Optimizing Fluoride Removal and Energy Consumption in a Batch Reactor Using Electrocoagulation: A Smart Treatment Technology

Abstract

Electrochemical-based approaches have gained much attention as sustainable, eco-friendly and cleaner methods of treatment technologies as they are less sludge producing. The presence of excess fluoride in drinking water supplies is responsible for dental, skeleton and other forms of fluorosis. Among various defluoridation techniques available, electrocoagulation (EC) process was experimentally applied and optimized aiming higher removal efficiency along with minimum energy consumption. Electrocoagulation process was employed at batch scale using both aluminium and iron electrodes, and a comparative assessment was carried out. The effects of initial pH (4–10), applied current (0.2–1.0 A), initial F− concentration (5–20 ppm) and reaction time (5–30 min) were explored. The EC reactor was optimized for initial F− concentration of 20 ppm, applied current of 0.5 A, pH 6 and reaction time of 20 min using aluminium electrodes giving 97.6% removal efficiency and energy consumption of 0.0195 W hour per gm of fluoride. Operational cost was also analysed, and it was found that among the two, aluminium electrodes outclassed iron electrodes in terms of higher removal efficiency proving cost effective as well.