Fluoride Removal From Drinking Water by Electrocoagulation Using Iron and Aluminum Electrodes

Abstract

Background: Existence of fluoride in drinking water above the permissible level causes human skeletal fluorosis. Objectives: Electrocoagulation by iron and aluminum electrodes was proposed for removing fluoride from drinking water. Materials and Methods: Effects of different operating conditions such as treatment time, initial pH, applied voltage, type and number of electrodes, the spaces between aluminum and iron electrodes, and energy consumption during electrocoagulation were investigated in the batch reactor. Variable concentrations of fluoride solution were prepared by mixing proper amounts of sodium fluoride with deionized water. Results: Experimental results showed that aluminum electrode is more effective in fluoride removal than iron, as in 40 minutes and initial pH of 7.5 at 20 V, the fluoride removal process reached to 97.86%. The final recommendable limit of fluoride (1.5 mg/L) was obtained in 10 minutes at 20 V with the aluminum electrode. Conclusions: In electrocoagulation with iron and aluminum electrodes, increase of voltage, number of electrodes and reaction time as well as decrease of the spaces between electrodes, enhanced the fluoride removal efficiency from drinking water. In addition the effect of pH and initial concentration of fluoride varied with types of electrodes.