Synthesis, characterisation and ion exchange properties of zirconium(IV) tungstophosphate, a cation exchanger

Eight samples of the three-component cation exchanger zirconium(IV) tungstophosphate (ZWP) were prepared under varying conditions of mixing, ratio of solutions of 0.1 M zirconium oxychloride, 0.1 M sodium tungstate, 0.1 M ammonium sodium hydrogenorthophosphate and 0.1 M orthophosphoric acid, pH values and others. The material shows ion exchange capacity for K+ ions of 1.00 meq/g. Its chemical composition was found to have Zr(18.90%), W(25.40%) and P(4.30%) and its chemical dissolution was also determined and compared with Sn(IV) tungstophosphate and Zr(IV) selenophosphate. It has been characterised by X-ray, IR, TGA and SEM analysis. A number of ion exchange studies like pH titration, K-d values in demineralised water(DMW), 1 x 10(-5) M HNO3, 1x10(-3) M HNO3, 1x10(-2) M NH4NO3, and in a mixture of 1 x 10(-2) M NH4NO3 and 1 x 10(-2) M HNO3 were studied. On account of the K-d values and elution pattern, the cation exchanger was found to be selective for Pb(II) ions. A number of Pb(II) separations from other metal ions have been successfully achieved.