Active and Selective Transport of Alkali Metal Ions through the Macromolecular Complex Membrane Consisting of “Polyaluminium Chloride” and Poly (potassium vinyl sulfate)

Abstract

Macromolecular complex (MC) consisting of “polyaluminium chloride” (PAC) and poly(potassium vinyl sulfate) (PVSK) was prepared by dropping PAC to PVSK solution at pH 1.0, and a membrane was casted from 1, 4-dioxane-hydrochloric acid solution to obtain a stable MC membrane against acid and alkaline solutions. The transport ratio of Na+and the electric potential difference between left and right sides of the membrane were measured. As the results, the transport ratio was high when the electric potential difference was large and was maintained for a long time. From the result, it was revealed that the driving force of transport depends on the membrane potential such as a Donnan potential and diffusion potential between both sides of the membrane. The membrane potential difference was decreased rapidly by Cl^- permeation from the acid side to the alkaline side. In addition, the transport ratio of Na⁺ and the membrane potential difference were also measured in the case that poly(styrenesulfonate) ion was used as a counter ion and compared with those in the case of HCl. On the other hand, K⁺ was transport more rapidly than Na⁺ in the selective transport. The selective transport was controlled by the radius of hydrated alkali metal ions and the affinity of carrier in the membrane for those ions. The MC membrane consisting of PAC as inorganic macromolecule and PVSK was compared with that constituted of glycol chitosan as organic macromolecule and PVSK for the differences of characteristics.