Cost-effective electro-Fenton using modified graphite felt that dramatically enhanced on H2O2 electro-generation without external aeration

•A simple method using carbon black and PTFE was firstly developed to modify graphite felt.•The production of H2O2 increased 10.7 times at carbon black to PTFE mass ratio of 1:5.•After modification the cathode showed a more stable performance over a wider pH and O2 flow rate.•It accomplished a cost-effective H2O2 production without external aeration.•The complete removal of methyl orange by electro-Fenton with modified cathode was more efficient.

A simple method using carbon black and polytetrafluoroethylene (PTFE) was firstly developed to modify graphite felt which was widely employed as cathode for electro-Fenton, improving the in situ production of H2O2 by about 10.7 times at the optimum carbon black to PTFE mass ratio of 1:5. It was observed that after cathode modification the effect of operating parameters on H2O2 electro-generation, such as O2 flow rate, current density and initial pH, were absolutely different with that before modification, demonstrating a more stable performance over a wider pH and oxygen flow rate ranges. The maximum accumulation of H2O2, up to 472.9 mg/L, was obtained at 50 A/m2 without aeration at initial pH 7, and the H2O2 production capacity remained over 90% after 10-times reuses. The complete removal of 50 mg/L methyl orange by electro-Fenton on the modified cathode was achieved within 15 min, while the total organic carbon removal efficiency reached 95.7% at 2 h, which was more than four-times that on the unmodified one (23.3%). Such a cathode modification accomplishes an efficient and greatly enhanced H2O2 production without external aeration, offering a cost-effective degradation of organic pollutants by electro-Fenton.