Hydrolytic stability of amorphous titanium and zirconium phosphates

Spherically granulated amorphous titanium and zirconium hydroxophosphates, Ti(OH)P and Zr(OH)P, with different molar P:M(IV) ratio varying in a range of (0.51.1):1, have been synthesized and their hydrolytic behavior has been studied as a function of the chemical composition of the material, type of exchanger's salt form, pH and concentration of electrolyte, type of electrolyte, temperature of model solution and some other factors. It was found that the hydrolysis of Ti(OH)P and Zr(OH)P in neutral and alkaline media is a complex process occurring by nucleophilic mechanism of phosphate group substitution. The governing factors are steric hindrances for nucleophilic attack and the value of the effective positive charge on titanium and zirconium atoms.