Remarkably enhanced sulfate radical-based photo-Fenton-like degradation of levofloxacin using the reduced mesoporous MnO@MnOx microspheres

Abstract

Sulfate radical-based advanced oxidation processes (SR-AOPs) are promising alternatives to conventional hydroxyl radical-AOPs for recalcitrant contaminants elimination in water treatment. Herein, the efficient and fast degradation of antibiotic levofloxacin (LEV) using mesoporous MnO@MnOx microspheres was successfully achieved with peroxymonosulfate (PMS) as an oxidant under simulated sunlight irradiation. Remarkably, MnO@MnOx catalyst achieves 98.1% degradation and 81.4% mineralization of LEV after being irradiated for 30 min, and SO4−, OH, O2− and 1O2 species play the imperative role in the SR-photo-Fenton-like oxidation process. Through the reaction intermediates identification, the LEV degradation pathways are speculated. The deterioration of performance is inconspicuous in the cyclic runs with negligible Mn-ions leaching. The excellent catalytic activity and stability of the H2-reduced MnO@MnOx microsphere are ascribed to the mesoporous structure, multivalence and oxygen vacancies, resulting in the large specific area, strong UV–vis response, effective charge separation coupling with desirable self-redox properties of Mn-ions on the catalyst surface. This study offers a useful guideline to efficiently degrade recalcitrant contaminants for water treatment.