Design of a neutral electro-Fenton system with Fe@Fe2O3/ACF composite cathode for wastewater treatment

The narrow pH range limits the wide application of Fenton reaction in the wastewater treatment. It is of great importance to widen working pH range of Fenton reaction from strong acidic condition to neutral, even basic ones. In this study, for the first time nanostructured Fe@Fe2O3 was loaded on active carbon fiber (ACF) as an oxygen diffusion cathode to be used in a heterogeneous electro-Fenton (E-Fenton) oxidation system. This novel Fe@Fe2O3/ACF composite cathode was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), and element mapping. On the degradation of dye pollutant rhodamine B in water, this heterogeneous E-Fenton system with the Fe@Fe2O3/ACF cathode showed much higher activity than other E-Fenton systems with commercial zero valent iron powders (Fe0) and ferrous ions (Fe2+) under neutral pH. On the basis of experimental results, we proposed a possible pathway of rhodamine B degradation in this heterogeneous Fe@Fe2O3/ACF E-Fenton process. This heterogeneous E-Fenton system is very promising to remove organic pollutants in water at neutral pH.