Development of a three-dimensional electro-Fenton system packed with C-PTFE/Fe–Co–C hybrid particle electrodes for simultaneous H2O2 generation and activation into •OH

Abstract

Three-dimensionally heterogeneous electro-Fenton (3DEF) system is an energy-efficient technology for wastewater treatment, the performance of which was fundamentally dependent on the activity of filled particle electrodes toward the production of active species. In this study, the carbon black-polytetrafluoroethylene (C-PTFE) composite particles and iron-cobalt-carbon black (Fe–Co–C) composite particles were separately fabricated by one-step pyrolysis and both used as the particle electrodes in the 3DEF system for carbamazepine (CBZ) degradation. The C-PTFE particles with high hydrophobicity as cathode catalyst exhibited high H2O2 electro-generation performance. Meanwhile, the Fe3+/Fe2+ and Co3+/Co2+ redox cycles were promoted mutually in Fe–Co–C particles, which was beneficial for •OH formation and CBZ degradation. Under the optimized condition (e.g., pH = 3, current density = 10 mA cm−2), approximately 100 % of CBZ and over 80 % of COD were achieved at within 60 min. Noticeably, the synergistic performance of C-PTFE and Fe–Co–C particles in the 3DEF system exhibited little dependence on solution pH in the range of 3–9. The calculated energy consumption was as low as 0.0077 kW h g−1 COD, which was much less than those reported in many previous literatures. Chlorella growth inhibition experiments demonstrated that the toxicity of CBZ was alleviated due to the catalytic degradation of 3DEF system. Generally, the 3DEF system packed with hybrid C-PTFE and Fe–Co–C particle electrodes may be a promising technology for the wastewater treatment.