Competitive transport of hydrochloric acid and zinc chloride has been investigated in a two-compartment mixed cell with an anion-exchange membrane Neosepta-AFN developed and produced by Tokuyama Soda Co. These experiments have proved that hydrochloric acid permeates well through the membrane used but, on the other hand, zinc chloride is not effectively rejected. The flux of zinc chloride has been found to be increasing with increasing acid and salt concentrations. Furthermore, it has been found that it is approximately one order of magnitude higher than that found in the case of simultaneous transport of sulfuric acid and zinc sulfate through the same membrane. The further calculations concerning the ionic equilibria with sorption isotherms for the HCl-ZnCl, system, which have been measured experimentally, have revealed that high flux of ZnCl, is due to the fact that a considerable amount of zinc chloride in the membrane is in the form of ZnCl complex, which is relatively small and passes well through this membrane. (c) 2006 Wiley Periodicals, Inc.