Sorption of potassium on synthetic 4A zeolite from water and water-dimethyl sulphoxide (DMSO) mixtures

Abstract The exchange of Na + and K + ions on 4A zeolite in water and water-DMSO mixtures has been studied at various temperatures and at constant ionic strength (0·10 M). Thermodynamic values for the complete exchange process were calculated. The exchange process is of a complex character. At lower potassium loadings ( n K z K + ion is preferred to Na + ion, and at higher loadings ( n K z >0·3) Na + ion is preferred. With earlier data for the Na + −Li + exchange, the selectivity sequence Na> K >Li was found in both media for the complete process, and the sequence K >Na>Li for the process at n K,Li z