A dual-cathode electro-Fenton oxidation coupled with anodic oxidation system used for 4-nitrophenol degradation

► Gas diffusion electrode and graphite electrode were used as the dual-cathode. ► The dual-cathode oxidation can reduce the amount of Fe2+ for organics degradation. ► Both electro-Fenton and anodic oxidation are involved in the dual-cathode process. ► The simultaneous removal of carbon and nitrogen with a high MCE was achieved. ► Nitrogen conversion via denitration, NO2− oxidation and NO3− reduction.