Electrochemical process for 2,4-D herbicide removal from aqueous solutions using stainless steel 316 and graphite Anodes: optimization using response surface methodology

In this experimental study, an electrochemical cell (100 cc) equipped with anode electrodes of SS316 and graphite and the cathode electrode of SS316 in parallel form at a distance of 1 cm from each other was used to degradation the 2,4-Diclorophenoxy acetic acid (2,4-D) herbicide. The results showed that the removal efficiency of 2,4-D herbicide in initial concentrations of 50 and 100 mg/L under optimum conditions (pH = 7, electrolysis time = 50 min and current density = 3 mA/cm2) using the graphite anode electrode was 73.5% and 47.76%, respectively; however, using the SS316 electrode, the removal efficiency was 44.23% and 17.65%, respectively. The highest removal of 2,4-D in electrochemical process was 95.87% for herbicide initial concentration of 50 mg/L by graphite anode electrode. Considering the efficiency of 2,4-D removal, the determined coefficients were found to be 0.91–0.93. The amount of energy consumed for SS316 and graphite electrodes was obtained to be 6.308 and 5.99 kWh/m3, respectively. Results revealed that the electrochemical process with graphite anode electrode has an acceptable efficiency in removing the 2,4-D herbicide and can be used as an appropriate pretreatment in treating the wastewater containing the resistant compounds such as phenoxy group herbicides (2,4-D).