Removal of low concentrations of nickel ions in electroplating wastewater by combination of electrodialysis and electrodeposition

Abstract

The low concentration of nickel in electroplating wastewater is difficult to treat to meet the discharge standard. In this study, a commercial cation exchange membrane was used to combine the electrodialysis on a titanium plate anode sintered ruthenium-iridium and the electrodeposition on a stainless steel cathode to reduce the nickel concentration to less 0.1 mg L−1. The electrolytic properties of the electrodialysis combined with the electrodeposition were investigated at different cell voltages, electrolysis time, initial electrolyte pH, electrolyte flow rates and initial Ni2+ concentrations. The results indicated that the Ni2+ concentration in the anolyte and the catholyte could be reduced to 0.015 and 0.085 mg L−1, respectively, with the initial Ni2+ concentration of 1.0 mg L−1, which could meet the most strict Ni2+ discharge standard of 0.1 mg L−1. The electrodeposition of Ni2+ on the cathode enhanced the migration of the Ni2+ in the electrolytes, which was beneficial to decrease the energy consumption. Therefore, the combination of electrodialysis and electrodeposition was promising to reduce the low concentration of Ni2+ in the electroplating wastewater.