Removal of co-existing Fe(II), As(V) and fluoride ions from groundwater by electrocoagulation

This work report results of experimental studies on concurrent removal of co-existing Fe(II), As(V) and fluoride ions from groundwater by electrocoagulation (EC). Experimental studies were completed to explore the impact of initial pH, current density, initial ion concentration, stirring speed, salt dose, and electrode spacing on removing co-existing As(V), Fe(II), and fluoride ions. Experimental results infer that contaminated groundwater containing 400 μg/L of As(V), 20 mg/L of Fe(II) and 10 mg/L fluoride ions may be treated by EC using a current density of 0.432 mA/cm², salt dosage of 0.30 g/L, initial pH of 7 and stirring speed of 200 RPM within 60 min. Various other water quality parameters like residual TDS, sulfate ions, nitrate ions, chloride, phosphate ions, hardness, turbidity and alkalinity during the EC process were found to vary at different operating conditions. Experimental analysis shows that the presence of co-existing Fe(II), As(V) and fluoride ions in the water improve the removal efficiency of pollutant ions. Kinetic analysis showed that the removal of arsenic, iron, and fluoride ions followed the apparent first-order model. EDAX investigation of the sludge endorses the entrapment of fluoride, Fe, As along with other ions like Ca, Na, Cl, Al etc., by the metal hydroxide flocs.