SOME ISSUES IN THE THERMODYNAMICS OF ION EXCHANGE OF TRANSITION AND RAREEARTH METALS ON Na-CLINOPTILOLITE

This article presents calculations of the thermodynamic constants of ion-exchange equilibria for Cu²⁺, Co²⁺, Ni²⁺, La³⁺, and Ce³⁺ ions on a sorbent prepared from the Na form of the natural zeolite clinoptilolite, using the equations of A. M. Tolmachev and V. I. Gorshkov. These equations describe bulk processes and relate the amount of sorption to the activity or concentration in solution. The Gibbs free-energy change and other thermodynamic parameters were calculated from these data.