Determination of Cu2+ in aqueous solution using a polyindole–tin(IV) molybdophosphate conductive nanocomposite ion-selective membrane electrode.

Abstract Polyindole–tin (IV) molybdophosphate (PIn-SMP), an organic-inorganic nanocomposite ion exchanger, was synthesized by a sol-gel process and exhibited excellent ion exchange capacity (2.1 meq g−1). A heterogeneous ion exchange membrane of PIn-SMP (ion exchange capacity 0.95 meq g−1) was also prepared by a solution casting method. The materials were characterized by various instrumental methods, such as scanning electron microscopy, transmission electron microscopy, Fourier transform IR spectroscopy, and thermogravimetric analysis. PIn-SMP exhibits high electrical conductivity (6.1 × 10−2 S/cm) and is stable up to 120 °C under ambient conditions. A Cu2+-selective membrane electrode was fabricated, and its linear working range (1.8 × 10−7–1.0 × 10−1 M), response time (20 s), Nernstian slope (24.07 mV dec−1), and working pH range (4–7) were calculated. Moreover, it was used as an indicator electrode in the potentiometric titration of Cu2+. Graphical abstract Image 1 Highlights • Polyindole–tin (IV) molybdophosphate nanocomposite ion exchanger (IEC-2.1 meq g−1), was synthesized by a sol-gel process. • The nanocomposite displayed high DC electrical conductivity (6.1 × 10−2 S cm−1) at room temperature. • A heterogeneous ion exchange membrane (IEC-0.95 meq g−1) was prepared by a solution casting method. • The materials were characterized by various instrumental methods, such as SEM, TEM, FT-IR, and TGA analysis. • A Cu2+-selective membrane electrode was fabricated and exhibited a wide linear response range (1.8 × 10−7–1.0 × 10−1 M). [ABSTRACT FROM AUTHOR]