

temperatures, in batch, fed batch or continuous mode. 

The book could be very useful to specialists in the 

field of chemical engineering, professionals who 

work with chemical reactors and students in training 

in reactor design, process control and plant design. 


Department of Environmental Engineering and 

Management 


599

600




______________________________________________________________________________________________ 

Book review 

MODELING OF PROCESS INTENSIFICATION 

Frerich J. Keil (Ed.) 

WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany 

ISBN: 978-3-527-31143-9, 2007, XV+405 pags. 

The integration of several unit operations 

into one single unit is of a major importance in 

chemical process engineering, since it leads to a 

significant reduction of both investment and 

operational costs. Besides, the application of new 

modelling approaches can significantly enhance the 

efficiency of such integration processes. So, 

combining the knowledge involved in process 

engineering and process modelling, this is the first 

book reviewing recent developments in modelling 

methods applicable to process intensification. 

Experts in various areas of process 

intensification, from both industry and academia, 

have contributed to this book that does not cover all 

the developments in this field, but it demonstrates the 

activities in modelling for some representative 

problems. Modeling of Process Intensification edited 

by F.J. Keil However emphasizes the necessity for 

new modelling approaches of new microreactors, 

membrane reactors, ultrasound reactors, and those in 

simulated moving-bed chromatography, magnetic 

fields in multiphase processes or reactive distillation, 

non-stationary processes, and the use of supercritical 

media. 

Frerich J. Keil is a Professor of Chemical 

Reaction Engineering at the Hamburg University of 

Technology. For twenty-two years he has been 

employed at UHDE GmbH in Dortmund working on 

process development of coal gasification, heavy 

water, methanol synthesis, and ammonia synthesis. 

He gained his PhD at the Karlsuhe University of 

Technology in 1976, and is the holder of an honorary 

doctorate from the University of Chemical 

Technology and Metallurgy in Sofia. His research 

interests are diffusion/reaction phenomena in 

catalysis, process modeling, and molecular modeling. 

Professor Keil is the co-editor of several international 

journals and some books, and has published around 

150 research articles. 

The book is structured in eleven chapters. 

After an introduction and overview, in Chapter 2 the 

efforts on process intensification are described from 

an industrial point of view. A special feature is the 

use of molecular simulations on various levels, like 

quantum chemistry, and classical molecular dynamics 

or Monte Carlo simulations. Cash flow analysis and 

project valuation under risk are investigated by Monte 

Carlo approaches. 

Chapter 3 describes flow distributions and 

heat transfer in various microchannels. Fast mass 

transfer and mixing are key aspects of microreactors. 

Modeling of micromixers is discussed in detail. 

Chapter 4 is on modeling and simulation of 

unsteady-state operated trickle-flow reactors. A 

review of unsteady-state operated trickle-flow 

reactors is presented and a dynamic reactor model 

based on an extended axial dispersion model is 

described in detail. 

Chapter 5 consists in an extensive review of 

packed-bed membrane reactors. Computational 

results based on realistic data originating from the 

important class of partial oxidation reactions are 

presented. Results of a three-dimensional model using 

the lattice Boltzmann method are also presented. 

In Chapter 6 are discussed the advantages 

and disadvantages of using segmented flow in microchannels 

to intensify catalytic processes. 

Chapter 7 focuses on chemical-reaction 

modeling in supercritical fluids, in particular in 

supercritical water. This chapter gives detailed 

presentations of modeling of systems by elementary 

reactions and their reaction engineering. 

Chapter 8 consists of two parts: the first one 

explains some fundamentals of cavitation and its 

modeling applied to a so-called “High Energy 

Density Crevice Reactor”, while the second one 

stresses important factors for efficient scale-up of 

cavitational reactors and subsequent industrial


applications based on the theoretical and experimental 

analysis of the net cavitational effects. 

Chapter 9 reviews the applications and 

modeling of simulated moving-bed chromatography 

that represents a powerful purification process 

allowing the continuous separation of a feed mixture 

into two product streams. 

Chapter 10 reviews modeling of reactive 

distillation. The theoretical description is illustrated 

by several case studies and supported by the results of 

laboratory, pilot and industrial scale experimental 

investigations. An outlook on future research 

requirements is given. 

