The Characteristics of Degradation of Enrofloxacin by Vis / BC-BiOI / PMS Photocatalytic System Based on BiOI-Modified Biochar

The overall goal of this research was to develop the Vis/BC-BiOI/PMS system, integrating multiple advanced oxidation technologies, to effectively treat Enrofloxacin (ENR), a typical antibiotic pollutant known for its resistance to degradation. The modified biochar underwent thorough characterization, including analysis of its structure, morphology, surface material composition, and other properties. Adsorption experiments revealed that the Biochar (BC) component exhibited the most robust adsorption removal rate, reaching 15%, followed by Bismuth Iodide Oxide loaded Biochar (BC-BiOI) (9%) and Bismuth Iodide Oxide (BiOI) (2%). The control experiment was separately conducted under dark or visible light conditions, demonstrating that photocatalysis primarily contributed to ENR degradation. The subsequent degradation kinetics also showed this point. The pathway and mechanism of ENR degradation in the Vis/BC-BiOI/PMS system were extensively analyzed. The contribution of each active substance was determined through free radical quenching tests and Electron Paramagnetic Resonance (EPR) spectra. The results indicated that ·OH and SO 4 − · played dominant roles in the early stages of ENR degradation, while 1 O 2 became the primary contributor in the later stages, with 1 O 2  > ·OH > SO 4 − ·. In addition, the toxicity and applicability of the Vis/BC-BiOI/PMS system were evaluated. This study demonstrates the effectiveness and feasibility of the Vis/BC-BiOI/PMS system in treating ENR wastewater.