A nanostructured inorganic-organic composite membrane has been synthesized by cost effective sol-gel method under acidic conditions. Membrane potential measurements have been carried out in various monovalent electrolytes (KCl (aq), NaCl (aq), etc.) at different concentrations to scrutinize the relationship between fixed charge concentration and electrochemical properties of the membrane. Effective fixed charge densities are found to follow the order: Li+ > NH4+ > K+ > Na+. The calculated values of permselectivity, ionic mobility ratio and counter-ion transport number reveal that the inorganic-organic nanocomposite membrane is more cation-selective towards Li+ ions; however the selectivity decreases with the increase in concentration for all monovalent electrolytes used. These membranes were comprehensively characterized for their physicochemical properties, morphology, molecular interactions, crystallinity and thermal stability by various analyses. The ion-exchange capacity, volume void porosity and water uptake of the membrane are found to be highly dependent on polystyrene content in the membrane phase and these properties decrease with the increase in the amount of polystyrene. Furthermore, membrane with 25% blend ratio with polystyrene is found to exhibit good selectivity along with moderate ion-exchange capacity, which may be used for their application in electro-driven separation at high temperatures or for other electrochemical processes. (C) 2013 Elsevier B.V. All rights reserved.