Surface-catalyzed electro-Fenton with flexible nanocatalyst for removal of plasticizers from secondary wastewater effluent

Activation of H2O2 with metal-free catalysts is an efficient and environmentally benign alternative to electron-Fenton (EF) for organics degradation. In the present study, flexible nanocatalysts were synthesized with self-regulated metal oxide nanoparticles (FeOx NPs) for efficient removal of plasticizers from secondary wastewater effluent (SWE). Compared with NGr/EF and FeOx@Gr/EF systems, FeOx@NGr/EF could enhance the decay kinetics of plasticizers by 3.9–4.4 times and reduce 48–59% of the disposal cost. Reactive oxygen species tests and trapping experiments proved that the surface-catalyzed EF effectively broadened the range of solution pH. Density functional theory calculations coupled with electrochemical measurements indicated that the electron transfer rates between Fe-O-C atoms were enhanced with N-doping due to strong interactions between N-Fe bond. The synergistic effects of FeOx and N could improve the oxygen reduction activity for H2O2 generation, and accelerate electron transfer between FeOx/NGr and H2O2 for •OH generation, offering an alternative for wastewater treatment. [Display omitted] •Nano-catalyst (FeOx@NGr) is synthesized by self-regulated solvothermal method.•Decay kinetics of plasticizers on FeOx@NGr (pH 7) are 3.9–4.4 times that in EF (pH 3).•FeOx@NGr/EF reduces the cost of organics removal by 48–59% in secondary wastewater effluent.•Synergistic effects of Fe(II) and N improve H2O2 decomposition for •OH generation.•Surface-catalyzed EF has the potential for treating wastewater with a wide range of pH.