A novel, integrated treatment system for coal wastewaters. Quarterly report, September 2, 1991--December 1, 1991

Abstract

This is the first quarterly report of the above project. The aims of this study are to develop, characterize and optimize a novel treatment scheme that would be effective simultaneously against the toxic organics and the inorganics present in coal conversion wastewaters. The initial phase of the work has been focused on the development of modified clays for use in the selective removal and recovery of heavy metals such as Cd, Cu, chromate and selenate. The results presented here show that a surfactant-modified clay adsorbs Cd strongly at a pH of 8.5 and poorly at pH 4.0. Further, the adsorption of Cd on modified clay is unaffected by the ionic strength of the medium. In the case of Cu, it has been shown that the metal forms a complex with alkyl diamines in aqueous solutions at a pH of 6.0 and does not bind to these surfactants at a lower pH of 3.0. These findings are a preliminary indication that the surface and solution chemistry of amine surfactants can be gainfully modified to adsorb and desorb cationic heavy metals.