Electrochemical treatment of sunflower oil refinery wastewater and optimization of the parameters using response surface methodology

Abstract

Combined electrocoagulation (EC) + electrooxidation (EO) process was compared with electrochemical peroxidation (ECP) treatment process to treat sunflower oil refinery wastewater. The effect of applied current density, pH/H2O2 dosage, and operation time in the removal of chemical oxygen demand (COD), soluble COD, total organic carbon, and dissolved organic carbon (DOC) were studied using Box Behnken Design. In EC process, decrease in organic concentration was observed as the time and current density increased. The optimized conditions for EC process were achieved at pH 6.07 when a current density of 5.69 mA cm−2 was applied for 18 min. The EO removed about 90% of DOC at an optimized pH of 5.27 and current density of 11.56 mA cm−2 when operated for 400 min. The combined EC + EO process was successful compare to ECP process in removing between 90 and 95% of organic pollutant from the sunflower oil refinery wastewater. The energy consumption was calculated to compare between the process efficiency of EC + EO and ECP and found that EC + EO was more efficient process. The reaction rate followed a first order kinetics validated with a high R2 value (0.96).