Studies with Inorganic Ion-exchange Membranes. I. Effect of Binding Material on the Permeation of Electrolyte Solutions across Titanium Tungstoarsenate Membranes

Abstract

Abstract A comparative study of permeability for various electrolytes is made on parchment-, polystyrene-, and Araldite based membranes of titanium tungstoarsenate at 20, 25, 30, and 35 °C. At any given temperature the order of permeability increase is K+>Na+>Li+ for 1:1 electrolytes and Ba2+>Ca2+>Mg2+ for 2:1 electrolytes. Permeability values are higher for parchment-based than polystyrene-based membranes. The diffusion of these electrolyte solutions across Araldite based membrane is almost negligible. Thermodynamic parameters of diffusion process, viz., ΔH≠, ΔS≠, ΔF≠ have been evaluated at 25 °C by applying the theory of absolute reaction rates. ΔS≠ values are negative for all the cations for both the membranes except that of Li+ which is positive for parchment-based membranes. ΔF≠ values are higher for the polystyrene-based than parchment-based membranes.