从光催化剂构效关系与细菌响应机制双重视角,探讨了Ag掺杂比例调控对CoP/CNx复合光催化剂抗菌性能的影响.采用光沉积法构建Ag/CoP/CNx复合材料,采用X射线衍射、透射电子显微镜及紫外可见漫反射光谱等手段对其晶体结构、形貌与光学性能进行系统表征.结果表明,Ag的引入增强了光生载流子分离效率,从而提高了光催化活性.当Ag掺杂质量分数为2%,大肠杆菌初始浓度为104CFU/mL时,催化剂于20min内可实现大肠杆菌的完全灭活.在4次循环实验中,其杀菌率仍保持在100%、99.99%、98.60%和97.51%,显示出优异的稳定性.自由基猝灭实验表明,空穴(h+)为主导活性物种,超氧自由基(×O2-)为次要活性物种,加入捕获剂后灭菌率分别下降至71.9%和23.7%. 同时,K+释放浓度由2.64mg/L升至5.47mg/L (CoP/CNx)和7.30mg/L (Ag-CoP/CNx).扫描电镜与傅里叶变换红外光谱分析表明,空穴和超氧自由基破坏细胞膜结构,导致胞内物质泄漏并进一步穿透细胞,引发DNA与蛋白质等生物大分子的氧化损伤.研究结果为Ag基纳米复合光催化剂在污水处理与环境消毒等领域的应用提供理论基础与技术支 持.
Abstract
The influence of Ag doping ratio on the antibacterial properties of CoP/CNx composite photocatalysts was studied from dual perspectives: photocatalyst structure-activity relationships and bacterial response mechanisms. Ag/CoP/CNx composite materials were fabricated using the photodeposition method. The crystal structure, morphology and optical properties were systematically characterized through X-ray diffraction, transmission electron microscopy, and UV-visible diffuse reflectance spectroscopy. The separation efficiency of photogenerated carriers was enhanced when Ag was introduced, which resulted in improved photocatalytic activity. Complete E. coli inactivation was accomplished within 20minutes when 2wt% Ag doping was employed with an initial bacterial concentration of 104CFU/mL. The bactericidal efficiency was sustained at 100%, 99.99%, 98.60%, and 97.51% over four successive cycles, whereby remarkable stability was demonstrated. Through free radical quenching experiments, holes (h+) were determined to be the dominant active species, while superoxide radicals (·O2-) were identified as secondary active species. The sterilization efficiency was decreased to 71.9% and 23.7% after radical scavenger were introduced, respectively. The K+ release concentration was elevated from 2.64mg/L to 5.47mg/L (CoP/CNx) and 7.30mg/L (Ag-CoP/CNx). The destruction of cell membrane structures was verified by scanning electron microscopy and Fourier transform infrared spectroscopy analyses. This damage was induced by holes and superoxide radicals, whereby intracellular contents were leaked. Cell penetration was subsequently observed, oxidative damage to biomolecules, including DNA and proteins, was triggered. The research findings were established as theoretical and technical foundations for the implementation of Ag-based nanocomposite photocatalysts in wastewater treatment and environmental disinfection applications.
关键词
光催化 /
大肠杆菌 /
灭活机制 /
抗菌性能
Key words
photocatalysis /
Escherichia coli /
inactivation /
antibacterial properties
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基金
国家重点研发计划(2023YFC3708203);西安市科技局社会发展科技创新示范项目(24SFSF0007)
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