Norfloxacin Degradation by Persulfate Activated with Cu₂O@WO₃ Composites: Efficiency, Stability, Mechanism, and Degradation Pathway

Abstract

Tungsten trioxide and cuprous oxide composites were successfully prepared by the solvothermal and coprecipitation method. The obtained composites were comprehensively characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Raman, and PL spectroscopy. The Cu2O@WO3/PS system was developed to degrade norfloxacin (NOR) in an aqueous solution. The photodegradation experiments and electrochemical characterization (EIS and photocurrent curves) showed that Cu2O@WO3(2–1) exhibited optimal photocatalytic activity under visible light. Furthermore, the sulfate radical was corroborated to play a predominant role in the photodegradation process, and the possible free radical formation mechanism was put forward. Density functional theory (DFT) calculation and LC-MS were utilized to investigate the intermediates during NOR degradation, and three possible degradation pathways were elucidated. Ecotoxicity analysis by TEST showed that the toxicity of these intermediates was generally weaker than parent NOR. Moreover, the synthetic sample was authenticated to possess good stability and repeatability. This work provided the guidance for available and applicable utilization of persulfate photocatalytic activation technology in pharmaceutical wastewater purification.

Study on the degradation and metabolic mechanism of four quinolone antibiotics by mixed strains

“…strain isolated from a wastewater treatment plant. The formation of another direct product of NOR oxidation (product 1) appears to take place via the addition of an oxygen atom that produces the hydroxy-derivative of piperazine ring, indicating that the degradation pathway of NOR in this article is similar to it (Liu et al, 2012;Cai et al, 2022).…”