CuO Rich In Oxygen Vacancies Fenton-like Oxidation Of Ciprofloxacin: Degradation Mechanism And Toxicity

In recent years,Fenton-like oxidation technology with H₂O₂ activated by transition metal oxides has gradually become a hot spot in water pollution control research.Among these transition metal oxides,copper oxide（CuO）has attracted much attention due to its low price,ecological friendliness,high specific sur face area and chemical stability.Although extensive studies have confirmed that CuO shows excellent reactivity in Fenton-like reactions,but it is still limited by the conversion rate of Cu²⁺/Cu⁺,and the catalytic mechanism also needs to be further studi ed.In this study,different Mn content was introduced into CuO lattice by co-precipitation method,and an oxygen vacancy（OVs）assisted Fenton-like catalyst Mn₁₀CuO/OVs was successfully prepared.Ciprofloxacin was used as the target pollutant to explore the catalytic mechanism and environmental risks of Mn₁₀CuO/OVs/H₂O₂ system.The results of FTIR,SEM,BET and XPS analysis showed that CuO and its modified products with good crystallinity can be easily prepared by coprecipitation method.The incorporation of Mn formed the Mn-O-Cu-O-Mn coupling without changing the lattice of CuO,but improves the surface properties of CuO.The specific surface area of M n₁₀CuO(78.92 m²g^-1)was significantly higher than that of CuO(34.58 4 m²g^-1),and ESR test verified that the OVs was successfully constructed by Mn doping.The Mn₁₀CuO/OVs/H₂O₂ Fenton-like system has high buffering ability against p H of ciprofloxacin solution,thus creating suitable reaction conditions,and show ed excellent performance in a wide p H range（p H=3～10）.When H₂O₂ concentration=60 mmol/L,catalyst Mn₁₀CuO dosage=1.0 g/L,and under natural p H,the degradation rate of ciprofloxacin（10 mg/L）reached 83%after 90min,which was attributed to the formation of OVs and Cu-Mn binary synergism after Mn addition.It not only improved the surface properties of the catalyst,but also promote d the activation of H₂O₂.The capture experiment,XPS and other series of analysis showed that≡Cu³⁺played a critical role in the degradation of ciprofloxacin,·OH,·O₂^-and ¹O₂played a minor role,and the antibacterial activity of the degraded ciprofloxacin was significantly decreased.At the same time,toxicity test proved that neither the metal ions leached during the reaction nor the reaction intermediates could not inhibit the germination of alfalfa,indicating that the system had no potential environmental risk.Moreover,Mn₁₀CuO/OVs/H₂O₂ Fenton-like system can also degrade 20 mg/L tetracycline and oxytetracycline effectively,and work in different water samples（i.e.,tap water,river water and lake water）without adjusting p H,manifesting that this system has the potential of practical application and is a feasible treatment method of antibiotic wastewater.