Analysis of Tetracycline Modification Based on g-C3N4 Photocatalytic Degradation

To address challenges in antibiotic wastewater treatment, we synthesized a series of graphitic carbon nitride (g-C3N4)-based photocatalysts (BCN, PCN, TCN, BTCN, and TCNE-modified PTCN) via defect engineering. TCNE modification disrupted the triazine ring-bridging amino network in PTCN, forming a porous structure with enhanced specific surface area validated by SEM/TEM while retaining the graphene-like framework confirmed by XRD/FTIR. Photoluminescence (PL) analysis revealed prolonged photogenerated carrier lifetime and improved separation efficiency in PTCN, achieving 89.10% degradation of chlortetracycline hydrochloride under visible light—1.65-fold higher than pristine g-C3N4. Mechanistic studies identified superoxide radicals (•O2−) as dominant active species, generated via O2 activation at defect sites and efficient electron-hole utilization. Optimized conditions enabled PTCN to maintain high activity across a broad pH range and retain 82.59% efficiency after five cycles. This work advances defect-engineered photocatalyst design for adaptable, high-performance antibiotic degradation, offering practical insights for wastewater remediation.