Transport of Trivalent and Hexavalent Chromium through Different Ion-Selective Membranes in Acidic Aqueous Media

Abstract

The aim of this work was to evaluate the transport of trivalent and hexavalent chromium through anion- and cation-selective membranes using two-and three-compartment electrodialysis cells. Tests were done with acidic solutions of trivalent chromium ions, Cr³+, and hexavalent chromium ions, Cr₂O² ₇. In each situation the transport of metallic ions through the membrane was evaluated. In the tests with trivalent chromium, Nafion 417 and Selemion CMT cation-selective membranes were used, and in the tests with hexavalent chromium, Selemion AMT membrane was used. The influence of SO² ₄ ions and of the concentration of H⁺ ions in the solutions was also analyzed. Results showed the oxidation of the Cr³* ion at the anode and the reduction of the Cr² ₇; ion at the cathode. The maximum yield in the process was reached when hexavalent chromium solutions were used in the absence of sulfate ions and a Selemion AMT membrane in a three-compartment cell.