Copper (II) interaction with kaolinite facotrs controlling adsorption

Abstract--The adsorption fCu *+ on kaolinite was studied at different ionic strengths following various treatments of the mineral surface in order to evaluate he conditions influencing adsorption. The data indicate astrong preference of the Na + exchange form of kaolinite for Cu z+ but a weak affinity of the natural kaolinite for Cu ~+. Protons are generated by Cu 2+ adsorption, a result of the exchange ofsurface protons, and possibly the enhancement of Cu 2+ hydrolysis at the kaolinite surfaces. The exchange ofNa + by Cu z+ on the kaolinite isnot described by the mass-action equation, but can be interpreted in terms of permanent charge sites on the surfaces when the additional factors of Na+-H30 +exchange and blockage of sites by AI ions are considered. Key Words---Adsorption, Copper, Exchange, Hydrolysis, Kaolinite