物理化学学报 >> 2025, Vol. 41 >> Issue (9): 100105.doi: 10.1016/j.actphy.2025.100105

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S型异质结g-C3N4/Bi2WO6高效降解左氧氟沙星:性能、机理及降解路径

韦梦兰, 欧晓霞*(), 王艺濛, 张梦圆, 滕飞, 王凯旋   

  1. 大连民族大学环境与资源学院, 辽宁 大连 116600
  • 收稿日期:2025-03-05 修回日期:2025-05-09 录用日期:2025-05-12 发布日期:2025-07-04
  • 通讯作者: Email: ouxiaoxia@dlnu.edu.cn (欧晓霞)
  • 基金资助:
    辽宁省科技计划联合项目(2023JH2/101800001); 辽宁省教育厅基础科研基金(LJKMZ20220396); 大连市科技人才创新支持政策实施计划(2024RQ056)

S-scheme heterojunction g-C3N4/Bi2WO6 highly efficient degradation of levofloxacin: performance, mechanism and degradation pathway

Menglan Wei, Xiaoxia Ou*(), Yimeng Wang, Mengyuan Zhang, Fei Teng, Kaixuan Wang   

  1. College of Environment and Resources, Dalian Minzu University, Dalian 116600, Liaoning Province, China
  • Received:2025-03-05 Revised:2025-05-09 Accepted:2025-05-12 Published:2025-07-04
  • Contact: Email: ouxiaoxia@dlnu.edu.cn (Xiaoxia Ou)
  • Supported by:
    the Liaoning Provincial Science and Technology Program Joint Plan(2023JH2/101800001); the Basic Scientific Research Fund of Liaoning Provincial Education Department(LJKMZ20220396); Dalian Science and Technology Talents Innovation Support Program(2024RQ056)

摘要:

采用一步水热法合成了g-C3N4/Bi2WO6(MCN/BWO)异质结光催化剂,用于降解左氧氟沙星(LEV)。在模拟太阳光照射下,摩尔比为1 : 1的MCN/BWO对LEV的降解率达到98.14%,这归因于MCN和BWO之间形成了S型异质结。原位XPS分析和表面功函数测量证实了电子转移路径遵循S型异质结机制。MCN/BWO体系中S型异质结产生的内建电场(IEF)促进了光生电子(e−)从BWO的导带(CB)直接转移到MCN的价带(VB)。这一过程实现了光生电子-空穴对(e−-h+)的有效分离,h⁺在BWO的VB上积累,e−在MCN的CB上积累。自由基捕获实验表明,超氧自由基(·O₂−)和h⁺是主要的活性物种。除了表现出优异的光催化性能外,该催化剂在连续三个循环中保持了良好的稳定性。为了阐明降解机制,采用液相色谱-质谱(LC-MS)和定量构效关系(QSAR)分析来鉴定降解途径、中间产物和潜在毒性。本研究为废水处理应用提供了理论基础。

关键词: S型异质结, MCN/BWO, 光催化, 左氧氟沙星, 降解路径

Abstract:

g-C3N4/Bi2WO6 (MCN/BWO) heterojunction photocatalysts were synthesized via a one-step hydrothermal method for the degradation of levofloxacin (LEV). Under simulated sunlight irradiation, the degradation rate of LEV by MCN/BWO with a molar ratio of 1 : 1 reached 98.14%, which was attributed to the formation of an S-scheme heterojunction between MCN and BWO. In situ XPS analysis and surface work function measurements confirmed that the electron transfer pathway follows the S-scheme heterojunction mechanism. The internal electric field (IEF) generated by the S-scheme heterojunction in the MCN/BWO system facilitates direct transfer of photogenerated electrons (e−) from the conduction band (CB) of BWO to the valence band (VB) of MCN. This process enables efficient separation of photogenerated electron-hole (e−-h+) pairs, with h⁺ accumulating on the VB of BWO and e− accumulating on the CB of MCN. Free radical trapping experiments demonstrated that the superoxide free radical (·O₂−) and h⁺ were the primary active species. Besides exhibiting superior photocatalytic performance, the catalyst maintained excellent stability over three consecutive cycles. To elucidate the degradation mechanism, liquid chromatography-mass spectrometry (LC-MS) and quantitative structure-activity relationship (QSAR) analysis were employed to identify degradation pathways, intermediates, and potential toxicity. This study provides a theoretical foundation for wastewater treatment applications.

Key words: S-scheme heterojunction, MCN/BWO, Photocatalysis, Levofloxacin, Degradation pathway