Electrotransport of Cr(VI) through an anion exchange membrane

The electrotransport of Cr(VI) oxo anions through an anion exchange membran e (AEM) is investigated as functions of the CrO3 concentration and pH on bo th sides of the membrane. This transport strongly depends on the polychroma te ion formation within the membrane, which is favoured by both the very hi gh concentration compared to that of the bulk solution and the proton leaka ge usually encountered when an AEM is in contact with acid solutions. Their formation is closely connected to the pH of the donor compartment of the e lectrodialysis cell. Their presence can lead to an inversion of the AEM per mselectivity. The increase of the transport number of Cr(VI) species is ass ociated with the reduction of the proton leakage. (C) 2000 Elsevier Science B.V. All rights reserved.