Techno-economical evaluation of fluoride removal by electrocoagulation process: Optimization through response surface methodology Original Research Article

In this research, response surface methodology (RSM) was applied to evaluate the effect of main operational variables including initial pH, initial fluoride concentration, current density and reaction time for the removal of fluoride and its relative operating costs by electrocoagulation. It was found that the effect of initial pH was negligible on fluoride removal efficiency and operating costs. With the decrease of initial fluoride concentration, fluoride removal efficiency improved; however, it had no effect on operating costs. On the other hand, the increase of current density and reaction time severely influenced process performance and increase fluoride removal efficiency and operating costs. According to the ANOVA (analysis of variance) results, the models presented the high R2 values of 96.5% and 97.3% for fluoride removal efficiency and operating costs, respectively. The optimum initial pH, initial fluoride concentration, current density and reaction time were found to be 7, 25 mg/l, 0.0167 A/cm2, 25 min, respectively, for the removal of fluoride. Fluoride removal efficiency of 94.5% was observed in the experiment at optimum conditions which confirmed close to model predicted (90%) result.