In Chapter 11 are presented experimental 

and theoretical investigations on artificial gravity 

generated by strong gradient magnetic fields that 

could potentially open up attractive applications, 

especially in multiphase catalytic systems where a 

number of factors can be optimized in an original 

manner for improving process efficiency. 

In its treatment of hot topics of 

multidisciplinary interest, this book is of great value 

to researchers and engineers alike. 

Stelian Petrescu 

Department of Chemical Engineering 


602




______________________________________________________________________________________________ 

Book review 

ULLMANN’S 

Modeling and Simulation 

WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany 

ISBN: 978-3-527-31605-2, 2007, XVIII+451 pags. 

The book Ullmann’s - Modeling and 

Simulation, published in 2007 by Wiley-VCH, is a 

handbook which includes contributions given by 16 

authors, on several subjects concerning mathematical 

methods in model design and analysis applied in 

chemical engineering. The main covered topics are: 

- mathematics in chemical engineering; 

- model reactors and their design equations; 

- mathematical modeling; 

- molecular modeling; 

- molecular dynamics simulation; 

- computational fluid dynamics; 

- design of experiments; 

- microreactors- modeling and simulation. 

Frequently encountered problems in 

engineering such as solving systems of linear or nonlinear 

algebraic equations, handling functions of 

complex variables, types of ordinary and partial 

differential equations, integral equations, function 

approximation and function integration, along with 

the principal mathematical results concerning these 

topics are presented in a synopsis in the first part of 

the book. The principles of analytical and numerical 

methods used in solving these problems are outlined. 

The finite difference method, the finite element 

method and the boundary element methods, widely 

used in solving partial differential equations (PDE’s), 

as well as numerical methods for solving integral 

equations, are briefly discussed. Finally, part I 

(authors: B. Finlayson, L. Biegler, I. Grossmann) 

discusses optimization methods and elements of 

probability and statistics. 

The second part of the book (authors: V. 

Hlavacek, J. Puszynski, H. Viljoen, J. Gatica) 

presents models of the principal types of reactors used 

in industrial applications and problems connected to 

this topic. Batch reactors (involving both 

homogeneous and non-homogeneous systems), 

continuous stirred-tank reactors and packed-bed 

reactors are discussed. The physical quantities and 

laws concerning reactors, such as: 

- mass and energy balances; 

- definition of reactor parameters: average bed 

porosity, effective transport coefficients, 

wall heat transfer coefficient; 

- thermo-mechanical effects in the reaction 

system 

are introduced and discussed. Modern topics, such as 

numerical simulation and optimization of chemical 

reactors, are also included. Some examples 

concerning the optimization of batch systems, of 

continuous systems, of multibed adiabatic reactors 

with heat exchange between catalytic stages, are 

presented. 

Part III of the book (author H. Bockhorn) 

presents the principles of mathematical modeling with 

applications to industrial chemistry and chemical 

engineering. The construction and classification of 

mathematical models are introduced. Further on, 

models based on transport equations for probability 

density functions are discussed, with emphasis on 

transport equations for single-point probability 

density functions. Special attention is given to models 

based on the laws governing the physicochemical 

processes (transport phenomena) such as the 

conservation of momentum, enthalpy and mass. 

The fourth part (author D. Boyd) presents a 

short survey of the main trends in molecular 

modeling: conformal modeling, quantum mechanical 

modeling, force field modeling, and statistical 

modeling. 

In the chapter Molecular Dynamics 

Simulation (authors P. Bopp, J. Buhn, M. Hampe) the 

types of interaction models (at intramolecular or 

intermolecular level) are discussed, based on classical 

Boltzmann statistical thermodynamics.


Part VI, Computational Fluid Dynamics 

(author A. Paschedag), presents the principal types of 

partial differential equations describing transport 

phenomena (the continuity equation, the equation of 

motion, Navier-Stokes equation, concentration 

equation, energy equation) and their associated initial 

and boundary conditions. Transport in multiphase 

systems or in systems with turbulent flow is 

considered. The finite volume method used for 

solving the aforementioned PDE equations is briefly 

presented. 

