UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

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U(IV) and U(VI) can form stable organic complexes, thereby increasing their solubility and mobility. Table 5.16. Uranium(VI) aqueous species included in the speciation calculations. Aqueous Species 2+ UO2 , UO2OH + N - 2- , UO2(OH) 2(aq), UO2(OH) 3, , UO2(OH) 4 , (UO2) 2OH3+ 2+ 2+ + , (UO2) 2(OH) 2 , (UO2) 3(OH) 4 , (UO2) 3(OH) 5, + 9+ , U6(OH) 15 - (UO2) 3(OH) 7, (UO2) 4(OH) 7 N 2- 4- 5- UO2CO3(aq), UO2(CO3) 2 , UO2(CO3) 3 , UO2(CO3) 3 , 6- 2 , (UO2) 11(CO3) 6(OH) 12 (UO 2) 3(CO 3) 6 5.69 - - , (UO2) 2CO3(OH) 3 - N + 2+ UO2PO4, UO2HPO4(aq), UO2H2PO4, UO2H3PO4 , N UO2(H2PO4) 2(aq), UO2(H2PO4)(H3PO4) + , N 2- UO2SO4(aq), UO2(SO4) 2 + UO2NO3 UO2Cl + N , UO2Cl2(aq), UO2F + N - 2- , UO2F2(aq), UO2F3, UO2F4 + UO2SiO(OH) 3 5.11.4 Dissolution/Precipitation/Coprecipitation Dissolution, precipitation, and coprecipitation have a much greater effect on the concentrations of U(IV) than on the concentration of U(VI) in groundwaters. In most cases, these processes will likely not control the concentration of U(VI) in oxygenated groundwaters far from a uranium source. Near a uranium source, or in reduced environments, these processes tend to become increasingly important and several (co)precipitates may form depending on the environmental conditions (Falck, 1991; Frondel, 1958). Reducing conditions may exist in deep aquifers, marsh areas, or engineered barriers that may cause U(IV) to precipitate. Important U(IV) minerals include uraninite (compositions ranging from UO 2 to UO 2.25), coffinite (USiO 4), and ningyoite [CaU(PO 4) 2·2H 2O] (Frondel, 1958; Langmuir, 1978). Important U(VI) minerals include carnotite [(K 2(UO 2) 2(VO 4) 2], schoepite (UO 3·2H 2O), rutherfordine (UO 2CO 3), tyuyamunite [Ca(UO 2) 2(VO 4) 2], autunite [Ca(UO 2) 2(PO 4) 2], potassium autunite [K 2(UO 2) 2(PO 4) 2], and uranophane [Ca(UO 2) 2(SiO 3OH) 2] (Frondel, 1958; Langmuir, 1978). Carnotite, a U(VI) mineral, is found in the oxidized zones of uranium ore deposits and uraninite, a U(IV) mineral, is a primary
mineral in reducing ore zones (Frondel, 1958). The best way to model the concentration of precipitated uranium is not with the K d construct, but through the use of solubility constants. Percent Distribution 100 80 60 40 20 0 2+ UO2 UO2OH + 3 4 5 6 7 8 9 10 5.70 o UO2(OH)2 (aq) pH - UO2(OH)3 Figure 5.6a. Calculated distribution of U(VI) hydrolytic species as a function of pH at 0.1 µg/l total dissolved U(VI). [The species distribution is based on U(VI) dissolved in pure water (i.e., absence of complexing ligands other than OH - ) and thermodynamic data from Wanner and Forest (1992).]
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United States Office of Air and Rad
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NOTICE The following two-volume rep
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This publication is the result of a
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TO COMMENT ON THIS GUIDE OR PROVIDE
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CONTENTS NOTICE ...................
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Concentrations Extractable Iron Con
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Appendix A - Acronyms and Abbreviat
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Figure E.1. Variation of K d for Cr
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Table 5.16. Uranium(VI) aqueous spe
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Table H.3. Simple and multiple regr
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1.0 Introduction The objective of t
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discussed. The geochemical modeling
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2.0 The K d Model The simplest and
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track many more parameters and some
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of interest. The retardation factor
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(e.g., soil). An increasing body of
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complexation constants for the cont
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the soil column. Additionally, the
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Element Table 5.2. Concentrations o
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5.2.3 Aqueous Speciation Cadmium fo
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5.2.4 Dissolution/Precipitation/Cop
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cadmium, indicating that cadmium an
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5.2.6.2.2 Limits of K d Values with
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5.3.4 Dissolution/Precipitation/Cop
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organic chelates (e.g., EDTA). Init
Page 51 and 52: 5.3.6.2.1 Limits of K d Values with
Page 53 and 54: (tarapacaite) in chromium sludge fr
Page 55 and 56: K d). Soils containing Mn oxides ox
Page 57 and 58: Table 5.7. Estimated range of Kd va
Page 59 and 60: most common valence state of lead e
Page 61 and 62: Table 5.8. Lead aqueous species inc
Page 63 and 64: Under reducing conditions, galena (
Page 65 and 66: C Adsorption of lead increases with
Page 69 and 70: (Choppin, 1983). Plutonium hydrolyt
Page 71 and 72: Table 5.10. Plutonium aqueous speci
Page 73 and 74: 5.6.5 Sorption/Desorption Plutonium
Page 75 and 76: content in the system. Additionally
Page 79 and 80: 5.7.4 Dissolution/Precipitation/Cop
Page 81 and 82: much greater concentrations. Thus,
Page 83 and 84: exchanged which they attributed to
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Page 87 and 88: organic complexes likely predominat
Page 89 and 90: Thorium undergoes hydrolysis in aqu
Page 91 and 92: The distribution of thorium aqueous
Page 93 and 94: from about 10 -8.5 mol/l (0.0007 mg
Page 95 and 96: Based on the assumptions and limita
Page 97 and 98: 5.10 Tritium Geochemistry And K d V
Page 99 and 100: uranium. Uranium(VI) species domina
Page 101: gives 0.1 to 10 µg/l as the range
Page 105 and 106: Percent Distribution 100 80 60 40 2
Page 107 and 108: 5.11.6 Partition Coefficient, K d ,
Page 109 and 110: No attempt was made to statisticall
Page 111 and 112: Table 5.18. Selected chemical and t
Page 113 and 114: Another objective of this report is
Page 115 and 116: 6.0 REFERENCES Adriano, D. C. 1992.
