Chronopotentiometric and electroanalytical studies of Ni(II) selective polyaniline Zr(IV) molybdophosphate ion exchange membrane electrode

• Application of PAZMP membrane to fabricate Ni(II) ion selective electrode.
• Preparation and characterization have also been done of ion exchange membrane.
• Determination of liner potential response with concentration range of 1 × 10−7 M–1 × 10−1 M.
• Chronopotentiometric studies of membrane were evaluated by Nernst-Planck equation.
• Some physical parameters such as D0, Ea and ΔS° were calculated.

Polyaniline Zr(IV) molybdophosphate (PAZMP) was synthesized by sol–gel method and its ion exchange capacity (IEC) was determined as 2.50 meqg−1. On the basis of distribution co-efficient (Kd values) the material was selective for Ni(II). The Ni(II) selective membrane was prepared (IEC 0.65 meqg−1) to fabricate Ni(II) selective membrane electrode with its linear potential response in the concentration range of 1 × 10−7 M–1 × 10−1 M. The morphology and composition of the prepared PAZMP membrane were ascertained by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) respectively. The ion exchange mechanism through membrane was determined by chronopotentiometric studies using Nernst-Planck equation at 30 °C, 45 °C and 60 °C. As a result physical parameters such as self-diffusion coefficient (D0), energy of activation (Ea) and entropy of activation (ΔS°) were calculated. The analytical utility of this electrode was established by employing it as an indicator electrode in potentiometric titration.

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