Unraveling the\nDegradation Mechanism and Interaction\nMechanism of Ofloxacin Based on Reactive Oxygen Species via Electrochemically\nActivating Peroxymonosulfate

Abstract

Peroxymonosulfate (PMS) as an oxidant has been extensively\napplied\nto remove organic pollutants, but the molecular interaction mechanism\nof PMS and organic pollutants under the electrochemical process remains\nunclear. This work unraveled the interaction relationship of PMS on\nofloxacin (OFN) degradation by PMS-based electrochemical oxidation.\nThe results showed that hydroxyl and sulfate radicals generated from\nthe electrochemical reaction could effectively degrade OFN. Under\nthe electrochemical oxidation process, 100% or 12.1 ± 2.1% of\nOFN was degraded within 15 min in the presence or absence of PMS,\nrespectively. Quantum chemical calculations and molecular dynamics\nsimulations indicated that the hydrogen bonds and van der Waals force\nwere the primary interaction force between PMS and OFN. Besides, the\nPMS–OFN binding process was a stable dynamic process, and its\nstability was dependent on the number of hydrogen bonds generated.\nThe structure–activity relationship suggested that OFN was\ntransformed into short-chain intermediates with lower toxicity within\n15 min. Additionally, this electrochemical system for degrading OFN\nretained excellent reusability and recyclability, affording high oxidation\nability during successive cycles. More importantly, this electrochemical\nprocess could highly efficiently degrade various organic pollutants\n(4-chlorophenol, methyl orange, sulfamethoxazole, and perfluorooctanoic\nacid). This study provided a new possibility for the application of\nthe electrochemical system in large-scale wastewater treatment.