A comprehensive approach towards efficient removal of fluoride along with co-existing pollutants from real groundwater using electrocoagulation process

This study evaluated the effectiveness of electrocoagulation in treating fluoride-contaminated groundwater from Gharbar village, Jharkhand, where fluoride concentrations range from 3.76 to 12.9 mg L ^{− 1} along with other co-existing ions. The order of abundance of anions was sulfate > fluoride > nitrate > potassium > phosphate > chlorine, and for cations, it was magnesium > calcium. Optimal EC conditions were achieved for five groundwater samples (S1 to S5), with fluoride removal efficiencies from 89.58 to 96.40%, attaining the safe threshold of 1 mg L ^{− 1}. The process utilizes an electric potential of 12 V, an electrode gap of 0.5 cm, and a treatment time of 3600 s, using aluminium electrodes in bipolar mode. An additional adsorption step with activated charcoal (1 g 3 L ^{− 1} ) for 1800 s enhanced the treated water quality, reducing hardness, alkalinity, and turbidity, achieving fluoride removal rates between 93.45% and 99.82%. To replace laboratory-scale filter paper methods for floc separation, commercial ceramic candle-based filters and carbon gravity filters were employed. Analysis of the sludge via field emission scanning electron microscopy and energy dispersive X-ray analysis confirmed the capture of fluoride and other ions in metal hydroxide flocs. Kinetic analysis indicated that fluoride ion removal followed the first-order kinetic model. The optimized electrocoagulation process demonstrated an electric energy consumption of 3.2 kWh m ^{− 3}, electrode consumption of 0.2684 g L ^{− 1}, and theoretical H ₂ generation of 0.3581 L. The operating cost was estimated at 0.5030 US$ m ^{− 3} for electrocoagulation alone and 0.5185 US$ m ^{− 3} with adsorption and filtration, highlighting the feasibility and cost-effectiveness of this hybrid approach for fluoride removal from groundwater.