Nitrate removal from simulated wastewater by electrocoagulation: Impact of operating parameters on removal efficiency and energy consumption

Abstract

This study concerns the electrocoagulation (EG) process that is used to remove nitrate from simulated wastewater within an electrochemical cell containing a monopolar aluminium four-electrode. There are four effected parameters were chosen as a controllable variable; initial pH, applied potential, electrolysis time, and distance between electrodes, while there to responses were investigated under effect of these variables; nitrate removal efficiency and energy consumption (EC), so the new in this work is the using of four aluminium exchangeable electrodes and the investigation four operation parameters on nitrate removal and energy consumption efficiency as well as the optimization for the system. The range for the chosen studied variables is as follows: 7-11,2-10 volts,30-90 minutes, and 1-3 cm for initial pH, applied potential, electrolysis time, and distance between electrodes, respectively. The results show that nitrate removal efficiency ranged between 79.9 and 93.0 %, where the analysis variation (ANOVA) analysis shows that the electrolysis time is the most significance parameter was effect on the nitrate removal efficiency due to its highest F-value, and followed in effect by distance between electrode, applied potential, and initial pH according to their F-values 29.57, 14.38, and 3.86 for distance between electrodes, applied potential, and initial pH respectively. The energy consumption (EC) results ranged between 1.89- and 6.45 kW hr. m^-3. On the other hand, the maximum nitrate removal efficiency is 94.84 % at the optimum conditions at 11, 4.66 volts, 90 minutes, and 1 cm for initial pH, applied potential, electrolysis time, and distance between electrodes correspondingly, while the minimum value for the EC is 0.0508 kW hr. m^-3 at 7 initial pH solution, 4.26 volt applied potential, 30 minutes electrolysis time, and 1 cm distance between electrodes.