Elimination of chloramphenicol through electro-fenton-like reaction: Reaction mechanism and electron transfer pathway

Abstract

An electro-Fenton-like reaction process relying on peroxymonosulfate activation can stably degrade chloramphenicol (CAP) within 16 min, where the kinetic rate constant can be as high as 0.089 min⁻¹ and the energy consumption value can be as low as 25.1 kWh•m^⁻³. Evidence indicated that the use of a Na₂SO₄ solution as the electrolyte can enhance CAP degradation due to rapid electron transfer properties. The generated electrons and active free radicals are responsible for CAP degradation, and the electrons can be transferred from the highest occupied molecular orbital of CAP to the lowest unoccupied molecular orbital of peroxymonosulfate via the PbO₂ electrode. Density functional theory calculations based on Fukui index analysis elucidated the key attack sites in CAP; moreover, reaction-free energy calculations shed light on potential CAP degradation pathways. Not only does this study afford an insight into the activation of peroxymonosulfate for organic pollutant degradation but also provides an innovative technology with potential applications in wastewater purification.