EFFECT OF IONIC CHARGE ON THE ELECTRICAL-PROPERTIES OF AN AMPHOTERIC ION-EXCHANGE MEMBRANE

In order to clarify the mechanism of ion transport across an amphoteric membrane with sulfonate and N-methylpyridinium groups as exchange sites, membrane potential and membrane conductance measurements were carried out with varying valences of cations and anions of the electrolyte solution. It was shown that the membrane studied behaves as a cation exchange membrane in 1-1 valent and 2-2 valent electrolyte solutions. On the other hand, the membrane function was strongly influenced by the valence of the cation; the membrane in the LaCl//3 system in particular was preferentially anion selective. The permeability coefficients were evaluated according to the theory of nonequilibrium thermodynamics, and ion transport was discussed.