The efficiency of the electrocoagulation process in reducing fluoride: application of inductive alternating current and polarity inverter

In this study, using hybrid Al and Fe plate electrodes in an electrochemical cell by using inductive alternating current and polarity inverter as an alternative method for decreasing fluoride in drinking water sequentially, by the electrocoagulation process has been evaluated. The effect of operational parameters such as the type of current, paired hybrid electrodes and polarity inverter, pH, current density, electrolysis time, charge loading and flow rate on the percent of fluoride removal along with the amount of energy and electrode consumed and amount of sludge produced was evaluated. In the following optimum operation conditions: paired hybrid Al–Fe electrodes with polarity inverter, pH = 6, current density = 12 mA/cm², electrolysis time = 40 min, charge loading 0.609 Faradays/m³ and flow rate 75 ml/min, the efficiency of fluoride removal, energy and electrode consumption, flow efficiency, amount of sludge produced and sedimentation capacity were, respectively, 95% (from initial 4.93 to 0.24 mg/l), 0.9 kWh/m³, 1.42 kg/m³, 110%, 0.108 kg/m³ and 0.073 l/g. The results showed that the electrocoagulation process by using alternating current and polarity inverter is a very efficient method for removing fluoride from drinking water.