The present work was carried out to assess the efficiency of iron (Fe) and aluminum (Al) electrodes in electrocoagulation (EC) process for removal of fluoride using aqueous solutions. Several operating parameters such as type of electrode, initial concentration of fluoride, current density, electrolysis time and NaCl amount were studied to achieve optimum conditions of high fluoride removal and energy consumption. Using Al electrodes, fluoride removal efficiencies of 80%, 83% and 87% were achieved while the Fe electrodes removed 51%, 54% and 56% using initial fluoride C0 =15, 10 and 5 mg/L, respectively. Besides, the increase of initial fluoride has caused a decrease of fluoride removal efficiency. By adding 0.5 g/L of NaCl to fluoride solutions, fluoride removal increased from 45 to 61.76% using Fe electrodes, while this efficiency passed from 56 to 66.47% using Al electrodes.
Energy consumption was voltage, intensity and time dependency. In optimum conditions (t = 60 min and DC= 27.8 mA/cm2), Al electrodes could remove up to 100% while Fe electrodes removed 77.4% during the whole of electrolysis. Therefore, Aluminum electrodes were more efficient in fluoride removal using EC but they require more energy during the EC process.