Study of ion transport across amphoteric ion-exchange membrane. V: Nonequilibrium thermodynamic analyses of ion selectivity

Ion-transport processes across an amphoteric ion-exchange membrane were investigated by means of estimating the membrane permeability matrix, a set of modified linear phenomenological coefficients, from the electrochemical and the ion flux data. Systematic comparisons of phenomenological analyses on an amphoteric ion-exchange membrane system with those on an ordinary cation-exchange membrane system were carried out to investigate the correlations of singly- and binary-charged membrane structures to characteristic transport properties. The modes of ion permselectivity of an amphoteric ion-exchange membrane in the metal chloride concentration-cell systems are characterized by the potentiometric selective response due to the ion-sieve effect, the low membrane conductance, and the large ion flux, while those of an ordinary cation-exchange membrane are characterized by the totally charge-dependent potential response, the high conductance, and the extremely small ion flux. The cross elements of the membrane per...