Binder-Free Fe (II) Sustained-Release Electrode for Enhanced Flow-Through Electro-Fenton Degradation on Aniline-Containing Wastewater

The ferrous-based (Fe(II)) electro-Fenton (EF) process for pollutant removal in wastewater has attracted great attention, while the unstable Fe(II) ion continuous supply and low mass transfer efficiency are vital challenges to hinder the pollutant degradation effects and further practical applications. Herein, we proposed an Fe(II) sustained-release anode coupled with a flow-through system to address this bottleneck problem. In our study, a binder-free Fe(II) sustained-release electrode was synthesized by the electrospinning method and employed in an EF reactor to treat aniline-containing wastewater. The high catalytic iron species was well dispersed and nanoconfined in nanofibers, which ensures a continuous supply of Fe(II) ions and enables a controlled homogeneous/heterogeneous coexistence environment, benefiting aqueous aniline removal efficiency (96.1% of aniline removed within 120 min). The rough surface of nanofibers and flow-through configuration greatly accelerate mass transfer kinetics (k = 0.027 min–1, increased 6.5 times) since the contact chances between the targeted pollutants and the catalyst were mandatorily enhanced. The optimal conditions for aniline degradation were investigated. Four degradation pathways and probable mechanisms for aniline removal were proposed. CFD simulations were utilized to elucidate the fluid velocity distribution in the flow-through reactor. The work offers insights into constructing a rational EF system and developing a high-performance electrochemical technology for wastewater remediation.