Comparing the Electrocoagulation and Electro-Fenton Processes for Removing Nitrate in Aqueous Solution for Fe Electrodes

Background and Nitrate contamination in aqueous solution has become an increasingly serious environmental problem. Hence, in this study removal of nitrate in aqueous solution was reviewed using electrocoagulation (EC) and electro-fenton (EF) processes for Fe electrodes. In the present study, an EC and EF reactor in a lab scale to an approximate volume of 1 liter was proposed for removing of nitrate polluted water which was equipped with four Fe-Fe electrodes with dimensions 200 × 20 × 2 mm. The effects of operating parameters such as initial nitrate concentration, applied voltage (10-30 V), initial pH of the solution (3-12), different initial hydrogen peroxide (for EF process) and reaction times (5-30 minutes) were evaluated. The batch experimental results showed that initial nitrate concentration, initial pH of the solution, different applied voltages, initial H2O2 concentration and reaction times were highly effective on the nitrate removal efficiency in these processes. Based on the results, over 88% of nitrate in optimum condition (pH = 8, applied voltage = 30 V, initial nitrate concentration of 100 mg/l) have been removed in EC process. In addition, the application of EF process can remove 93% of nitrate at pH = 3, applied voltage = 30 V, initial nitrate concentration of 100 mg/l and 5 ml H2O2/l. Both EC and EF technologies can highly remove nitrate in aqueous solution. However, it was found that much better nitrate removal efficiency could be achieved by EF process than by EC process at the same condition.