KINETICS AND THERMODYNAMIC PARAMETERS OF THE COPPER EXCHANGE ON NA-MONTMORILLONITE CLAY MINERAL IN SELECTED SOLVENTS

The kinetics of Cu ion exchange on Na-montmorillonite clay mineral has been investigated at three temperatures, in three solvents: H2O, ethy lene glycol and glycerol. Solvent effects on the reaction rate have be en discussed. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. The determined isokinetic temperature indicates that the reaction is enthalpy controlled where the interaction between solvent and clay surface plays an important ro le. A reaction mechanism which describes the solvent effect on the rat e of Cu ion exchange is proposed.