UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

More documents

Recommendations

Info

minimum and maximum K d values for uranium as a function of pH. These values are listed in Table 5.17. For K d values at non-integer pH values, especially given the rapid changes in uranium adsorption observed at pH values less than 5 and greater than 8, the reader should assume a linear relationship between each adjacent pair of pH-K d values listed in Table 5.17. Table 5.17. Look-up table for estimated range of K d values for uranium based on pH. K d (ml/g) 5.75 pH 3 4 5 6 7 8 9 10 Minimum
No attempt was made to statistically fit the K d values summarized in Appendix J as a function of dissolved carbonate concentrations. Typically carbonate concentrations were not reported and/or discussed, and one would have to make assumptions about possible equilibrium between the solutions and atmospheric or soil-related partial pressures of CO 2 or carbonate phases present in the soil samples. Given the complexity of these reaction processes, it is recommended that the reader consider the application of geochemical reaction codes, and surface complexation models in particular, as the best approach to predicting the role of dissolved carbonate in the adsorption behavior of uranium and derivation of U(VI) K d values when site-specific K d values are not available. 5.11.6.2.2 Limits of K d Values with Respect to Clay Content and CEC No attempt was made to statistically fit the K d values summarized in Appendix J as a function of clay content or CEC. The extent of clay content and CEC data, as noted from information compiled during this review, is limited to a few studies that cover somewhat limited geochemical conditions. Moreover, Serkiz and Johnson (1994) found no correlation between their uranium in situ K d values and the clay content or CEC of their soils. Their systems covered the pH conditions from 3 to 7. However, clays have an important role in the adsorption of uranium in soils. Attempts have been made (e.g., Borovec, 1981) to represent this functionality with a mathematical expression, but such studies are typically for limited geochemical conditions. Based on studies by Chisholm-Brause (1994), Morris et al. (1994), McKinley et al. (1995), Turner et al. (1996), and others, uranium adsorption onto clay minerals is complicated and involves multiple binding sites, including exchange and edge-coordination sites. The reader is referred to these references for a detailed treatment of the uranium adsorption on smectite clays and application of surface complexation modeling techniques for such minerals. 5.11.6.2.3 Use of Surface Complexation Models to Predict Uranium K d Values As discussed in Chapter 4 and in greater detail in Volume I of this report, electrostatic surface complexation models (SCMs) incorporated into chemical reaction codes, such as EPA’s M<strong>IN</strong>TEQA2, may be used to predict the adsorption behavior of some radionuclides and other metals and to derive K d values as a function of key geochemical parameters, such as pH and carbonate concentrations. Typically, the application of surface complexation models is limited by the availability of surface complexation constants for the constituents of interest and competing ions that influence their adsorption behavior. The current state of knowledge regarding surface complexation constants for uranium adsorption onto important soil minerals, such as iron oxides, and development of a mechanistic understanding of these reactions is probably as advanced as those for any other trace metal. In the absence of site-specific K d values for the geochemical conditions of interest, the reader is encouraged to 5.76
Page 1 and 2:
United States Office of Air and Rad
Page 3 and 4:
NOTICE The following two-volume rep
Page 5 and 6:
This publication is the result of a
Page 7 and 8:
TO COMMENT ON THIS GUIDE OR PROVIDE
Page 9 and 10:
CONTENTS NOTICE ...................
Page 11 and 12:
Concentrations Extractable Iron Con
Page 13 and 14:
Appendix A - Acronyms and Abbreviat
Page 15 and 16:
Figure E.1. Variation of K d for Cr
Page 17 and 18:
Table 5.16. Uranium(VI) aqueous spe
Page 19 and 20:
Table H.3. Simple and multiple regr
Page 21 and 22:
1.0 Introduction The objective of t
Page 23 and 24:
discussed. The geochemical modeling
Page 25 and 26:
2.0 The K d Model The simplest and
Page 27 and 28:
track many more parameters and some
Page 29 and 30:
of interest. The retardation factor
Page 31 and 32:
(e.g., soil). An increasing body of
Page 33 and 34:
complexation constants for the cont
Page 35 and 36:
the soil column. Additionally, the
Page 37 and 38:
Element Table 5.2. Concentrations o
Page 39 and 40:
5.2.3 Aqueous Speciation Cadmium fo
Page 41 and 42:
5.2.4 Dissolution/Precipitation/Cop
Page 43 and 44:
cadmium, indicating that cadmium an
Page 45 and 46:
5.2.6.2.2 Limits of K d Values with
Page 47 and 48:
5.3.4 Dissolution/Precipitation/Cop
Page 49 and 50:
