Unveiling the Reactive Species and Synergistic Mechanism in Nitrogen-Doped Sea Buckthorn Carbon-Catalyzed Ozonation for Antibiotic Removal

Antibiotic residues in aquatic environments exhibit high environmental persistence and pose potential ecological risks, highlighting the need for efficient and low-cost advanced treatment technologies. In this study, nitrogen-doped sea buckthorn wood-derived carbon catalysts (NSBC-x) were prepared from sea buckthorn wood waste through a ball-milling–nitrogen-doping–pyrolysis strategy and applied to catalytic ozonation for tetracycline (TTCH) degradation. The pyrolysis temperature significantly affected the catalytic performance of the materials, with NSBC-800 exhibiting the highest activity. Under an initial TTCH concentration of 50 ppm, a catalyst dosage of 0.10 g L−1, and an ozone flow rate of 0.10 L min−1, NSBC-800 achieved a TTCH removal efficiency of 94.72%. Reactive-species quenching experiments indicated that superoxide radicals (O2·−) and singlet oxygen (1O2) were the predominant reactive species in the system. The superior catalytic performance of NSBC-800 may be attributed to the synergistic effects of nitrogen-containing active sites, structural defects, accessible pore channels, and a moderately graphitized carbon framework, which collectively facilitate ozone adsorption, interfacial electron transfer, and reactive oxygen species (ROS) generation.