Transport of co-ions across ion exchange membranes in electrodialytic metathesis MgSO4 + 2KCl → K2SO4 + MgCl2

Flow rates of co-ions across membranes (Cl− and SO42− ions across Neosepta CMX cation exchange membranes, K+ and Mg2+ ions across Neosepta AMX anion exchange membranes) in the title electrodialytic metathesis have been determined. It was established that the flow of co-ions causes contamination of all solutions flowing through the electrodialyzer. For instance, Cl− ions penetrate into anolyte (K2SO4 solution), chlorine is found among anode reaction products and deteriorates operating conditions and induces corrosive processes. A quantitative contamination assessment of two products (potassium sulphate and sodium chloride) was carried out.