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 67 and 68: 5.5.6.2.2 Limits of K d Values 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 77 and 78: 5.6.6.2.2 Limits of K d Values with
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
Page 85 and 86: up tables was based in part on thei
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 and 102: gives 0.1 to 10 µg/l as the range
Page 103 and 104: mineral in reducing ore zones (Fron
Page 105 and 106: Percent Distribution 100 80 60 40 2
Page 107: 5.11.6 Partition Coefficient, K d ,
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
Page 153 and 154: Cadmium K d Table C.2. Correlation
Page 155 and 156: C.3.0 Data Set for Soils Table C.4
Page 157 and 158: Cd K d (ml/g) Clay Cont. (wt%) pH C
Page 159 and 160:
Cd K d (ml/g) Clay Cont. (wt%) pH C
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
D.1.0 Background Appendix D Partiti
Page 169 and 170:
A second data set (see Section D.4)
Page 171 and 172:
Table D.3. Correlation coefficients
Page 173 and 174:
By transposing the CEC and cesium K
Page 175 and 176:
Table D.6. Cesium K d values measur
Page 177 and 178:
eported in Table D.8 are described
Page 179 and 180:
a 1 b 1 Range of Solution Cs Concen
Page 181 and 182:
Figure D.4. Generalized cesium Freu
Page 183 and 184:
Table D.10. Estimated range of K d
Page 185 and 186:
D.3.0 K d Data Set for Soils and Pu
Page 187 and 188:
Cesium Kd (ml/g) Clay (wt.% ) Mica
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Cesium K d (ml/g) Clay (wt%) Mica (
Page 195 and 196:
Bruggenwert, M. G. M., and A. Kamph
Page 197 and 198:
Shiao, S. Y., P. Rafferty, R. E. Me
Page 199 and 200:
E.1.0 Background Appendix E Partiti
Page 201 and 202:
chromium-reductive soils may stem f
Page 204 and 205:
E.2.0 Approach The approach used to
Page 206 and 207:
Table E.3. Estimated range of K d v
Page 208 and 209:
Table E.4. Data from Rai et al. (19
Page 210 and 211:
E.4.0 References Davis, J. A. and J
Page 212 and 213:
APPENDIX F Partition Coefficients F
Page 214 and 215:
(CEC) of the soils. Such an anomaly
Page 216 and 217:
Table F.1. Summary of K d values fo
Page 218 and 219:
Figure F.2. Variation of K d as a f
Page 220 and 221:
F.4.0 References Abd-Elfattah, A.,
Page 222 and 223:
APPENDIX G Partition Coefficients F
Page 224 and 225:
A number of investigators have exam
Page 226 and 227:
pH value, which is typical of the m
Page 228 and 229:
These significant reductions in ads
Page 230 and 231:
This is typically accomplished by t
Page 232 and 233:
The scatterplots are typically disp
Page 234 and 235:
Table G.2. Regression models for pl
Page 236 and 237:
G.4.0 References Barney, G. S. 1984
Page 238 and 239:
Nelson, D. M., R. P. Larson, and W.
Page 240 and 241:
APPENDIX H Partition Coefficients F
Page 242 and 243:
1.6 ml/g for a measurement made on
Page 244 and 245:
Figure H.1. Relation between stront
Page 246 and 247:
Figure H.2. Relation between stront
Page 248 and 249:
H.2.4 Approach Figure H.4. Relation
Page 250 and 251:
A second look-up table (Table H.5)
Page 252 and 253:
Sr K d (ml/g) Clay Content (%) pH C
Page 254 and 255:
Sr K d (ml/g) Clay Content (%) pH C
Page 256 and 257:
Sr K d (ml/g) Clay Conten t (%) pH
Page 258 and 259:
Page 260 and 261:
Page 262 and 263:
Page 264 and 265:
Konishi, M., K. Yamamoto, T. Yanagi
Page 266 and 267:
APPENDIX I Partition Coefficients F
Page 268 and 269:
descriptive statistics of the thori
Page 270 and 271:
Figure I.1. Linear regression betwe
Page 272 and 273:
The look-up table (Table I.5) for t
Page 274 and 275:
Thorium K d (ml/g) pH Clay (wt.%) C
Page 276 and 277:
Rai, D., A. R. Felmy, D. A. Moore,
Page 278 and 279:
J.1.0 Background Appendix J Partiti
Page 280 and 281:
J.2.2 Uranium K d Studies on Soils
Page 282 and 283:
Washington. The studies included an
Page 284 and 285:
and then decreases with increasing
Page 286 and 287:
Kd (ml/g) 100,000 10,000 1,000 100
Page 288 and 289:
papers. Warnecke et al. (1984) indi
Page 290 and 291:
Anderson et al. (1982) summarize an
Page 292 and 293:
McKinley and Scholtis (1993) compar
Page 294 and 295:
In a similar comparison of sorption
Page 296 and 297:
J.3.1 K d Values as a Function ff p
Page 298 and 299:
discussed, and one would have to ma
Page 300 and 301:
al., 1992; and others). These refer
Page 302 and 303:
· Manskaya et al. (1956) studied a
Page 304 and 305:
concentrations of humic acid, there
Page 306 and 307:
pH U Kd (ml/g) Clay Cont. (wt.%) CE
Page 308 and 309:
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Page 316 and 317:
Page 318 and 319:
Page 320 and 321:
Page 322 and 323:
Page 324 and 325:
Page 326 and 327:
J.6.0 References Ames, L. L., J. E.
Page 328 and 329:
Erikson, R. L., C. J. Hostetler, R.
Page 330 and 331:
R. C. Ewing. Materials Research Soc
Page 332 and 333:
Sheppard, M. I., and D. H. Thibault
Page 334:
Yamamoto, T., E. Yunoki, M. Yamakaw
show all

UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd ...

Create successful ePaper yourself

Delete template?

Save as template?