The next chapter Design of experiments 

(authors S. Soravia, A. Orth) presents the basic 

principles for conducting experimental investigations 

and discusses the factorial designs, response surface 

designs and optimal designs. 

Finally, the chapter Microreactors - 

Modeling and Simulation (author S. Hardt) discusses 

flow distributions and heat transfer in straight and 

curved channel geometries, micro-heat exchangers, 

mass transfer and chemical kinetics in microreactors. 

Each chapter has an up-to-date well 

documented list of references. Practical examples are 

discussed and the mathematical, technical or 

computational solutions are outlined in a ready to use 

manner. 

The book contains many illustrations (some 

in color) which make the text more comprehensible. 

In conclusion, the book Ulmann’s – 

Modeling and Simulation, published by Wiley – VCH 

in 2007, could be recommended to specialists in the 

field of chemical engineering, working in industry or 

universities, under or postgraduate students, PhD 

students and all those interested in topics concerning 

mathematical modeling in chemical reaction 

engineering and in transport phenomena. 

Stelian Petrescu 

Department of Chemical Engineering 


604




______________________________________________________________________________________________ 

Book review 

MICRO INSTRUMENTATION 

For high throughput experimentation and 

process intensification – a tool for PAT 

K. M. VandenBussche and R.W. Chrisman (Eds) 

WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim, Germany 

ISBN: 978-3-527-31425-6, 2007, XXIII+495 pags. 

Microinstrumentation is o book managed by 

a team of editors: 

Melvin V. Koch is director of the Center for 

Process Analytical Chemistry (CPAC) and Affiliate 

Professor of Chemical Engineering at the University 

of Washington in Seattle. 

Kurt M. VandenBussche currently manages the 

development of UOP’s exploratory platform 

technologies. 

Ray W. Chrisman is president of Atodyne 

Technologies and a visiting scholar at CPAC. 

The book reveals the interest in process 

intensification and capital and operating costs 

diminishing by miniaturization approaches, which 

have resulted in the application of microinstrumentation 

to the areas of process development 

and process optimization. 

The work includes contribution of many 

authors of universities and research bodies from USA, 

Germany and UK. 

In the first part Introducing the Concepts, 

some aspects concerning analytical tools for use in 

Process Analytical Technology (PAT) as well as the 

topics covered by the Center for Process Analytical 

Chemistry and Summer Institute are first presented in 

“Introduction”. 

This part of the book is organized in four 

chapters. 

Chapter 2 Macro to Micro… The Evolution of 

Process Analytical Systems authors Wayne W. Blaser 

and Ray W. Chrisman, discusses about the correlation 

between analytical instruments and chemical process: 

past technology innovation has had a relevant impact 

on the evolution of process analytical 

instrumentation, and new development in the microinstrumentation 

area are expected to influence the 

growth in the field. 

A general overview of the current state of 

analytical instruments and analytical techniques (gas 

and liquid chromatography, spectroscopy and 

spectrometry, microflow) is carried out. 

Chapter 3, Process Intensification, written by 

Kurt M. VandenBussche introduces the concept of 

process intensification, giving also some relevant 

examples from industry. 

The author defines process intensification in a 

broad sense as “a series of methodologies aimed at 

reducing the capital cost associated with chemical 

processing by removing existing limitation”. Also, he 

analyses the fields of the process intensification, 

reaction engineering, gas-phase mass transfer, liquidliquid 

mass transfer (mixing and emulsions), gasliquid 

mass transfer, mass transfer and gas-solid 

systems, heat transfer. 

The author concluded that the use of 

miniaturization of equipment can lead to an increase 

of heat and mass transfer coefficient by several orders 

of magnitude. 

Two case studies illustrate the impact of 

process intensification (distributed production of 

methanol and distributed production of hydrogen) 

looking somewhat ahead to a scenario of multiple 

energy sources. 

Chapter 4, High Throughput Research, author 

Ray Chrisman explores the lessons learned in the 

early stages of high throughput research for process 

development, discussing how micro-instrumentation 

makes this concept much more reasonable, but also 

exhibiting the current barriers and limitations. 

