Synthesis, characterization and thermodynamics of exchange using zirconium titanium phosphate cation exchanger

sA 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 (Delta G(O)), entropy change (Delta S-O) and enthalpy change (Delta H-O) have been calculated. The parameters were correlated with the ion exchange characteristics of the material.