SOLVENT EFFECT ON THE KINETICS OF THE EXCHANGE OF COPPER IONS ON NA-MONTMORILLONITE

The specific rate coefficients of adsorption of Cu2+ On Na- montmorill onite clay in dimethyl sulfoxide (DMSO) and acetone solvents are deter mined at 20, 30, and 40 degrees C. The reaction is endothermic in natu re. It was found that the E values range from 3.66 kJ mol(-1) in aceto ne to 13.54 kJ mol(-1) in DMSO while at 20 degrees C, the rate constan t k varies from 3.34(ppm)(1-n) per second in DMSO to 16.07 (ppm)(1-n) per second in acetone. The data have been analyzed to obtain activatio n parameters Delta G, Delta H*, and Delta S* for reaction in correspo nding mixtures. A reaction mechanism which describes the copper ion ex change reaction is proposed. (C) 1996 Academic Press, Inc.