Fabrication of electrically conductive membrane electrode of gelatin-tin (IV) phosphate nanocomposite for the detection of cobalt (II) ions

Gelatin-tin (IV) phosphate nanocomposite (GT/TPNC) ion exchanger was synthesized by mixing gelatin gel into the precipitates of tin (IV) phosphate using sol–gel method. GT/TPNC was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ion exchange capacity of GT/TPNC was reported to be1.44?meq/g. The material was found monofunctional as indicated from pH titration curves. The distribution coefficient of different metal ions such as Zn²⁺ (42.10), Cd²⁺ (37.93), Mg²⁺ (33.33), Cu²⁺ (33.21), Al³⁺ (14.28), Pb²⁺ (6.06), Ni²⁺ (12.50) and Co²⁺ (50.0) was studied using GT/TPNC ion exchanger. The distribution studies confirmed the selectivity of GT/TPNC for Co (II). The photocatalytical degradation of MB was found to be 78% within 5 h of solar illumination using GT/TPNC. Some binary separations such as Co²⁺–Pb²⁺, Cd²⁺–Ni²⁺, Co²⁺–Mg²⁺, Mg²⁺–Zn²⁺, Pb²⁺–Zn²⁺, Cu²⁺–Al³⁺, Al³⁺–Cd²⁺, Ni²⁺–Cu²⁺ were attempted using GT/TPNC ion exchanger. GT/TPNC was explored for the fabrication of ion-sensitive membrane electrode for the determination of Co (II) in the water system. The membrane electrode was found mechanically more stable with quick response time (30?s) and a wide pH working range (4.0–7.0).