Influence of the co-ions on the transport of sulfate through anion exchange membranes

Abstract

[EN] The increasing demand for clean industrial processes has intensified the use of electrodialysis (ED) in the treatment of metal containing effluents from plating processes. Nickel rinsewater is a multicomponent solution that can be treated by ED in order to recover chemicals and reuse water. The investigation of the different phenomena involved in the transport of anions through anion-exchange membranes in this wastewater has been performed in different synthetic solutions by chronopotentiometry. Parameters like the limiting current density (i(lim)), the plateau length (Delta U-m), the resistance of the ohmic region (R-ohm) and the resistance of the overlimiting region (R-3) were also determined. Even though an anion exchange membrane (AEM), the limiting current density was affected by the proton leakage phenomena, indicated that the proton H+ has a greater effect than the other co-ions (Ni2+, Mg2+ and Na+). Ohmic resistances were reduced and plateau lengths were increased in the presence of protons. For salts solutions (without acid) the highest diffusion coefficients and lowest co-ion hydrated radii gave the highest plateau lengths and i(lim), but the lowest R-ohm.