Some concrete aspects are examined: concept 

of research process, continuous operation and on-line 

analysis, extracting information from processes, 

process development, microreactors for process 

development, microscale reaction characterization.

Book review /Environmental Engineering and Management Journal 6 (2007), 6, 605-607 

Part II, Technology Development and Case 

Studies, is structured on 11 chapters, being the most 

consistent part of the book. It includes studies on the 

ways to combine effective sampling and sample 

conditioning with monitoring tools, as elegant means 

of gathering intrinsic data within microtechnology, 

combined with proper resources, which could provide 

direct access to the underlying mechanisms and 

kinetics of various steps of a certain chemical 

process. Some examples are provided, which show 

recent developments and achievements of 

microtechnology systems for studying and controlling 

chemical reactions. 

Chapter 6, Microreactor Concepts and 

Processing, authors: Volker Hessel, Partick Löb, 

Holger Löwe, Gunther Kolb introduces and analyses 

microreactors as a milestone in getting the technology 

accepted. Also, microreaction technology is 

considered to deliver novel innovative tools for the 

chemical processing industry. 

Some microstructured systems are examined 

such as: microstructured mixer-reactors for pilot and 

production range and scale-out, caterpillar 

microstructured mixer-reactors, microstructured heat 

exchanger-reactors, fine-chemical microreactor 

plants. Also, process development issues are 

highlighted for industrial production of fine 

chemicals. 

Microreactor laboratory-scale process 

developments are approached in relation with future 

industrial use. Also, future directions are revealed 

considering the potential of microreactors for organic 

reactions, because they would make possible the 

overcome of some limitation (mainly kinetic). The 

conclusion is that microsystems technology 

advantages, most pronounced at the laboratory scale 

have to be supplemented by competences in plant and 

process engineering. 

Chapter 7, Non-reactor Micro-component 

Development, authors: Daniel R. Palo, Victoria S. 

Stenkamp, Jamie D. Holladay, Paul H. Humble, 

Robert A. Dagle, Kriston P. Brooks, reviews research 

and development activities related to non-reactive 

applications of microchannel-process technology, 

covering heat transfer, mixing, emulsification, phase 

separation, phase transfer, biological process, body 

force applications. Ongoing activities in microchannel 

process technology development from single channel 

laboratory experiments to industrially-driven, 

multichannel and multi-unit development are 

overviewed. 

Research results on some chemical unit 

operations are presented: heat transfer, mixing, 

emulsification, phase separation, phase transfer, but 

also results concerning biological processes are 

evaluated. The conclusion is that microchannel 

process technology has broad application, even in 

non-reactive systems. 

Chapter 8, Microcomponent Flow 

Characterization, written by a large group of authors, 

outlines correlations and pertinent theoretical 

concepts for slow velocity flow and diffusion: 

pressure drop, entry length, mixing due to connection 

and diffusion. The work is conducted using 

computational fluid dynamic approach (CFD) assisted 

by the program Comsol Multiphysics. 

Engineering correlations are presented and 

analyzed for pressure drop and entry length by 

considering the common geometrical flow channels 

and laminar flow. Mixing is also studied in laminar 

and turbulent flow regimes, even when there are flow 

and concentration variations. The importance of flow 

and diffusion characterization using CFD is illustrated 

in relation with a reaction system. 

Chapter 9, Selected Development in Microanalytical 

Technology describes various technologies 

that exemplify improvements in analytical field for 

achieving faster analytical response, when minimized 

components are involved, selected from the 

technologies developed and studied at CPAC. These 

developments include: mixing efficiency, cleaning 

validation, particles sizing, chemical composition, 

coating characterization, vapor characterization, 

viscosity/rheometrics, moisture, bio-assay. 

The analysis refers to: application of on-line 

Raman spectroscopy to characterize and optimize a 

continuous microreactor, developments in ultra micro 

gas analyzers, nuclear magnetic resonance 

stereoscopy, surface plasmon resonance (SPR) 

sensors, dielectric spectroscopy, liquid-phase 

microseparation devices in process analytical 

technology, grating light reflection spectroscopy. 

