The sorption of copper species by clays. I. Kaolinite

Abstract

The effect of changes in pH and the presence of ligands on the uptake of copper ions by kaolin has been investigated. In alkaline media the clay suspension acts as a nucleation centre for hydroxy-bridged copper species, and the major role of many ligands is to 'mask' this precipitation reaction. Uncharged and negatively charged complex species are not sorbed to any measurable extent. In acidic media, the adsorption capacity of the clay for cationic species increases with pH. Probable mechanisms are discussed and the feasibility of predicting the effects of ligands on sorption considered.