Heavy metal adsorption on iron oxide and iron oxide-coated silica ...

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Table 2.1 Extraction Methods for OxidesMethod Extractants Target forms of iron oxides ReferencesDithionite-citratemethodAcid ammoniumoxalate methodHydroxylaminemethodTiron methodPyrophosphate‘methodCitrate-ascorbatemethodSodium hydrosulfite (Na2S2O4)Sodium citrate (Na3C6HSO7•2H2O)Ammonium oxalate ((NH4)2C2O4-1-12O)Oxalic Acid (H2C2O4.2H2O)Hydroxylamine hydrochloride(NH2OH•HC1)-hydrochloric acid (HC1)4, 5-dihydroxy-1, 3-benzene-disulfonicacidSodium pyrophosphate (Na4P2O 7-2H2O)Sodium citrate (Na3C6H5O7)Sodium ascorbateCrystalline, amorphous, and organiccomplexedFe, Mn, and AlAmorphous and organic-complexedFe, Mn, and AlAmorphous and organic-complexedFe and AlAmorphous and organic-complexedFe and AlOrganic-complexed Fe and AlAmorphous FeRoss and Wang(1993)Ross and Wang(1993)Ross and Wang(1993)Ross and Wang(1993)Ross and Wang(1993)Reyes and Torrent(1997)EDTA method Ethylenediaminetetraacetic acid (EDTA) Amorphous Fe Borggaard (1981)Ti(III)-citrate-EDTA-HCO3methodAscorbic acidoxalatemethodTitanium (III) chloride (TiC13)Sodium citrate dehydrate ((Na3C6HSO7)Tetrasodium EDTA (Na4EDTA)Sodium bicarbonate (NaHCO3)Ascorbic acid (C6H8O6)Ammonium oxalate ((NH4)2C2O4•H2O)Crystalline and amorphous FeRyan andGschwend(1991)Crystalline Fe Shuman (1982)
11oxides. Because extraction methods suggest the mineral form, dissolution data arecommonly used for soil classification.In this study, dithionite citrate will be used for extracting both crystalline andamorphous Fe oxide, and hydroxylamine will be employed for amorphous Fe oxide. Theamount of crystalline Fe oxide is therefore the difference between the two.2.1.4 Coating FactorsThe amount of coating may be influenced by factors such as coating temperature, particlesize, surface area, roughness, and other characteristics of the supporting media. Wang(1995) applied 0.04 g Fe g -1 GAC and Fan (1996) applied 0.055 g Mn g -1 GAC in theirstudies to achieve higher coating efficiencies. Metal concentrations initially applied bymany researchers (Edwards and Benjamin, 1989; Stahl and James, 1991a, b; Wang, 1995;Fan, 1996; Khaodhiar et al. 2000; Kuan et al. 1998; Joshi and Chaudhuri, 1996;Stenkamp and Benjamin, 1994; Bailey et al. 1992) are usually in the order of 10-3 to 10-2g <strong>metal</strong> g-1 media. A <strong>metal</strong> concentration of 0.05 g Fe g -1 silica will be applied in thisresearch.One important variable affecting the degree of coating is temperature. Fan (1996)obtained more Mn oxide coatings on granular activated carbon (GAC) at 160 °C than 105°C, although the same concentration of Mn was applied. Edwards and Benjamin (1989)found that as Fe dose increased a much greater percentage of the surface was coveredupon heating (110 ± 10 °C) as opposed to precipitation without heating. Also, thecoatings produced with heating were observed to be more resistant to abrasion andexposure to mild acid solutions than those produced through alkaline precipitation (noheating). However, from their study it is not clear whether a difference in detachment
Page 1 and 2: Copyright Warning & RestrictionsThe
Page 3 and 4: ABSTRACTHEAVY METAL ADSORPTION ON I
Page 5 and 6: HEAVY METAL ADSORPTION ON IRON OXID
Page 7 and 8: APPROVAL PAGEHEAVY METAL ADSORPTION
Page 9 and 10: Fan, M.; Boonfueng, T.; Xu, Y.; Axe
Page 11 and 12: ACKNOWLEDGMENTI would like to expre
Page 13 and 14: TABLE OF CONTENTS(Continued)Chapter
Page 15 and 16: TABLE OF CONTENTS(Continued)Chapter
Page 17 and 18: LIST OF TABLES(Continued)TablePageB
Page 19 and 20: LIST OF FIGURES(Continued)FigurePag
Page 21 and 22: LIST OF FIGURES(Continued)FigurePag
Page 23 and 24: CHAPTER 1INTRODUCTIONHeavy<
Page 25 and 26: 3and Sigg, 1992; Gunneriusson et al
Page 27 and 28: CHAPTER 2OXIDES AND THEIR EFFECT ON
Page 29 and 30: 7et al. 1996; Green-Pedersen et al.