Chapter 10, New Platform for Sampling and 

Sensor Initiative (NeSSI), written by David J. 

Welthkamp, describes a new type of fluidic system 

developed by the Chemical and Petro-chemical 

Industries for process analyzers and related samples 

handling systems, under the aegidis of NeSSI TM (New 

Sampling/Sensor Initiative), which is largely 

presented in the chapter body. 

Some details are given about the philosophy 

and commercial implementation of new sampling 

systems developed under NeSSI TM program. 

Chapter 11, Catalyst Characterization and 

Gas Phase Processes, authors Michelle J. Cohn and 

Douglas B. Galloway, details some of the tools for 

kinetics reactivity and diffusion characterization that 

help to provide a better understanding of catalytic 

processes and to improve the rate of process 

development. 

Chapter 12, Integrated Microreactor System 

for Gas Phase Reactions, authors David J. Quiram et 

al., discusses the context developed by 

microfabrication technology that provides a platform 

for invention of highly instrumented microscale 

reactor systems, which incorporate new innovative 

analytical capabilities, allow point-of-use synthesis 

and small-scale manufacturing, implementation of 

novel high-throughput screening methods. 

Chapter 13, Liquid Phase Process 

Characterization, authors Daniel A. Hickman and 

Daniel D. Sobeck, deals with the issues of 

development of a system devoted to the 

characterization of homogeneous liquid phase 

606

Micro Instrumentation 

reactions using serial screening in a tubular reactor. 

The studied system uses a single microchannel 

reactor with reactants injected as finite pulses. In 

order to design or select the system components to 

enable analysis of the reactor effluents at undiluted, 

steady-state concentrations while injecting only 

microliters of reactant solutions per experiment, 

fundamental reactor engineering principles (equation 

and constraints for heat transfer, mixing, axial 

dispersion, pressure drop are considered. Also, 

experimental data that validate the behavior of the 

reactants are provided. 

The tubular reactor was chosen for the study of 

low axial dispersion of injected reactants, in order to 

analyze axial dispersion of Newtonian fluids in 

circular tubes. 

Chapter 14, Novel Systems for New 

Chemistry Exploration, author Paul Watts, evidences 

the performance of microreactors – as a network of 

micron-sized channels etched into a solid substrate, 

applied in pharmaceutical industry and fine chemicals 

synthesis. 

Some chemical synthesis in microreactors are 

described (synthesis of pyrazoles, peptides) as well as 

reaction optimization, stereochemistry. Chemical 

synthesis in flow reactors is approached in relation 

with compounds purification. The conclusion is that 

reactions performed in microreactors generate 

relatively pure products in high yield, in comparison 

with equivalent bulk reactions, and in much shorter 

time. A very important feature is that the reactants 

and products are separated in real time, so that rapid 

screening is facilitated. 

Chapter 15, Going from Laboratory to Plant to 

Production using Microreactors, authors: Michael 

Grund , Michael Harbel, Dick Schmaez, Hanns 

Wurziger discusses about the unique property of 

miniaturized reaction systems in the context of 

production in the multikilogram up to tone scale. 

Case studies concerning the application of 

microreaction technology at Merck KGaA are 

presented, that include: nitration, microreaction 

system “MICROTAUROS”, automated reaction 

optimization, upscale in larger laboratory scale, 

upscale in pilot plants. 

The fact that the continuous initiation occurs in 

a reaction volume diminished by about two orders of 

magnitude markedly increases the inherent safety, as 

well as the conversion and selectivity. 

Part III, A Summary and Path Forward 

contains concluding Remarks drawn by Melvin V. 

Koch, Ray W. Chrisman and Kurt M. 

VanderBussche. A summary of the work is provided, 

together with the path forward. 

References are given throughout the book 

including basic works as well as papers on the new 

research and development in the field. 

The book written in very modern manner is 

very useful for chemical and process engineers, 

chemists, analytical chemists, materials scientists, 

chemical equipment engineers, specialists in 

pharmaceutical and fine chemical synthesis. 


Camelia Beţianu 

Florentina Anca Căliman 




607

608

Environmental 

Engineering 


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