Fe3O4@Fe2O3 carbon aerogel particle electrodes for three-dimensional electro-Fenton oxidation: A novel mechanism promoted by non-radical pathway

Abstract

Three-dimensional electro-Fenton (3D-EF) has exhibited strengths over traditional electro-Fenton (EF) process for water decontamination, but recent researches on 3D-EF are focused on the decontamination mechanism driven by the radical pathway which was environmentally sensitive and poor in anti-interference capability. This study explored the non-radical mechanism in the 3D-EF process by preparing a novel Fe₃O₄@Fe₂O₃/carbon aerogel-700 (FFCA-700) particle electrode (PE) to construct a 3D-EF system promoted by non-radical pathway. The electrodes induced electric field spontaneously polarized FFCA-700 into PEs which led to higher active surface areas of electrodes and the enhancement of mass transfer. Numerous polarized FFCA-700 served as electron donor for dissolved O₂ to obtain electron to form ·O₂^– while the increase in positive charge of the graphitized carbon, caused by the functional group containing electron-rich oxygen, was conducive for ·O₂^– to transform to ¹O₂ thus promoting the non-radical pathway. Tetracycline (TC) was selected as the model pollutant to evaluate and compare the remediation performance of different systems. The results suggested that FFCA-700-3D-EF system performed well for pollutant removal in real wastewater. Overall, this study provided a reference for the design and optimization of CPEs and the guidance for the mechanism studies on remediation of organically contaminated wastewater by 3D-EF process.