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

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LIST OF FIGURESFigurePage5.1 Potentiometric titration of goethite (1 g L-1 ) at room temperature. 465.2 X-Ray diffraction patterns of US silica and Alfa Aesar silica (the numbersets identify the crystal planes). 485.3 Particle size distribution for Alfa Aesar silica as a function of pH and ionicstrengths. 525.4 Particle size distribution for US silica as a function of pH and ionic strength 535.5 ESEM micrograph for Alfa Aesar silica. 555.6 ESEM micrograph for US silica 555.7 Micrograph of Alfa Aesar silica. 565.8 Micrograph of US silica. 565.9 Micrograph of goethite. 575.10 Potentiometric titration of 2 g L -1 acid-washed US silica with 0.1, 1, and10 N NaOH where 1 N HNO3 was used to adjust initial pH. Titration wasconducted under a N2 pressure of 35 psi. 606.1 Comparison between Fe. before and after abrasion studies. Experiments 1through 9 are based on the <strong>adsorption</strong> method, and 10 through 18 theprecipitation method; column (a) represents Feconc before abrasion, andcolumn (b) is that after abrasion 646.2 XRD patterns for goethite, silica, goethite-coated silica, and residual goethiteproduced in the coating process. 666.3 XRD analysis of goethite produced in coating 676.4 Effect of coating conditions from the fractional factorial study. 696.5 FTIR spectra of a. silica; b. goethite-coated silica (21.36 mg Fe g -1 solid,coated with <strong>adsorption</strong> method at pH 7.5 and 60 °C); c. physically mixedgoethite and silica (20.76 mg Fe g -1 solid); and d. goethite. The 1390 cm -1peak reveals existence of the NO 3- impurity in the goethite sample 71xiv
LIST OF FIGURES(Continued)FigurePage6.6 Optical micrograph of uncoated and coated US silica (1 cm in photographrepresents 0.2 mm of real size) 736.7 ESEM micrograph (9000x) of goethite-coated silica (after abrasion): upper isa rough area of goethite-coated silica using the <strong>adsorption</strong> method; lower is asmooth area of goethite-coated silica employing the precipitation approach. 746.8 EDX results of goethite-coated silica (white images in mapping represent thecorresponding element). 756.9 Pore size distribution (right) and particle size distribution (left) of uncoatedand coated silica. (For particle size distribution: • IS=0.1, A IS=0.01, V IS=0.001 using NaNO3, pH 6, average size of silica sample is 0.9 mm, 0.3 g L -1 ) 776.10 Surface charge distribution of silica, goethite, and goethite-coated silica (1 gL-1 solid). Ionic strength adjusted with NaNO3: • IS=0.1, A IS=0.01, V IS=0.001. The PZC of the adsorbed goethite-coated silica is based on thecrossover of two titration curves and the average pH at which zero chargeoccurred under each ionic strength. All other PZCs were determined by thecrossover of three titration curves. 806.11 Ni <strong>adsorption</strong> edges on silica (5 g L -1 ), goethite-coated silica (5 g L -1 , Feconcentration 4.01 mg Fe g-1 silica), and goethite (1 g L -1), at ionic strength0.01 (NaNO3), [Ni]0=5x10 1° M, and 25 °C with 4 hours equilibration time.Estimated <strong>adsorption</strong> on coated silica was calculated based on weight fractionpresent of each surface. 827.1 EXAFS spectra of Pb standards and 4-hour Pb/HFO sample at Pb L m-edge 877.2 EXAFS spectra of Pb/HFO samples at pH 5 and IS 10 -2 as a function of timeat Pb Lllredge. 887.3 Fourier transform and fit of Pb standards spectra at Pb L111 edge. FT wasperformed over range: PbO 3.0-10.8 A -1 , PbCO3 2.08-9.79 A -1 , Pb2+ 2.26-8.48 k 1 ; PbO was fitted over 0.74-3.95 A, PbCO3 0.46-4.69 A, and Pb2+0.42-3.0 A. Lines represent data, dashed lines represent fit 907.4 Fourier transform and fit of 4-hour Pb/HFO <strong>adsorption</strong> samples at Pb L 111edge. FT was performed over range 2.8-9.5 A -1 , fitted over 0.45-3.58 A 92xv
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: LIST OF TABLES(Continued)TablePageB
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 and 32: 9identify components, distribution,
Page 33 and 34: 11oxides. Because extraction method
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
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47measured by potentiometric titrat
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Table 5.2 XRD Data of Alfa Aesar (A
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51Table 5.3 XRF Results for Alfa Ae
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Figure 5.4 Particle size distributi
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55Figure 5.5 ESEM micrograph for Al
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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
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1208.3 EXAFS Analysis of FeThe x(k)
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Table 8.4 EXAFS Results of HFO and
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CHAPTER 9SURFACE COMPLEXATION MODEL
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Figure 9.1 Potentiometric titration
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128Table 9.1 Surface Reactions and
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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
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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
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180DofA = flier ^ 2fA = Exp(-fD * f
Page 204 and 205:
REFERENCES1. Adamson A. W. (1982) P
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18426. Blake R. L., Hessevick R. E.
Page 208 and 209:
18650. Combes J. M., Manceau A. and
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18876. Elzinga E. J. and Sparks D.
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190102. Gupta V. K. (1998) Equilibr
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192126. Joshi A. and Chaudhuri M. (
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194150. Liu C. and Huang P. M. (200
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196175. Muller B. and Sigg L. (1992
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200. Perry R. H. and Green D. W. (1
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200226. Scheinost A. C., Kretzschma
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202252. Swallow C. K., Hume D. N. a
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204278. Villalobos M., Trotz M. A.
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304. Zhong Z. Y., Prozorov T., Feln
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