Nickel removal from waste water by electrocoagulation with aluminum electrodes

In this study, the performance of electrocoagulation with aluminium electrodes for removing nickel from synthetic aqueous solutions and actual electroplating wastewater was investigated. Parameters affecting the electrocoagulation process, such as initial pH, current density, initial metal ion concentration and contact time were investigated. The removal efficiency is very high in the pH range 4-10. Increased current density accelerated the electrocoagulation process, however, on cost of increased energy consumption. Initial Ni 2+ concentrations of 100-300 mg/lit were quantitatively reduced under the admissible limits in only 10-20 minutes of electrolysis time respectively at the current density of 30 mA/cm 2 . The process has proved to be efficient in removing Ni 2+ ions also from industrial electroplating effluents, where an initial Ni 2+ concentration of 215 mg/lit fell under the legal limits in 20 minutes.