Hostname: page-component-76fb5796d-5g6vh Total loading time: 0 Render date: 2024-04-25T09:53:26.430Z Has data issue: false hasContentIssue false

Remediation by artificial cooling of dilute clay suspensions contaminated by heavy metals

Published online by Cambridge University Press:  27 October 2009

G. Gay
Affiliation:
Laboratoire des Matériaux et des Structures du Génie Civil, UMR 113 (CNRS/LCPC), 2 allée Kepler, Cité Descartes, 77420 Champs-sur-Marne, France
M.A. Azouni
Affiliation:
Laboratoire des Matériaux et des Structures du Génie Civil, UMR 113 (CNRS/LCPC), 2 allée Kepler, Cité Descartes, 77420 Champs-sur-Marne, France

Abstract

Vertical freezing of clayey suspensions contaminated by heavy metals was conducted. A small unidirectional thermal gradient applied to a sample placed in a parallelopipedic cell led to the low-rate propagation of an upward freezing front. During this propagation, segregation of salts occurred and the non-solidified phase ahead of the freezing front became enriched with metallic salts. Moreover, some of the non-miscible particles in suspension were repelled by the freezing front. Therefore, the solidified phase became poorer with metallic pollutants bound to such nonmiscible particles as clayey colloids or complexes. Thus, artificial cooling was able to purify a suspension contaminated by heavy metals that exist in various chemical forms. This paper presents results for different experimental conditions and physico-chemical parameters such as the pH and the ratio between the concentrations of metallic cations and clay particles. The influence of these physico-chemical parameters on the speciations of lead and on the efficiency of this method is discussed. These freezing tests carried out on polluted soils should succeed in their remediation. This new method is called ‘cryoremediation’.

Type
Articles
Copyright
Copyright © Cambridge University Press 2001

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

Andersland, O.B., Wiggert, D.C., and Lehner, C.A.. 1994. Ground water remediation by controlled soil freezing. In: Fremond, M. (editor). Proceedings of the 7th international symposium on ground freezing, Nancy, France. Rotterdam: A.A. Balkema: 5763.Google Scholar
Azouni, M.A., and Casses, P.. 1998. Thermophysical properties effects on segregation during solidification. Advances in Colloid and Interface Science 75: 83106.CrossRefGoogle Scholar
Brovka, G.P. 1999. A theoretical consideration of the migration of radionuclides in frozen grounds. Colloid Journal 61 (6): 696700.Google Scholar
Chalmers, B. 1964. Principles of solidification. London: John Wiley and Sons.Google Scholar
Chuvilin, E.M. 1999. Migration of ions of chemical elements in freezing and frozen soils. Polar Record 35 (192): 5966.CrossRefGoogle Scholar
Corte, A.E., 1962. Vertical migration of particles in front of a moving freezing plane. Journal of Geophysical Research 67 (3): 10851090.Google Scholar
Dash, J.G., Fu, H.Y., and Leger, R.. 1997. Frozen soil barriers for hazardous waste confinement. In: Knutsson, S. (editor). Proceedings of the international symposium on ground freezing and frost action in soils, Luleå, Sweden. Rotterdam: A.A. Balkema: 375380.Google Scholar
Evans, L.J. 1989. Chemistry of metal retention by soils. Environmental Science and Technology 23 (9): 10461056.Google Scholar
Gao, W., Smith, D.W., and Sego, D.C.. 1999. Ice nucleation in industrial wastewater. Cold Regions Science and Technology 29: 121133.Google Scholar
Gay, G., and Azouni, A.. 1998. An approach of soils cryoremediation. In: Proceedings of the conference on permafrost and actions of natural or artificial cooling, Orsay, France. Paris: International Institute of Refrigeration: 217224.Google Scholar
Gay, G. and Azouni, A.. 2000. Forced migration of heavy metals ahead of a solid-liquid interface. In: Gamier, J., Thorel, L., and Haza, E. (editors). Proceedings of the international symposium on physical modelling and testing in environmentalgeotechnics, La Baule, France. Paris: LCPC: 6975.Google Scholar
Holtz, R.D., Kovacs, W.D., and Lafleur, J.. 1991. Introduction à la géotechnique. Paris: Lavoisier.Google Scholar
Hung, W.T., Feng, W.H., Tsai, I.H., Lee, D.J., and Hong, S.G.. 1997. Uni-directional freezing of waste activated sludges: vertical freezing versus radial freezing. Water Research 31 (9): 22192228.Google Scholar
Lecomte, P. 1998. Les sites pollués: traitement des sols et deseauxsouterraines. Second edition. Paris: Lavoisier.Google Scholar
Luckham, P.F., and Rossi, S.. 1999. The colloidal and Theological properties of bentonite suspensions. Advances in Colloid and Interface Science 82: 4392.CrossRefGoogle Scholar
Martel, C.J., Affleck, R., and Yushak, M.. 1998. Operational parameters for mechanical freezing of alum sludge. Water Research 32 (9): 26462654.Google Scholar
Martel, C.J., Affleck, R.T., and Yushak, M.L.. 1996. A device for mechanical freeze–thaw conditioning of alum sludge. Hanover, NH: Cold Regions Research and Engineering Laboratory (CRREL report 96–15).Google Scholar
Mohamed, A.M.O., Yong, R.N., and Mazus, M.T.. 1995. Contaminant migration in engineered clay barriers due to heat and moisture redistribution under freezing conditions. Canadian Geotechnical Journal 32: 4059.CrossRefGoogle Scholar
Parker, P.J., and Collins, A.G.. 1999. Ultra-rapid freezing of water treatment residuals. Water Research 33 (10): 22392246.CrossRefGoogle Scholar
Ravaska, O., and Kujala, K.. 1997. Freeze-thaw effect on soil-bentonite mixtures. In: Knutsson, S. (editor). Proceedings of the international symposium on ground freezing and frost action in soils, Luleå, Sweden. Rotterdam: A.A. Balkema: 147152.Google Scholar
Shirai, Y., Wakisaka, M., Miyawaki, O., and Sakashita, S.. 1999. Effect of seed ice on formation of tube ice with high purity for a freeze wastewater treatment system with a bubble-flow circulator. Water Research 33 (5): 13251329.CrossRefGoogle Scholar
Tiller, W.A. 1963. Principles of solidification. In: Gilman, J.J. (editor). The art and science of growing crystals. New York: John Wiley and Sons: 276312.Google Scholar
Yong, R.N., Mohammed, A.M.O., and Warkentin, B.P.. 1992. Contaminant–soil interaction. In: Principles of contaminant transport in soils. Amsterdam: Elsevier (Developments in geotechnical engineering 73): 143180.Google Scholar