Synthesis and Characterization of a Novel Metal Phosphonate, Zirconium (IV)-Hydroxy Ethylidene Diphosphonate, and Its Application as an Ion Exchanger


Abstract: A novel hybrid ion exchange material, Zirconium-hydroxy ethylidene diphosphonate [ZrHEDP], of the class of tetravalent metal acid (TMA) salts has been synthesized by the sol-gel technique. The material was characterized with elemental analysis (ICP-AES), thermal analysis (TGA, DSC), and FT-IR and X-ray diffraction studies. The chemical resistivity of the material in various media was evaluated. ZrHEDP was further investigated for its possible use as an ion exchanger. The Na^+ ion-exchange capacity (IEC) of the material was determined, and kinetics and thermodynamics of exchange for the metal ions Cu(II), Ni(II), Zn(II), and Mn(II) towards ZrHEDP were studied. The sorption of the metal ions follow the order Zn(II) > Cu(II) > Mn(II) \approx Ni(II).

Keywords: Inorganic ion exchanger, metal phosphonate, tetravalent metal acid salt, zirconium-hydroxy ethylidene diphosphonate, Zr(IV) phosphonate

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