Amorphous MnO2 Supported on CN@SiO2 for Levofloxacin Degradation via a Non-Radical Pathway by PMS Activation

Mn-based catalysts have been extensively studied in advanced oxidation processes based on peroxymonosulfate (PMS) oxidants, demonstrating their significant potential for treating antibiotic-contaminated wastewater. In this study, an amorphous MnO2-based composite catalyst (MnO2/CN@SiO2) was prepared and used to activate PMS for degrading levofloxacin (LEV). The effects of reaction conditions, such as reaction temperature, catalyst dosage, PMS concentration, and solution pH, on LEV degradation were comprehensively investigated. The interference of water components, e.g., NO3−, SO42−, Cl−, CO32−, and humic acid, on the degradation efficiency of LEV was analyzed, and the stability of the catalysts was explored by cycling experiments. Finally, radical quenching experiments and electron paramagnetic resonance spectroscopy were employed to elucidate the contribution of active species to the degradation reaction process. A non-radical-based pathway for LEV degradation was proposed based on these results.