Ion exchange of the rare earths ions Y3+ and La3+ in synthetic mordenite

The exchange of Na+ ions in the mordenite network with Y3+ and La3+ cations of the rare earths was studied. The influence of the exchange solution pH, temperature, the phases contact time, concentration of trivalent ion, nature and concentration of the organic solvent employed on ionic-exchange equilibrium was investigated and the optimum conditions of the saturation of the zeolite were emphasized. On the basis of the exchange isotherms, the apparent equilibrium constants, K, and the proper thermodynamic parameters Delta G, Delta H and Delta S were calculated. The ion exchange takes place in pH = 3-5 solutions, is not complete and it is facilitated by higher temperatures.