ION-EXCHANGE KINETICS OF ALKALINE-EARTH METALS ON ZIRCONIUM(IV) PHOSPHOANTIMONATE CATION-EXCHANGER - ENERGY AND ENTROPY OF ACTIVATION AS A LINEAR FUNCTION OF IONIC MOBILITIES AND RADII

The Nernst-Planck equations have been applied to study the ion exchange kinetics on the surface of zirconium(Iv) phosphoantimonate for Mg2+ - H+, Ca2+ - H+, Sr2+ - H+ and Ba2+ - H+ exchanges under conditions favouring a particle diffusion phenomenon. Various kinetic parameters, such as self-diffusion coefficient (D-o), energy of activation (E(a)) and entropy of activation (Delta S*) have been evaluated. The energy and entropy of activation vary linearly with the ionic radii and mobilities.