Removal of Nickel and Cobalt from Aqueous Solutions by Na-Activated Bentonite
The ability of Na-activated bentonite to remove Ni2+ and Co2+ from aqueous solutions at room temperature (22 ± 1°C) was studied under various experimental conditions. The parameters studied were solid-to-liquid ratios and initial cation concentrations. Experiments involved the behavior of bentonite vs. Ni and Co separately and where Ni and Co were present in solution at different concentrations and ratios. Bentonite retained substantial amounts of both metals readily, but it showed a higher affinity for Ni. Over-exchange appears when initial metal concentration exceeds the concentration corresponding to the cation exchange capacity (CEC) of bentonite. The presence of both metals in solution may be either synergistic or antagonistic sorption, depending on the initial ion concentrations.
Key WordsAdsorption Bentonite Cation Exchange Clays Cobalt Removal Heavy Metals Nickel Removal Wastewater
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- Baes, C.F. and Mesmer, R.E. (1976) The Hydrolysis of Cations. Wiley-Interscience Publications, John Wiley & Sons, New York, 238–247.Google Scholar
- Gregg, S.J. and Sing, K.S.W. (1982) Adsorption, Surface Area and Porosity. Academic Press, Inc., London, 5–49.Google Scholar
- Loizidou, M. and Townsend, R.P. (1987) Exchange of cadmium into the sodium and ammonium forms of the natural zeolites, clinoptinolite, mordenite and ferrierite. Journal of the Chemical Society Dalton Transactions, 1991–1996.Google Scholar
- van Olphen, H. (1977) An Introduction to Clay Colloid Chemistry, 2nd edition, John Wiley & Sons Inc., New York, 258–259.Google Scholar