Transport Properties of Cation-Exchange Membrane–Aqueous Electrolyte System

Abstract

Abstract Transport properties of a cation-exchange membrane-aqueous sodium chloride solution system have been studied. The membrane used was a sulfonated styrene–divinyl benzene copolymer, Neosepta C66-5T. The salt concentration was kept at 10−1 mol dm−3 on one side of the membrane and varied from 10−3 to 10−2 mol dm−3 on the other. The six elements of a conductance matrix have been experimentally determined according to the previous theory and the membrane properties were discussed in terms of conductance elements. All the elements of the conductance matrix were positive within the concentration range studied. This would be characteristic of a cation-exchange membrane. The electrical ion conductance was greater than the diffusional ion conductance by a factor of 10 to 100. The ion-solvent coupling coefficient was much less than the interionic one, although the electroosmotic conductance was ten-times greater than the membrane conductance. The reflection coefficient was close to unity. The electroosmotic properties were also discussed in terms of the conductance matrix.