Nickel Removal from Industrial Wastewater Using Electrocoagulation Process

Electrocoagulation (EC) process is an economical and environmental option for water and wastewater treatment systems. In the present study, a laboratory-scale electrocoagulation unit with a volume of 1.2 liters, equipped with iron and aluminum electrodes with dimensions of 1×50×120 mm, was used to remove nickel. Influence of the electrode type and distance, initial concentration, voltage, and pH on the nickel removal efficiency were studied in addition to reaction kinetics. Energy and electrode consumptions of these mentioned arrangements were obtained for different current intensities. The results demonstrated that the Ni removal efficiency changed from 93.7% to 98.1% by electrocoagulation using different arrangements of iron and aluminum electrodes at 20 V and 60 min. EC with an Fe(+)/Al(-) electrode pair after 60 min was able to achieve a 93.7% removal efficiency at 20 V, pH 7, and 250 mg/l initial concentration. The present study demonstrated that nickel removal increased with increasing voltage, pH and initial concentration. The increase in current intensity led to an increase in the energy consumption, which was obtained less for the pair of iron electrodes than other arrangements. Corresponding electrode consumptions of iron and aluminum anodes were determined as 0.87-1.31 and 0.28-0.45 kg/m3, respectively. In addition, the first-order model demonstrated an acceptable agreement with the experimental data.