The widespread contamination of aquatic systems by ciprofloxacin (CIP)—a persistent fluoroquinolone antibiotic—poses severe ecological risks due to its antibacterial resistance induction. Conventional sulfate radical-based advanced oxidation processes (SR-AOPs) suffer from inefficient catalyst synthesis, exemplified by low-yield ZIF-67 precursors (typically <25%). To address this, a nitrogen-doped carbon composite Co₃O₄/N@C was synthesized via ammonia-assisted ligand exchange followed by pyrolysis, using N-doped ZIF-67 as a self-sacrificial template. The ammonia incorporation quadrupled precursor yield compared to ammonia-free methods. This catalyst activated peroxydisulfate (PDS) to degrade 95% CIP within 90 min under the optimized conditions (0.5 g/L catalyst, 2 mmol/L PDS, pH 5), representing a 30% enhancement over non-ammonia analogs. Mechanistic studies identified singlet oxygen (¹O₂) as the dominant reactive species, facilitated by N-doped carbon-mediated electron transfer. This strategy overcomes the scalability barrier of MOF-derived catalysts for practical antibiotic wastewater remediation.

The efficient removal of antibiotic contaminants from aquatic systems remains a significant challenge due to their persistence and complex environmental matrices. In this study, a CuO-loaded biochar (CuO–BC) composite was developed as an efficient catalyst for peroxydisulfate (PDS) activation toward ciprofloxacin (CIP) degradation. The CuO–BC exhibited superior catalytic performance, achieving rapid CIP removal over a wide pH range with strong resistance to coexisting ions. Mechanistic investigations revealed that both radical (SO₄•⁻ and •OH) and non-radical pathways (¹O₂ and electron transfer) contributed to CIP degradation. Quenching experiments, electron paramagnetic resonance (EPR), and probe analyses confirmed the coexistence of multiple reactive oxygen species (ROS), with interfacial electron transfer between Cu species and biochar appearing to play a significant role. The synergistic coupling of Cu²⁺/Cu⁺ redox cycling and the conductive biochar matrix facilitated efficient electron transport and selective ROS generation. Furthermore, the system was successfully applied in a simulated permeable reactive barrier (PRB), exhibiting stable degradation performance under continuous-flow conditions. This study provides new insights into interfacial PDS activation mechanisms and offers a promising strategy for designing efficient catalytic systems for antibiotic removal in complex water environments.

The efficient removal of antibiotic contaminants from aquatic systems remains a significant challenge due to their persistence and complex environmental matrices. In this study, a CuO-loaded biochar (CuO–BC) composite was developed as an efficient catalyst for peroxydisulfate (PDS) activation toward ciprofloxacin (CIP) degradation. The CuO–BC exhibited superior catalytic performance, achieving rapid CIP removal over a wide pH range with strong resistance to coexisting ions. Mechanistic investigations revealed that both radical (SO₄•⁻ and •OH) and non-radical pathways (1O2 and electron transfer) contributed to CIP degradation. Quenching experiments, electron paramagnetic resonance (EPR), and probe analyses confirmed the coexistence of multiple reactive oxygen species (ROS), with interfacial electron transfer between Cu species and biochar playing a dominant role. The synergistic coupling of Cu2+/Cu+ redox cycling and the conductive biochar matrix facilitated efficient electron transport and selective ROS generation. Furthermore, the system was successfully applied in a simulated permeable reactive barrier (PRB), exhibiting stable degradation performance under continuous-flow conditions. This study provides new insights into interfacial PDS activation mechanisms and offers a promising strategy for designing efficient catalytic systems for antibiotic removal in complex water environments.