1986 Volume 12 Issue 4 Pages 453-458
Sorption equilibria, apparent diffusivities and activation energies of diffusion were measured for four acids (hydrochloric acid, sulfuric acid, oxalic acid and phosphoric acid) in the anion-exchange membrane SELEMION-AMV. The sorption-equilibrium data were simulated on the basis of the Donnan theory with the ratio of activity coefficient of chloride ion insolution to that in membrane for hydrochloric acid, and the selectivity coefficients KHSO4SO4, KHC2O4C2O4 and KH2PO4HPO4 for polybasic acids, as parameters. The differential diffusivities of acids were determined in membrane as a function of hydrogen concentration in the membrane based on the sorption-equilibrium data and the apparent diffusivities.
The results indicate that the anion-exchange membrane uptakes HSO4-and HC2O4-selectively and that the differential diffusivity of each acid becomes large with increasing hydrogen concentration in the membrane. The activation energy for polybasic acid tended to increase with increasing concentration in the strip solution, and was independent of the concentration in the feed solution.
