Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Mercury (II) removal from Aqueous Solution by Using Modified Ordered Mesoporous Carbon
Nuran Böke 1,2 , Ziboneni Godongwana 1 , Leslie Petrik 1 *
1 Department of Chemistry, University of the Western Cape, Cape Town 7535, South Africa
2 Department of Chemical Engineering, Ege University 35100, Turkey
Abstract- Modified mesoporous carbon (MOMC) was applied to remove Hg (II) from contaminated model aqueous solutions. Batch adsorption
experiments were carried out to evaluate the adsorption behaviour of Hg (II) onto MOMC. The Langmuir adsorption model fitted to the
experimental data with a regression coefficient of R 2 =0.9796.
Ordered mesoporous carbons (OMC) exhibit both well –
ordered mesoporosity and graphitic character. Because of their
regular pore size and pore shape and also large surface area,
these materials have great potential in environmental
processes. But in some processes, such as adsorption, the
material must have some additional specifications such as
binding sites. In this study we prepared an modified OMC
(MOMC) which has functional groups for Hg (II) b inding and
used it in adsorption of Hg (II) from model contaminated
aqueous solutions.
In the first stage of the work SBA-15 was synthesized by
using a triblock copolymer (P123) [1]. OMC materials have
been synthesized using SBA-15 as ordered mesoporous silica
template. Chemical vapour deposition (CVD) was applied
using liquid petroleum gas (LPG) as the carbon source as a
rapid and simple route to prepare OMC [2]. LPG infiltrated
the mesoporous silica template, and thermally decomposed to
form a structurally robust, ordered mesoporous carbon
material analogous to SBA-15 after removal of the silica
template.
In an effort to enhance mercury removal from the aqueous
solution, OMC was modified by a combined treatment of
nitric acid and (3-mercaptopropyl) triethoxysilane to introduce
sulphur containing functional groups into the structure of
mesoporous carbon [3].
Batch adsorption test were done for adsorption of
mercury(II) onto MOMC. 10 mg adsorbent and 50 mL of
Hg(II) solution with the desired concentration at pH=5.5
placed into the capped flasks [4]. Duplicates for each
concentration were placed in a shaker at 25 o C.
After a predetermined time of shaking the solid adsorbent
and liquid were separated by filtration through a filter paper.
Filtered solutions collected in capped bottles. These solutions
were diluted in 100 mL volumetric flasks to adjust the
concentrations of them into the measurement range of the
UV/VIS spectrophotometer. For measuring Hg(II)
concentration of the samples and standard solutions the
method given by Ramakirishna et al. was followed [5]. In this
method Hg(II) is determined as ternary complex with
rhodamine 6G and iodide.
The adsorption isotherm of Hg(II) removal by MOMC is
shown in Figure 1 as dots.
The Langmuir isotherm model was applied to analyze the
adsorption equilibriu m of Hg (II) on M OMC[6].
and rate of adsorption, respectively. The linear plot of C e /Q e
versus C e showed that the adsorption follows the Langmuir
isotherm model for Hg (II) adsorption. The values of Q o and b
were calculated from the slope and intercept of the plot, and
the values obtained were Q o =250 mg/g and b=0.0386 L/mg,
respectively. Using Q o and b values the Langmuir isotherm
was obtained. The Langmuir isotherm can be seen in Fig. 1 as
a continuous curve.
Figure 1. Adsorption isotherms of Hg(II) removal by MOMC. Ce :
equilibrium Hg(II) concentration, Qe: amount of Hg(II) adsorbed at
equilibr ium time
In summary, adsorption of Hg (II) could be described by
Langmuir model, (regression coefficient R 2 =0.9796). The
Langmuir isotherm constants were found as Q o =250 mg/g and
b=0.0386 L/mg, respectively.
*Corresponding author: 1Tlpetrik@uwc.ac.za
[1] J. Parmentier et al., J Phys. and Chem. of Solids 65 139–146
(2004).
[2] P. Ndungu et al., Microporous and Mesoporous Materials 116
593–600 (2008).
[3] A. Walcarius, Analytica Chim. Acta 508 87–98(2004).
[4] Chemosphere 52 835–841 (2003).
[5] T.V. Ramakirishna et al., Anal. Chim. Acta 84 369-375 (1976).
[6] K. Kadirvelu et al., Carbon 42 745–752 (2004).
C e /Q e = C e /Q o + (1/b* Q o )
[1]
where, C e is the equilibriu m concentration (mg/L) and Q e is
the amount of Hg(II) adsorbed (mg/g) at equilibriu m time. Qo
and b are Langmuir constants related to adsorption capacity
6th Nanoscience and Nanotechnology Conference, zmir, 2010 340