Potentiometric Determination of Nickel (II) Ion Using Zirconium (IV) Antimono Tungstate as an Electroactive Material

Abstract

Aims: The research work is based on the fabrication of ion selective Electrode based on Zirconium (IV) antimono tungstate. Study Design: The Study was designed to make ion selective electrode for transition metal ions. Place and Duration of Study: Department of Chemistry, M M. University, Mullana (Ambala). It can be used for five months i.e Jan - May 2013, with a good reproducibility. Methodology: Zirconium (IV) antimono tungstate having ion exchange capacity of 0.30 meq g-1 for Na+ ion was synthesized by sol –gel method and characterized by physicochemical techniques. The proposed electrode was prepared by mixing the ionophore with the required amount of epoxy resin. Then potentiometric studies were carried out. Results: Epoxy-based membrane of zirconium (IV) antimono tungstate (50% ZrSbW and 50% epoxy resin) reveals a sub-Nernstian potentiometric response with the slope of 20 mV per decade for Ni2+ over a wide concentration range (10−6 to 10−1 M). The response time of the electrode is quite low and could be used for a period of 5 months with a good reproducibility. The proposed electrode reveals very high selectivity for Ni2+ in the presence of a wide variety of metal ions such as Zn2+,  Pb2+, Cd2+, Cu2+, Ce3+, Na+, Ca2+, Mg2+, Pr3+ Y3+ and Fe3+ at concentrations 1×10−3 M and 1×10−4 M. Effect of internal solution concentration was studied. The proposed sensor can be used in the pH range of 2.90 - 9.20. It was used as an indicator electrode in the potentiometric titration of Ni2+ ions against EDTA. Conclusion: Zirconium (IV) antimono tungstate can be successfully used as electro-active material for making a nickel (II)-selective membrane electrode. The proposed electrodes have reasonably good lifetime, detection limit, pH range and selectivity coefficient. They can also be used as indicator electrodes for trace level determination of Nickel ions.