The removal of metals from aqueous solution using organic extractants adsorbed into clay minerals.

This paper describes the application of a clay mineral, montmorillonite, into which commercial liquid-liquid extraction reagents have been adsorbed. The extraction reagents which have been impregnated include carboxylic and organophosphorous acids as well as chelating acids e.g. Acorga M5640, and Kelex 100. It has been shown that significant amount of these reagents, up to 3.0 moles/kg, can be adsorbed into the clays. These impregnated clays have been used to remove copper and nickel from diluted aqueous solutions. Comparisons will be made between the results obtained by pre-treating the clays to increase the interlayer distance by incorporating metal or alkylammonium cations with those where no pre-treatment occurred. The result show that a significant increase in the metal adsorbed over that expected from the summation of properties expected of the clay and the extractant.