Synergistic Enhancement of Tetracycline Degradation via Photocatalytic Activation and Ammonium Persulfate Oxidation: Mechanistic Insights and Performance Evaluation

Abstract The integration of photocatalysis with persulfate‐based advanced oxidation processes demonstrates enhanced efficacy in antibiotic wastewater treatment. This study systematically investigated the synergistic degradation of tetracycline (TC) using a P‐doped g‐C 3 N 4 photocatalyst (PCN) coupled with ammonium persulfate (APS). Experimental results revealed that the PCN/APS composite system achieved between 18.8% and 66.6% higher degradation efficiency compared to individual photocatalysis and persulfate oxidation systems, respectively. Under optimized conditions (APS dosage = 1 mmol/L, reaction duration = 45 min, pH = 5), the system attained 99.8% TC removal efficiency. Notably, the photocatalyst maintained > 90% catalytic activity through three consecutive reuse cycles. Mechanistic analysis identified two predominant pathways: (1) van der Waals force‐mediated adsorption processes governing initial substrate enrichment, and (2) interfacial electron transfer from PCN's lamellar structure to APS, triggering substantial generation of sulfate (SO 4 • − ), hydroxyl (•OH), and superoxide (O 2 • − ) radicals. These reactive species collectively mediated oxidative degradation through noncovalent interactions.