Optimization of Nitrate Removal Efficiency and Energy Consumption Using a Batch Monopolar Electrocoagulation: Prediction by RSM Method

Abstract

The response surface method (RSM) was used to find out the best conditions for the nitrate removal by electrocoagulation (EC) process with aluminum electrodes. The independent variables were initial nitrate concentration, reaction time, initial pH, and cell voltage. A statistical analysis of variance (ANOVA) was performed for optimization of parameters obtained from the experimental data. A quadratic model was suggested as a good model for prediction of nitrate removal efficiency. The optimum conditions were obtained at pH 10, 17 V voltage, and 68 min when the initial nitrate concentration was found to be 226 mg/L. At the best conditions, the nitrate removal efficiency and energy consumption were obtained as 87.95% and 144.15 kWh/m3, respectively. In terms of nitrate removal efficiency and energy consumption, the coefficients of determinations were found to be 0.95 and 0.99, respectively. The results indicate that the initial nitrate concentration, reaction time, and cell voltage were found to be the most important parameters. The results also show good agreement between experimental data and the predicted equation.