FACTORS DETERMINING ION-EXCHANGE SELECTIVITY .2. THE ELECTROSTATIC EFFECT AS DETERMINED FROM GAS SOLID REACTIONS

The magnitude of the electrostatic effect in ion exchange was determined by measuring the free energy of the reaction Zr(MPO4)2(s) + xHCl(g) ZrM2-xHx(PO4)2(s) + xMCl(s) where M = Li+, Na+, K+. The free energies so determined were extrapolated to 25C and converted to free energies of the reactions Zr(MPO4)2(s) + H+(g) ZrMH(PO4)2 + M+(g) and ZrMH(PO4)2(s) + H+(g) Zr(HPO4)2 + M+(g) by means of a thermodynamic cycle. The selectivity was in the order H+ > Li+ > Na+ > K+ as predicted by Eisenman's theory. The sequence is largely determined by the differences in free energies of vaporization and ionization of the alkali metals. 1983 American Chemical Society.

FACTORS DETERMINING ION-EXCHANGE SELECTIVITY .2. THE ELECTROSTATIC EFFECT AS DETERMINED FROM GAS SOLID REACTIONS Academic Article