Sorption and ion exchange behavior of Pb(Ⅱ) , Bi(Ⅲ) and Th(Ⅳ) in aqueous solutions towards zirconium phosphate

摘要

Amorphous zirconium phosphate (ZP), an inorganic ion exchanger of the class of tetravalent metal acid (TMA) salt, has been synthesized by sol-gel method, and characterized by elemental analysis (ICP-AES), thermal analysis (TGA, DSC), FT-IR and X-ray diffraction studies. Sorption/ion exchange behavior of metal ions [Pb(Ⅱ), Bi(Ⅲ) and Th(Ⅳ)] towards ZP has been studied varying temperature, kinetic (over all rate constant k2 and equilibrium constant k_c,) and thermodynamic parameters (standard free energy ΔG°, enthalpy ΔH°,and entropy ΔS°) evaluated and adsorption isotherms (Langmuir and Fruendlich) studied. Sorption of metal ions follows the order Pb(Ⅱ) > Bi(Ⅲ) > Th(Ⅳ).