Application of electro-Fenton process for treatment of water contaminated with benzene, toluene, and p-xylene (BTX) using affordable electrodes

Electro-Fenton (EF) process was utilized for degradation of benzene (B), toluene (T), and p-xylene (X) (BTX) in aqueous solutions using different electrodes. The cathode was made from carbon felt, while different materials were used as anodes including carbon, stainless steel, and nickel. Complete degradation of BTX was attained within 30 min under favored conditions. However, TOC removal of BTX in the mixture was only 75% at early stages of the EF process due to the remaining organic by-products. The effects of operational conditions at different initial concentrations of BTX were assessed in-depth. The EF process was able to attain 95.4%, 88.7%, and 87.6% TOC removal efficiencies at an initial concentration of 150 mg/L using sacrificial stainless steel, carbon, and nickel anodes respectively in 60 min. The stainless steel anode in the mode of the sacrificial electrode was favored due to the continuous production of Fe2+ in the solution. The precipitated sludge during the EF process was treated and used to improve the degradation of BTX. A cost estimation study showed that treatment of one cubic meter of BTX contaminated water by electro-Fenton process costs $1.40 under certain conditions.