Synthesis, Characterization and Thermodynamics of Exchange Using Zirconium Titanium Phosphate Cation Exchanger

Abstract

A mixed material of the class of tetravalent bimetallic acid (TBMA) salt - zirconium titanium phosphate (ZTP) - has been synthesized by the sol-gel technique. ZTP has been characterized by elemental analysis, thermal analysis (TGA, DTA), FTIR, X-ray diffraction and SEM. Ion exchange capacity (IEC) of the material has been determined and the effect of calcination (373-773 K) on IEC studied and chemical stability of the material in various media (acids, bases and organic solvents) assessed. Further, the equilibrium exchange of H in ZTP for Mg2+, Ca2+, Sr2+ and Ba2+ ions has been studied at 303, 313, 323 and 333 K at constant ionic strength. On the basis of the exchange isotherms, various thermodynamic parameters such as equilibrium constant (K), standard gibbs energy change (∆Go), entropy change (∆So) and enthalpy change (∆Ho) have been calculated. The parameters were correlated with the ion exchange characteristics of the material.