Hostname: page-component-848d4c4894-2pzkn Total loading time: 0 Render date: 2024-06-01T20:00:01.291Z Has data issue: false hasContentIssue false

Effects of Structural Iron Reduction on the Hydraulic Conductivity of Na-Smectite

Published online by Cambridge University Press:  28 February 2024

Siyuan Shen
Affiliation:
Department of Agronomy, University of Illinois, Urbana, Illinois 61801
Joseph W. Stucki
Affiliation:
Department of Agronomy, University of Illinois, Urbana, Illinois 61801
Charles W. Boast*
Affiliation:
Department of Agronomy, University of Illinois, Urbana, Illinois 61801
*
1Graduate Research Assistant, Professor of Soil Physical Chemistry, and Professor of Soil Physics, respectively, Department of Agronomy, University of Illinois, 1102 South Goodwin Avenue, Urbana, Illinois 61801, USA

Abstract

The long-term impermeability of clay barriers in waste disposal facilities and hydraulic structures is of critical importance to environmental, agricultural, and industrial concerns. Changes in the oxidation state of Fe in the constituent clays of compacted clay barriers may degrade the hydraulic conductivity of these structures because other properties related to hydraulic conductivity, such as swelling, gel microstructure, and particle size, are greatly altered by the oxidation state. Two Na-saturated smectites (SWa-1 and API 25) were reduced by sodium dithionite (Na2S2O4), both in suspension and in situ after consolidation, to examine the effects of structural Fe reduction on hydraulic conductivity. Results indicated that the hydraulic conductivity depended on both the oxidation state and the consolidation history of the clay. The hydraulic conductivity of clay reduced in suspension before consolidation was lower than that of oxidized clay. Initially reduced smectite, thus, may be compactable to a less-permeable material with higher bulk density. But reduction of smectite in situ after consolidation increased the hydraulic conductivity and its variability. The oxidized state of clay liners should, therefore, be preserved.

Type
Research Article
Copyright
Copyright © 1992, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Albrecht, K. A. and Cartwright, K., 1989 Infiltration and hydraulic conductivity of a compacted earthen liner Ground Water 27 1419 10.1111/j.1745-6584.1989.tb00002.x.CrossRefGoogle Scholar
Anderson, D. C., 1981 Organic leachate effects of the permeability of clay soils Texas Texas A&M University, College Station.Google Scholar
Blackmore, A. V. and Marshall, T. J., 1965 Water movement through a swelling material Aust. J. Soil Res 3 1121 10.1071/SR9650011.CrossRefGoogle Scholar
Buchanan, P. N., 1964 Effect of temperature and adsorbed water on permeability and consolidation characteristics of sodium and calcium montmorillonite Texas Texas A&M University, College Station.Google Scholar
Chen, S. Z., Low, P. F. and Roth, C. B., 1987 Relation between potassium fixation and the oxidation state of octahedral iron Soil Sci. Soc. Amer. J 51 8286 10.2136/sssaj1987.03615995005100010017x.CrossRefGoogle Scholar
Goldman, L. J., Greenfield, L. I., Damle, A. S., Kingsbury, G. L., Northeim, C. M. and Truesdale, R. S., 1988 Design, construction, and evaluation of clay for waste management facilities .Google Scholar
Goodman, B. A., Russell, J. D. and Fraser, A. R., 1976 A Mössbauer and I.R. spectroscopic study of the structure of nontronite Clays & Clay Minerals 24 5359 10.1346/CCMN.1976.0240201.CrossRefGoogle Scholar
Khaled, E. M. and Stucki, J. W., 1991 Iron oxidation state effects on cation fixation in smectites Soil Sci. Soc. Amer. J 55 550554 10.2136/sssaj1991.03615995005500020045x.CrossRefGoogle Scholar
Klute, A., Dirksen, C. and Klute, A., 1986 Hydraulic conductivity and diffusivity: Laboratory methods Methods of Soil Analysis, Part 1, Physical and Mineralogic Methods 2nd Madison Soil Science Society of America 687731.CrossRefGoogle Scholar
Komadel, P. and Stucki, J. W., 1988 Quantitative assay of minerals for Fe2+ and Fe3+ using 1,10-phenanthroline: III. A rapid photochemical method Clays & Clay Minerals 36 379381 10.1346/CCMN.1988.0360415.CrossRefGoogle Scholar
Lear, P. R. and Stucki, J. W., 1987 Intervalence electron transfer and magnetic exchange in reduced nontronite Clays & Clay Minerals 35 373378 10.1346/CCMN.1987.0350507.CrossRefGoogle Scholar
Lear, P. R. and Stucki, J. W., 1989 Effects of iron oxidation state on the specific surface area of nontronite Clays & Clay Minerals 37 547552 10.1346/CCMN.1989.0370607.CrossRefGoogle Scholar
Monserrate, M. L., 1982 Evaluation of the hydraulic conductivity of two clays exposed to selected electroplating waste Durham, North Carolina Duke University.Google Scholar
Stucki, J. W. and Tessier, D., 1991 Effects of iron oxidation state on the texture and structural order of Na-nontronite gels Clays & Clay Minerals 39 137143 10.1346/CCMN.1991.0390204.CrossRefGoogle Scholar
Stucki, J. W., Golden, D. C. and Roth, C. B., 1984 The preparation and handling of dithionite-reduced smectite suspensions Clays & Clay Minerals 32 191197 10.1346/CCMN.1984.0320306.CrossRefGoogle Scholar
Stucki, J. W., Golden, D. C. and Roth, C. B., 1984 Effects of reduction and reoxidation of structural iron on the surface charge and dissolution of dioctahedral smectites Clays & Clay Minerals 32 350356 10.1346/CCMN.1984.0320502.CrossRefGoogle Scholar
Stucki, J. W., Low, P. F., Roth, C. B. and Golden, D. C., 1984 Effects of oxidation state of octahedral iron on clay swelling Clays & Clay Minerals 32 357362 10.1346/CCMN.1984.0320503.CrossRefGoogle Scholar
Weeks, O. L., 1986 Liner system used for the containment of solvents and solvent-contaminated hazardous wastes .Google Scholar
Wu, J., Low, P. F. and Roth, C. B., 1989 Effects of octahedral-iron reduction and swelling pressure on interlayer distances in Na-nontronite Clays & Clay Minerals 37 211218 10.1346/CCMN.1989.0370303.Google Scholar