A dual-cell wastewater treatment system with combining anodic visible light driven photoelectro-catalytic oxidation and cathodic electro-Fenton oxidation

In this study a dual-cell wastewater treatment system was constructed by coupling anodic photo-electrochemical/electro-Fenton (PEC) cell and cathodic electro-Fenton (EF) cell (D-PEC-EF), with the Bi2WO6 nanoplates deposited on fluorine-tin oxide glass as the anode (Bi2WO6/FTO) and Fe@Fe2O3 core-shell nanowires supported on activated carbon fiber (Fe@Fe2O3/ACF) as the gas diffusion cathode. The two separated cells could degrade rhodamine B (RhB) simultaneously and thus enhance the degradation efficiency and the TOC removal significantly in comparison with that of counterpart single-cell PEC-EF system (S-PEC-EF) because of more hydrogen peroxide electro-generated on the Fe@Fe2O3/ACF cathode by photo-generated electrons transferred from the Bi2WO6/FTO anode and less hydrogen peroxide consumed by anodic oxidation owing to the partition of two cells, which enhanced both PEC and EF oxidation ability and improved both photocatalytic quantum efficiency and overall current efficiency significantly. This study could not only provide a high effective and energy-saving advanced oxidation technology for wastewater treatment, but also deepen understanding of the synergic effect in dual-cell electrochemical process.