One-step calcination synthesis of rice husk biochar-doped g-C3N4 for efficient photodegradation of norfloxacin

Norfloxacin (NOR), a quinolone antibiotic contaminant, poses significant environmental and health risks. In this study, rice biochar-doped g-C₃N₄ (BCN) photocatalyst was fabricated via a one-step calcination approach. Substitution of bridged nitrogen with carbon atoms created delocalized π bonds, which acted as both physical bridges between atrazine ring and electronic conduits to facilitate charge transfer. Among the prepared catalysts, the BCN 5 composite demonstrated the greatest performance of NOR photocatalytic degradation, presenting a NOR removal efficiency of 88.11% with a rate constant of 2.94 × 10 - ² min - ¹ over 2 hours under visible light, approximately 1.51 times that of pure graphitic carbon nitride (58.46%). It showed a promising reusability and stable properties, maintaining 85.13% of its original performance after five cycles. Mechanistic analysis identified superoxide radicals as a dominant substance affecting the degradation of NOR. This research highlights the potential of one-step synthesized rice husk biochar/g-C₃N₄ composites as an efficient, low-cost photo-catalyst applied in environmental remediation and water treatment.