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Comparison of Measured and Calculated Diffusion Coefficients for Iodide in Compacted Clays

Published online by Cambridge University Press:  09 July 2018

D. W. Oscarson
D. W. Oscarson*
Affiliation:
AECL Research, Whiteshell Laboratories, Pinawa, Manitoba, Canada ROE 1LO
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Abstract

An understanding of the behaviour of contaminants in compacted clays is important in assessing the effectiveness of clay-based barrier materials used in many waste containment strategies. Here the diffusion and sorption behaviour of I− with selected compacted clays is examined (129I is a relatively long-lived radioisotope present in high-level nuclear fuel waste.) Diffusion coefficients, D, and distribution coefficients, Kd , were measured for I− with four clays: bentonite, Lake Agassiz clay (a glacial lake clay composed mainly of smectite, illite, kaolinite, and quartz), interstratified illite-smectite, and kaolinite. For the diffusion experiments the clays were compacted to a dry bulk density, ρ, of ∼1.2 Mg m−3. The mean measured D values, D m, were as follows: bentonite, 310 µm2 s−1; Lake Agassiz clay, 0.62 µm2 s−1; illitesmectite, 190µm2s−1; and kaolinite, 74µm2s−1. The measured values were compared with those calculated, D c, from the following model: D=D oτa n/(n + ρKd ), where Do is the diffusion coefficient in pure bulk water, τ a the apparent tortuosity factor, and n the solution-filled porosity of the clay. Except for the Lake Agassiz clay, where D m was about an order of magnitude lower than D c, the D m and D c values agreed within a factor of about two. The Lake Agassiz clay has a markedly higher organic carbon content than the other three clays, and this could affect τ a, which may be overestimated in the model.

Information

Type
Research Article
Information
Clay Minerals , Volume 29 , Issue 2 , June 1994, pp. 145 - 151
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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References

Allard, B., TorstenfeltB., Andersson, K. & Rydberg, J. (1980) Possible retention of iodine in the ground. Pp. 673-680 in: Scientific Basis for Nuclear Waste Management, Vol. 2. (C.J.M. Northrup, Jr., editor) Plenum, New York.Google Scholar
Carter, D.L., Mortland, M.M. & Kemper, W.D. (1986) Specific surface. Pp. 413-123 in: Methods of Soil Analysis, (A. Klute, editor), Part 1, 2nd ed. ASA and SSSA, Madison, Wisconsin.Google Scholar
Cho, W.J., Oscarson, D.W., Gray, M.N. & Cheung, S.C.H. (1993a) Influence of diffusant concentration on diffusion coefficients in clay. Radiochim. Act, 60, 159–163.Google Scholar
Cho, W.J., Oscarson, D.W. & Hahn, P.S. (1993b) The measurement of apparent diffusion coefficients in compacted clays: An assessment of methods Appl. Clay Sci, 8, 283–294.Google Scholar
Couture, R.A. & Seitz, M.G. (1983) Sorption of anions of iodine by iron oxides and kaolinite. Nucl. Chem. Waste Manage, 4, 301–306..Google Scholar
Crank, J. (1975) The Mathematics of Diffusion. 2nd ed. Clarendon Press, Oxford.Google Scholar
De, S.K. (1961) A study on the adsorptive behaviour of iodide with silicate minerals. Nat. Acad. Sci. (India), Proc. Sec. A, 30, 195–199.Google Scholar
Frape, S.K., Fritz, P. & McNutt, R.H. (1984) Water-rock interaction and chemistry of groundwaters from the Canadian Shield. Geochim Cosmochim. Act, 48, 1617–1627.Google Scholar
Gillham, R.W. & Cherry, J.A. (1982) Contaminant migration in saturated unconsolidated geologic deposits. Pp. 31-62 in: Recent Trends in Hydrogeology (T.N. Narasim- han, editor). GSA Special Paper 189. Geological Society of America, Boulder, Colorado.Google Scholar
Hancox, W.T. & Nuttall, K. (1991) The Canadian approach to safe, permanent disposal of nuclear fuel waste. Nucl. Eng. Desig, 129, 109–117.Google Scholar
Jackson, M.L. (1975) Soil Chemical Analysis—Advanced Course,2nd ed. Published by the author, University of Wisconsin, Madison, Wisconsin.Google Scholar
Kemper, W.D. (1986) Solute diffusivity. Pp. 1007-1024 in: Methods of Soil Analysis. (A. Klute, editor), Part 1, 2nd ed. ASA and SSSA, Madison, Wisconsin.Google Scholar
Nelson, D.W. & Sommers L:E. (1982) Total carbon, organic carbon, and organic matter. Pp. 539-579 in: Methods of Soil Analysis. (A.L. Page R.H. Miller & D.R. Keeney, editors), Part 2. ASA and SSSA, Madison, Wisconsin.Google Scholar
Oscarson, D.W. & Dixon, D.A. (1989) Elemental, mineralogical, and pore-solution compositions of selected Canadian clays. AECL Research Report, AECL-9891. AECL Research, Chalk River, Ontario.Google Scholar
Oscarson, D.W. & Hume, H.B. (1993) On the smectite to illite reaction. AECL Research Report, AECL-10842. AECL Research, Chalk River, Ontario.Google Scholar
Oscarson, D.W., Dixon, D.A. & Gray, M.N. (1990) Swelling capacity and permeability of an unprocessed and a processed bentonitic clay. Eng. Geol, 28, 281–289.Google Scholar
Oscarson, D.W., Watson, R.L. & LeNeveu, D.M. (1984) A compilation of distribution coefficients for radioactive and other toxic contaminants with bentonite for use in SYVAC. AECL Research Technical Record, TR-288. AECL Research, Chalk River, Ontario.Google Scholar
Oscarson, D.W., Hume, H.B., Sawatsky, N.G. & Cheung, S.C.H. (1992) Diffusion of iodide in compacted bentonite. Soil Sci. Soc. Am. J, 56, 1400–1406.Google Scholar
Robin, M.J.L., Gillham, R.W. & Oscarson, D.W. (1987) Diffusion of strontium and chloride in compacted clay- based materials. Soil Sci. Soc. Am. J, 51, 1102–1108.Google Scholar
Sawatsky, N.G. & Oscarson, D.W. (1991) Diffusion of technetium in dense bentonite under oxidizing and reducing conditions. Soil Sci. Soc. Am. J. 55, 1261–1267.Google Scholar
Shackelford, C.D. & Daniel, D.E. (1991a) Diffusion in saturated soil. II: Results for compacted clay. J. Geotech. Eng, 117, 485–506.Google Scholar
Shackelford, C.D. & Daniel, D.E. (1991b) Diffusion in saturated soil. I: Background. J. Geotech. Eng, 117, 467–184.Google Scholar
Sharma, H.D. & Oscarson, D.W. (1989) Diffusion of plutonium(IV) in dense bentonite-based materials. Pp. 735-741 in: Scientific Basis for Nuclear Waste Management XII (W. Lutze & R.C. Ewing, editors), MRS Proceedings Vol. 127, Materials Research Society, Pittsburgh, Pennsylvania.Google Scholar
Sheppard, M.I. & Thibault, D.H. (1991) A four-year mobility study of selected trace elements and heavy metals. J. Environ. Qual, 20, 101–114.Google Scholar