Synthesis, characterization and properties of polystyrene incorporated calcium tungstate membrane and studies of its physicochemical and transport behavior

This article reports the synthesis of an inorganic nanocomposite material blended with an organic binder by sol–gel method which has been applied as a potential membrane system. The prepared hybrid compound has been extensively characterized by TG–DTA, SEM and FTIR. The XRD study reveals that the polycrystalline nanocomposite is composed of small crystals with an average granular size of 15.8 nm. Ion-exchange capacity, water content and volume void porosity of the composite were determined in order to study the physicochemical properties of the membrane. The values of potentials measured across the polystyrene blended calcium tungstate membrane, using various uni-univalent electrolytes (aqueous KCl, NaCl, LiCl and NH4Cl solutions), were used to evaluate the fixed charge density using different approaches on the basis of irreversible thermodynamics. The counter-ion transport number, mobility ratio and permselectivity of the tungstate membrane were figured out and were found to follow the order Li + > NH 4 + > K + > Na + i.e. the inorganic–organic hybrid membrane is more cation selective towards Li+ ions for the same electrolytic concentration.