Permselectivity between Cl^- and SO₄^2- in Ion-exchange Transfer

Studies on Ion-exchange Transfer (9)

Abstract

In the present investigation, the authors determined the permselectivity of SO₄^2- and Cl^- through anion-exchange membrane in the ion-exchange transfer by NO₃^-. The results obtained were summarized as follows:
When the concentration ratios of SO₄^2- and Cl^- in the original solution were constant, the transfer rate of SO₄^2- and Cl^- increases, respectively, with an increase in the concentration of NO₃^-, but the ratio of the transfer rate of the both ions was independent of the concentration of NO₃^-.
The permselectivity coefficient of SO₄^2- against Cl^- was very small and approximately equal to that in electrodialysis. This value decreased with an increase in the concentration of the original solution.
Also, the separation factor of SO₄^2- against Cl^- in the anion-exchange membrane showed a decrease with an increase in the concentration of the original solution. This tendency was very similar to that of the permselectivity coefficient.
Thus, it was inferred from the above-mentioned facts that the mobility ratio of SO₄^2- against Cl^-in the membrane could be calculated from the value of the permselectivity coefficient and the separation factor. As the result of our calculation, the value proved to be about 0.5 notwithstanding the concentration of the original solution.