Alkali Metal Ion Exchange on Crystalline Zirconium Titanium Phosphate

Abstract

Abstract Ion-exchange studies of crystalline zirconium titanium phosphate with variable zirconium-to-titanium mole ratios have been extended to sodium-ion exchange on the exchangers with Zr-to-Ti mole ratios of 0.37 and 0.61, and to lithium and potassium ion exchange on the exchanger with a Zr-to-Ti mole ratio close to unity. In the sodium-ion exchange, a mono-sodium phase formed up to about a half of the exchange; then a disodium phase with a different amount of water of crystallization formed. In the lithium-ion exchange, the reaction proceeded with the formation of fully exchanged phases whose water content varied depending upon the environment in which the exchanger was placed during or after the reaction. The exchange amount of potassium ions was much less than that of sodium or lithium ions, and the ion exchange proceeded in parallel with an extensive hydrolysis of the exchanger. The half-exchanged phase could not be confirmed in this case. For the three alkali metal ions studied, the selectivity series was found as a function of loading, i.e., within the range of the load from 0 to 1.3 meq/g, the selectivity is in the order of Na+>K+>Li+, between 1.3 and 4.5 meq/g, it is Na+>Li+>K+, and above 4.5 meq/g loading, it turns out to be Li+>Na+>K+.