Efficient Gatifloxacin Degradation by Underwater Bubble Discharge Enhanced With Nitrogen‑Rich g‑C3N5: Process Optimization and Mechanistic Insights

ABSTRACT Low‐temperature plasma synergistic photocatalysis is an effective technology for antibiotics degradation in water. To enhance the catalytic performance in the plasma‐catalytic process and address the high electron‐hole recombination of g‐C 3 N 4 , nitrogen‐rich catalyst g‐C 3 N 5 was synthesized and integrated into an underwater bubble discharge plasma (UBDP) for gatifloxacin degradation. The results showed that the UBDP/g‐C 3 N 5 system achieved a degradation rate of approximately 90% within 15 min. In actual wastewater, HCO 3 − and SO 4 − anions, along with some organic species significantly reduced the degradation efficiency. ·OH and h + are the primary contributors to the degradation process within the UBDP/g‐C 3 N 5 . Based on intermediate analysis, three potential degradation pathways were proposed, and toxicity evaluation confirmed effective reduction of ecological risk following treatment.