Binder-Free\nFe (II) Sustained-Release Electrode for\nEnhanced Flow-Through Electro-Fenton Degradation on Aniline-Containing\nWastewater

The ferrous-based (Fe(II)) electro-Fenton (EF) process\nfor pollutant\nremoval in wastewater has attracted great attention, while the unstable\nFe(II) ion continuous supply and low mass transfer efficiency are\nvital challenges to hinder the pollutant degradation effects and further\npractical applications. Herein, we proposed an Fe(II) sustained-release\nanode coupled with a flow-through system to address this bottleneck\nproblem. In our study, a binder-free Fe(II) sustained-release electrode\nwas synthesized by the electrospinning method and employed in an EF\nreactor to treat aniline-containing wastewater. The high catalytic\niron species was well dispersed and nanoconfined in nanofibers, which\nensures a continuous supply of Fe(II) ions and enables a controlled\nhomogeneous/heterogeneous coexistence environment, benefiting aqueous\naniline removal efficiency (96.1% of aniline removed within 120 min).\nThe rough surface of nanofibers and flow-through configuration greatly\naccelerate mass transfer kinetics (<i>k</i> = 0.027 min<sup>–1</sup>, increased 6.5 times) since the contact chances between\nthe targeted pollutants and the catalyst were mandatorily enhanced.\nThe optimal conditions for aniline degradation were investigated.\nFour degradation pathways and probable mechanisms for aniline removal\nwere proposed. CFD simulations were utilized to elucidate the fluid\nvelocity distribution in the flow-through reactor. The work offers\ninsights into constructing a rational EF system and developing a high-performance\nelectrochemical technology for wastewater remediation.