Abstract
The ability of seventeen different chemical solutions to displace heavy metal ions (Pb, Zn, Cu, Cd), pre-adsorbed on clay (kaolinite, illite and montmorillonite) at either pH 5 or 7, has been examined and the relative efficiency of each extractant ascertained. Of the reagents used, only EDTA (0.001 M, pH 7) quantitatively released all four ions from the three clays; oxalic acid (0.1 M, pH 3.3), totally displaced at least three ions from each clay. Other reagents, for example ammonium oxalate (0.1 M), ammonium nitrate (0.01 M), nitric acid (0.1 M) and sodium citrate (0.01 M) effectively displaced one or more heavy metal ions from individual clays. Near quantitative displacement by an excess of Na (0.1 M) or Ca (0.05 M) ions was observed only on montmorillonite. Pre-adsorption at pH 7 was accompanied by precipitation of excess metal ion, and the extraction efficiency in these systems was determined by the ability of the reagent to both dissolve hydrous oxide species and displace sorbed metal ions.
The implications of the results with respect to the nature of the adsorption process and relevance to environmental systems have been considered.
Similar content being viewed by others
References
Farrah, H. and Pickering, W. F.: 1976, Aust. J. Chem. 29, 1167, 1177.
Farrah, H. and Pickering, W. F.: 1976, Aust. J. Chem. 29, 1649.
Farrah, H. and Pickering, W. F.: 1977, Aust. J. Chem. 30, 1417.
Farrah, H. and Pickering, W. F.: 1977, Water Air Soil Pollut. 8, 189.
Hodgson, J. F.: 1960, Soil Sci. Soc. Am. Proc. 24, 165.
Elgabaly, M. M.: 1950, Soil Sci. 69, 167.
Maes, A. and Cremers, A.: 1975, Soil Sci. 119, 198.
Hildebrand, E. E. and Blum, W. E.: 1974, Naturwissenshaften 61, 169.
Kishk, F. M. and Hassan, M. N.: 1973, Plant and Soil 39, 497.
Posner, A. M. and Quirk, J. P.: 1964, Proc. R. Soc. London, Ser. A. 278, 35.
El-Sayed, M. H., Burau, R. G., and Babcock, K. L.: 1970, Soil Sci. 110, 197; 1971, Soil Sci. Soc. Am. Proc. 35,571.
McBride, M. M. and Mortland, M. M.: 1974, Soil Sci. Soc. Amer. Proc. 38, 408.
Mishra, P. C., Mishra, M. K., and Misra, S. G.: 1973, Indian J. Agric. Sci. 43, 609.
McLaren, R. G. and Crawford, D. V.: 1973, J. Soil Sci. 24, 172.
Karnaukhov, A. I. and Tkachento, V. M.: 1975, Agrokhimiya 2, 121.
Karamanos, R. E., Beltany, J. R., and Rennie, D. A.: 1976, Can. J. Soil Sci. 56, 37.
Misra, S. G. and Pandey, G.: 1976, Plant Soil 45, 693.
Kobayashi, J., Morii, F. and Muramoto, S.: 1974, Trace Subst. Environ. Health 8, 179.
Norvell, W. A. and Lindsay, W. L.: 1969, Soil Sci. Soc. Amer. Proc. 33, 86; 1970, 36, 778.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Farrah, H., Pickering, W.F. Extraction of heavy metal ions sorbed on clays. Water Air Soil Pollut 9, 491–498 (1978). https://doi.org/10.1007/BF00213544
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00213544