Page 117 and 118: Bensen, D. W. 1960. Review of Soil
Page 119 and 120: Metals by Geomedia. Variables, Mech
Page 121 and 122: EPA (U.S. Environmental Protection
Page 123 and 124: Griffin, R. A., A. K. Au, and R. R.
Page 125 and 126: + Keeney-Kennicutt, W. L., and J. W
Page 127 and 128: Mattigod, S. V., A. L. Page, and I.
Page 129 and 130: Oscarson, D. W., and H. B. Hume. 19
Page 131 and 132: Relyea, J. F. and D. A. Brown. 1978
Page 133 and 134: Schultz, R. K., R. Overstreet, and
Page 135 and 136: Szalay, A. 1964. “Cation Exchange
Page 137 and 138: Yariv, S., and H. Cross. 1979. Geoc
Page 139 and 140: APPENDIX A Acronyms, Abbreviations,
Page 141 and 142: PC Personal computers operating und
Page 143 and 144: A.3.0 List of Symbols and Notation
Page 145 and 146: APPENDIX B Definitions
Page 147 and 148: Clay Content - particle size fracti
Page 149 and 150: Polynuclear Species - an aqueous sp
Page 151 and 152: C.1.0 Background Appendix C Partiti
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Cadmium K d Table C.2. Correlation
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C.3.0 Data Set for Soils Table C.4
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Cd K d (ml/g) Clay Cont. (wt%) pH C
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D.1.0 Background Appendix D Partiti
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A second data set (see Section D.4)
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Table D.3. Correlation coefficients
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By transposing the CEC and cesium K
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Table D.6. Cesium K d values measur
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eported in Table D.8 are described
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a 1 b 1 Range of Solution Cs Concen
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Figure D.4. Generalized cesium Freu
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Table D.10. Estimated range of K d
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D.3.0 K d Data Set for Soils and Pu
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Cesium Kd (ml/g) Clay (wt.% ) Mica
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Cesium K d (ml/g) Clay (wt%) Mica (
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Bruggenwert, M. G. M., and A. Kamph
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Shiao, S. Y., P. Rafferty, R. E. Me
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E.1.0 Background Appendix E Partiti
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chromium-reductive soils may stem f
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E.2.0 Approach The approach used to
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Table E.3. Estimated range of K d v
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Table E.4. Data from Rai et al. (19
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E.4.0 References Davis, J. A. and J
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APPENDIX F Partition Coefficients F
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(CEC) of the soils. Such an anomaly
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Table F.1. Summary of K d values fo
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Figure F.2. Variation of K d as a f
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F.4.0 References Abd-Elfattah, A.,
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APPENDIX G Partition Coefficients F
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A number of investigators have exam
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pH value, which is typical of the m
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These significant reductions in ads
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This is typically accomplished by t
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The scatterplots are typically disp
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Table G.2. Regression models for pl
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G.4.0 References Barney, G. S. 1984
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Nelson, D. M., R. P. Larson, and W.
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APPENDIX H Partition Coefficients F
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1.6 ml/g for a measurement made on
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Figure H.1. Relation between stront
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Figure H.2. Relation between stront
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H.2.4 Approach Figure H.4. Relation
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A second look-up table (Table H.5)
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Sr K d (ml/g) Clay Content (%) pH C
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Sr K d (ml/g) Clay Content (%) pH C
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Sr K d (ml/g) Clay Conten t (%) pH
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Konishi, M., K. Yamamoto, T. Yanagi
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APPENDIX I Partition Coefficients F
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descriptive statistics of the thori
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Figure I.1. Linear regression betwe
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The look-up table (Table I.5) for t
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Thorium K d (ml/g) pH Clay (wt.%) C
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Rai, D., A. R. Felmy, D. A. Moore,
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J.1.0 Background Appendix J Partiti
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J.2.2 Uranium K d Studies on Soils
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Washington. The studies included an
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and then decreases with increasing
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Kd (ml/g) 100,000 10,000 1,000 100
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papers. Warnecke et al. (1984) indi
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Anderson et al. (1982) summarize an
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McKinley and Scholtis (1993) compar
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In a similar comparison of sorption
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J.3.1 K d Values as a Function ff p
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discussed, and one would have to ma
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al., 1992; and others). These refer
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· Manskaya et al. (1956) studied a
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concentrations of humic acid, there
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pH U Kd (ml/g) Clay Cont. (wt.%) CE
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J.6.0 References Ames, L. L., J. E.
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Erikson, R. L., C. J. Hostetler, R.
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R. C. Ewing. Materials Research Soc
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Sheppard, M. I., and D. H. Thibault
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Yamamoto, T., E. Yunoki, M. Yamakaw
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