Comparative Effectiveness and Mechanism of Antibiotic Degradation by B/N-Doped Biochar-Supported Fe3S4 Activating Peroxydisulfate
Rice husk biochar (BC) was modified with boron (B) and nitrogen (N) doping and loaded with Fe3S4 to fabricate B-BC@Fe3S4 and N-BC@Fe3S4 catalysts for peroxydisulfate (PDS) activation and enrofloxacin (ENR) degradation. Characterization via SEM, BET, XRD, Raman, and XPS confirmed successful heteroatom incorporation and uniform Fe3S4 dispersion, enhancing specific surface area and defect sites. Degradation experiments showed that B-BC@Fe3S4 and N-BC@Fe3S4 achieved ENR removal efficiencies of 90.72% and 91.89%, respectively, significantly outperforming unmodified BC@Fe3S4 (82.21%). Mechanistic studies revealed that PDS activation proceeded via Fe3S4-mediated electron transfer generating radical species (SO4•−, •OH, O2•−) and via B/N functional groups promoting non-radical singlet oxygen (1O2) formation. Notably, N-BC@Fe3S4 exhibited superior resistance to Fe3+ leaching and greater environmental adaptability under varying pH, anion, and humic acid conditions. These findings demonstrate that B/N-doped biochar-supported Fe3S4 are effective catalysts for PDS activation, offering promising potential for antibiotic removal from real wastewater matrices.