Page 31: 9identify components, distribution,
Page 35 and 36: 13Table 2.2 Some Coating Work and C
Page 37 and 38: 15increasing the sorbate concentrat
Page 39 and 40: 17mole Cu g-1 goethite (-1-7% of th
Page 41 and 42: 19Overall, macroscopic adso
Page 43 and 44: 21hematite (up to 9.9 limo' Pb ril-
Page 45 and 46: 23concentration in their system was
Page 47 and 48: 25Surface complexation modeling (SC
Page 49 and 50: 27Overall, surface complexation mod
Page 51 and 52: 29Spectroscopic techniques, especia
Page 53 and 54: 31• Understand the effect of comp
Page 55 and 56: 33existing in almost all soils and
Page 57 and 58: CHAPTER 4EXPERIMENTAL METHODSIn thi
Page 59 and 60: 37included coating temperature (T),
Page 61 and 62: 39generated at 45 kV and 40 mA, sca
Page 63 and 64: 41PZC include electrophoretic mobil
Page 65 and 66: 43Lin-edge, from 8,133 to 8,884 eV
Page 67 and 68: CHAPTER 5CHARACTERIZATION OF IRON O
Page 69 and 70: 47measured by potentiometric titrat
Page 71 and 72: Table 5.2 XRD Data of Alfa Aesar (A
Page 73 and 74: 51Table 5.3 XRF Results for Alfa Ae
Page 75 and 76: Figure 5.4 Particle size distributi
Page 77: 55Figure 5.5 ESEM micrograph for Al
Page 80 and 81: 585.2.5 Surface Charge Distribution
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Figure 5.10 Potentiometric titratio
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CHAPTER 6SYNTHESIS AND CHARACTERIZA
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Figure 6.1 Comparison between Fecon
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Figure 6.2 XRD patterns for goethit
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68iron oxide coatings at 60 °C, go
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70substrate diameter of 0.2 mm, an
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72goethite and silica results in on
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Figure 6.7 ESEM micrograph (9000x)
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76Furthermore, because discrete goe
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78Table 6.2 Surface Area and Porosi
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Figure 6.10 Surface charge distribu
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Figure 6.11 Ni adsorption</
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84that for pure silica, and the goe
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Table 7.1 Sample Preparation Condit
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Figure 7.2 EXAFS spectra of Pb/HFO
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Figure 7.3 Fourier transform and fi
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Figure 7.4 Fourier transform and fi
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Table 7.3 EXAFS Results of Pb/HFO S
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967.2 Fe XAS of Iron Oxides and Pb/
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Figure 7.7 EXAFS spectra of iron ox
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100and Venturelli, 1999). Overall t
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102(hematite, goethite, akaganeite,
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104adsorption proc
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106of pH, ionic strength, Pb loadin
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Figure 8.1 Ni adsorption</s
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110high metal load
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Figure 8.3 x(k)•k3 spectra and Fo
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Figure 8.4 (k)•k3 spectra of Ni-H
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Figure 8.5 Fourier transforms (magn
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118be fit using either Fe or Ni ato
Page 142 and 143:
1208.3 EXAFS Analysis of FeThe x(k)
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Table 8.4 EXAFS Results of HFO and
Page 146 and 147:
CHAPTER 9SURFACE COMPLEXATION MODEL
Page 148 and 149:
Figure 9.1 Potentiometric titration
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128Table 9.1 Surface Reactions and
Page 152 and 153:
Page 154 and 155:
132Table 9.2 Model Parameters for N
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Page 158 and 159:
1369.3 Zn Adsorption on GoethiteReg
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Figure 9.6 Zn adsorption</s
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140data over a broad range of condi
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142Figure 9.8 Ni adsorption
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144oxide-coated silica. Ni and Zn s
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Page 170 and 171:
Figure 10.2 Zn adsorption</
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152one for GACS (2.77x10 -6 mole si
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Figure 10.6 Zn adsorption</
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CHAPTER 11CONCLUSIONS AND FUTURE WO
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158surfaces are needed for successf
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Figure A.2 Ni speciation in 1x10 -5
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Figure A.4 Pb speciation in 5x10 -8
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Figure A.6 Zn speciation in 1x10 -5
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166Table B.2 Potentiometric Titrati
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168Table BA Potentiometric Titratio
Page 192 and 193:
170Table C.3 Zn Adsorption Edges on
Page 194 and 195:
APPENDIX DADSORPTION STUDIES ON SIL
Page 196 and 197:
174Table D.5 Zn Adsorption Isotherm
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176Table E.3 Pb CBC Study on 0.3 g
Page 200 and 201:
APPENDIX GINTRAPARTICLE DIFFUSION M
Page 202 and 203:
180DofA = flier ^ 2fA = Exp(-fD * f
Page 204 and 205:
REFERENCES1. Adamson A. W. (1982) P
Page 206 and 207:
18426. Blake R. L., Hessevick R. E.
Page 208 and 209:
18650. Combes J. M., Manceau A. and
Page 210 and 211:
18876. Elzinga E. J. and Sparks D.
Page 212 and 213:
190102. Gupta V. K. (1998) Equilibr
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192126. Joshi A. and Chaudhuri M. (
Page 216 and 217:
194150. Liu C. and Huang P. M. (200
Page 218 and 219:
196175. Muller B. and Sigg L. (1992
Page 220 and 221:
200. Perry R. H. and Green D. W. (1
Page 222 and 223:
200226. Scheinost A. C., Kretzschma
Page 224 and 225:
202252. Swallow C. K., Hume D. N. a
Page 226 and 227:
204278. Villalobos M., Trotz M. A.
Page 228:
304. Zhong Z. Y., Prozorov T., Feln
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