Nickel (II) removal from real electroplating wastewater in an electrocoagulation reactor: parametric optimization by response surface methodology

Electrocoagulation (EC) process was successfully applied and optimized for the removal of nickel (Ni) from real electroplating wastewater to achieve higher removal efficiency with low energy consumption. In the present study, an electrocoagulation reactor employing iron electrodes was set up for the experimental work. Response surface methodology (RSM) for a four-factorial central composite design (CCD) was applied to study the effects of process parameters on removal efficiency and energy consumption. Maximum Ni(II) removal efficiency of 95.16% was attained on optimization at an applied current of 0.31 A, an initial nickel concentration of 10 ppm, an application time of 18 min, and a pH of 7 along with the energy consumption of 0.443 Wh/g. With the help of the obtained three-dimensional (3D) plots, the interaction between the process variables was evaluated. By analysing the variance (ANOVA), the generated models were successfully validated.