A triple-cathode electron-Fenton system for efficient Fe2+ regeneration and in-situ H2O2 electro-activation

Abstract

Electro-Fenton (EF) has shown great advantages in the effecient degradation of recalcitrant organic pollutants through in situ generation of •OH, and the main limitations on system performance are the efficiencies of H2O2 activation and Fe2+ regeneration. In this research, a triple-cathode EF system with a microbial fuel cell (MFC) cathode for the acceleration of Fe2+ regeneration, a gas diffusion electrode for H2O2 production and a stainless steel mesh (SSM) for electro-activation of H2O2 was designed for efficient degradation of organic pollutants. The triple-cathode EF exhibited improved removal rate for recalcitrant organic pollutants with an average electricity consumption of 18.2 kWh Kg−1 TOC for Rhodamine B degradation, and the dosage of Fe2+ could be reduced to 0.1 mM due to better utilization of H2O2 and inhibition of parasitic reactions. Electrochemical characterization and theoretical calculation revealed that both one-electron reduction and H*-mediated activation contributed to the electro-activation of H2O2 on SSM. This work demonstrates a novel construction and feasible approach for efficient EF with low cost.