Selective removal of lead (II) ions and estimation of Ca (II) ions using poly-o-toluidine–zirconium (IV) molybdophosphate

Abstract

A new composite cation exchange material poly-o-toluidine–zirconium (IV) molybdophosphate (PTD–ZrMoP) was synthesized by sol–gel method through the incorporation of inorganic gel of zirconium(IV) molybdophosphate in the organic polymer poly-o-toluidine. The PTD–ZrMoP was characterized by FTIR, FESEM, HRTEM, XRD and TGA/DTA techniques. Elution behavior, thermal stability, pH titrations, chemical stability, distribution studies and quantitative separation of metal ions in binary synthetic mixtures and real life samples on nanocomposite ion exchanger were also investigated. The ion-exchange capacity of the nanocomposite ion exchanger (0.84 meq/g) has been observed to be higher compared to that of its inorganic counterpart (0.49 meq/g). The nanocomposite was found to be thermally stable and retained 71.43% of its ion-exchange capacity up to 300 °C temperature. The environmental applicability of the PTD–ZrMoP nanocomposite was explored by achieving binary separations and selective separation of Pb2+ from synthetic mixtures of metal ions. The analytical utility of nanocomposite ion exchanger has been established by the separation of harmful Pb2+ ions from waste water samples obtained from paint industry, textile industry and lead storage battery unit, and by the quantitative estimation of Ca2+ ions in a commercially available pharmaceutical formula.