EXTRACTIVE PERMEATION OF ZINC(II) AND CADMIUM(II) CHLORIDE COMPLEXES THROUGH ANION-EXCHANGE MEMBRANE

Extractive permeation is demonstrated in the permeation of Zn(II) and Cd(II) chloride complexes through an anion-exchange membrane. A selective permeation between Cd(II) and Zn(II) was observed. This selectivity well corresponded to the sorption selectivity with an anion-exchange resin. Under the large concentration gradient of chloride ions across a membrane, Cd(II) chloride complex was selectively enriched in the receiving solution. The concentration ratios between the source and the receiving solution after 40 h reached 5.8 for Cd(II) and 1.2 for Zn(II) when chloride ions of 0.5 mol dm-3 were added to the source solution.