PREFERENTIAL TRANSPORT OF NICKEL AND CUPRIC IONS THROUGH CATION-EXCHANGE MEMBRANE IN ELECTRODIALYSIS WITH A COMPLEX AGENT

The preferential transport of nickel and cupric ions through cation exchange membranes was studied with electrodialysis in chloride solutions containing a complex agent. Citric acid and glycine were employed as complex agents in order to increase the permselectivity of metal ions. The experimental results show that the permselectivity coefficient, T(Cu)Ni, increases as the stoichiometric ratio of a complex agent to metal ions, PHI, and the pH value of complex solutions increase, but decreases as the current density increases. Based on the Nernst-Planck equation and interfaciaL quasi-equilibrium hypothesis, a theoretical approach is obtained from numerical calculation and found to be consistent with the experimentaL results as the current Density ranging from 0-1.5 mA/cm2 and PHI ranging from 0-0.5.