CuFeO_(2)@PVP的制备及其基于光电芬顿降解氧氟沙星

Preparation of CuFeO_(2)@PVP for the photo-electro-Fenton degradation of ofloxacin

以聚乙烯吡咯烷酮作为改性剂,利用水热法合成了表面具有丰富氧空位的CuFeO_(2)@PVP复合催化剂。通过XRD、FT-IR、SEM、TEM和EPR等方法证实了催化剂的成功合成及确定了催化剂的形貌和微观结构。采用UV-vis DRS、PL、EIS和IT等方法证实了CuFeO_(2)@PVP比CuFeO_(2)具有更好的光学性能及光电性能。不同体系下的降解实验结果表明,CuFeO_(2)@PVP的光电催化活性比纯相CuFeO_(2)有明显的提升,反应速率是纯相CuFeO_(2)的1.79倍,去除率相比于单独的吸附、阳极氧化、光催化、电催化和电芬顿体系分别提高了87.9%、68.2%、67.3%、67%和9.8%,说明可见光、电场和异相催化剂间存在协同效应。进一步探究了催化剂投加量、电流密度、溶液pH、共存离子种类对异相光电芬顿体系降解氧氟沙星(OFX)的影响。结果表明,在最佳催化剂投加量为0.4 g/L、最佳电流密度为4 mA/cm^(2)的条件下,CuFeO_(2)@PVP光电Fenton体系在120 min时对10 mg·L^(-1)OFX的降解率达到94.3%。pH在5-9之间时对OFX的降解呈现抑制作用,pH在3-3.6之间时降解效果基本持平。溶液中的Cl-对OFX的降解起到轻微的促进作用,而NO_(3)^(-)、PO_(4)^(3-)和CO_(3)^(2-)会抑制体系对OFX的降解。此外,5次循环降解实验后,CuFeO_(2)@PVP的降解效率降低了13.8%,表明其具有良好的稳定性。自由基淬灭实验和电子顺磁共振结果表明·OH是最主要的活性自由基并基于上述结果推测出可能的降解机理。

The CuFeO_(2)@PVP catalyst with rich oxygen vacancies was synthesized via a simple one-step hydrothermal method with polyvinylpyrrolidone as modifier. The successful synthesis of the catalyst and its morphology and microstructure were confirmed by XRD, FT-IR, SEM, TEM and EPR methods. UV-vis DRS,PL, EIS and IT were used to confirmed that CuFeO_(2)@PVP has better photocatalytic activity and photoelectrochemical properties than CuFeO_(2). The results of degradation experiments with different systems showed that the degradation efficiency by CuFeO_(2)@PVP in photo-electro-Fenton system increased significantly,which was 1.79 times as much as pure CuFeO_(2). The removal rate by photo-electro-Fenton system was 66.8%,66.5% and 9.3% higher than photocatalysis, electrocatalysis and electro Fenton system, respectively, which indicated that there was a synergistic effect among the visible light, electro and heterogeneous catalyst. The effects of catalyst dosage, current density, solution pH values and coexistence ions on the degradation of OFX were further discussed. The removal rate for 10 mg·L^(-1)OFX was 94.3% after 120 min oxidation at catalyst dosage of 0.4 g·L^(-1)and current density of 4 mA/cm~2. At pH 5-9, OFX degradation was inhibited, while at pH 3-3.6, the degradation was almost unchanged. Cl-had a slight acceleration effect on OFX degradation, while NO_(3)^(-),PO_(4)^(3-)and CO_(3)^(2-)inhibited the reaction. In addition, the degradation efficiency of CuFeO_(2)@PVP decreased by 13.8% after 5 cyclic degradation experiments, indicating that it has good stability. The results of radical quenching experiment and electron paramagnetic resonance showed that ·OH was the main active radical, and the possible degradation mechanism was inferred based on the above results.