Fe-Cu bimetallic microinterface-regulated advanced oxidation process for synergistic degradation of binary...

The competitive degradation mechanisms of multiple antibiotics in complex aquatic environments remain poorly understood. A binary composite pollution system was constructed using sulfamethoxazole (SDZ) and ciprofloxacin (CIP) as model contaminants. With an iron‑copper bimetallic co-doped biochar catalyst (nZVI/Cu@N-BC), complete degradation of both antibiotics was achieved within 60 min. Compared to monometallic counterparts under identical loading and reaction conditions, the nZVI/Cu@N-BC increased the degradation rates of CIP and SDZ by at least 60 % and 20 %, respectively. The nZVI/Cu@N-BC also exhibited strong anti-interference capability, along with excellent adaptability to coexisting ions, various real water matrices, and a wide pH range. Mechanistic investigations revealed that the iron/copper multivalent cycling and synergistic effects between CO and pyridine nitrogen functional groups collectively facilitate pollutant degradation. Density functional theory (DFT) simulations and degradation pathway analysis further demonstrated that molecular structural differences and intermolecular interactions modulate the singlet oxygen (¹O₂) attack behavior. This system effectively purifies antibiotic-contaminated water and provides a feasible strategy for the synergistic treatment of multiple emerging pollutants.