Enhanced Degradation of Marbofloxacin via a Synergistic Photoelectro-Fenton-Peroxymonosulfate Process: Kinetic and...

Marbofloxacin (MAR), an ecologically hazardous and persistent fluoroquinolone (FQ) antibiotic, represents a serious environmental concern, necessitating the development of highly effective treatment technologies. This study applied a hybrid Photoelectro-Fenton (PEF) process coupled with peroxymonosulfate (PMS) activation to generate both hydroxyl and sulfate radicals for MAR degradation. Under optimized conditions (300 mA, 0.5 mM PMS, 35 W m^-2 UV, 0.2 mM Fe²⁺, pH 3.0), near-complete degradation (99.98 %) and mineralization (97.8 % Total Organic Carbon (TOC) removal) of MAR were achieved within 240 min. The degradation kinetics followed a pseudo-first-order approach with a rate constant of k₁ = 0.0385 min^-1 (R² = 0.996), and the degradation half-life was estimated to be 18 min. The response surface analysis verified that the dominant variables in the degradation process were the concentration of PMS and the applied current. The process required a specific energy consumption (SEC) of 72 kWh·m^-3 under these conditions. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis identified transformation products resulting from the cleavage of the piperazine ring and subsequent hydroxylation reactions. The PEF-PMS process exhibited high efficiency, attributable to the synergistic action of multiple reactive radical species, and thus provides a promising route for the near-complete mineralization of recalcitrant FQ antibiotics and a scientific basis for assessing its applicability and further optimization in more complex water matrices.