Ion-Exchange Equilibria of Transition Metals and Potassium Ions on an Inorganic Ion-Exchanger: Zirconium(IV) Iodophosphate

The ion-exchange equilibria of various divalent transition metal ion (Co 2+ , Zn 2+ , Cd 2+ and Cu 2+ )/K + systems have been studied over the temperature range 30–60°C on zirconium(IV) iodophosphate (ZIP). The exchange isotherms were constructed by means of a batch technique for M(NO 3 ) 2 /KNO 3 media of 0.01 mol/kg ionic strength, where M = Co 2+ , Zn 2+ , Cd 2+ or Cu 2+ . The selectivity sequence was determined as Co 2+ < Zn 2+ < Cd 2+ < Cu 2+ . Thermodynamic equilibrium constants and values of ΔG 0 , ΔS 0 and ΔH 0 were evaluated for the exchange process.