ABSTRACT

The photocatalytic reduction of methylene blue was recognized as an economical and effective way for dye removal. To enhance photocatalytic activity under visible-light condition, fluorine and graphene synergistically modified TiO₂ (F-TiO₂/rGO) nanocomposites were successfully prepared by sol–gel method. Characterization results showed F ions played an essential role in the formation of TiO₂ nanoparticles. Between the fluorine sources selected, NH₄F was more optimal than NaF doping on the grounds that the existence of Na⁺ ion was an inevitable factor for the production of brookite. F-TiO₂/rGO nanocomposite obtained by adding 5%at NH₄F significantly narrowed the bandgap energy from approximately 3.17 to 2.41 eV. Box–Behnken design was adopted to optimize the MB photo-degradation process by F_(5%NH4F)-TiO₂/rGO nanocomposites under different reaction conditions. Moreover, the antibacterial behaviour of this novel material was also investigated by Escherichia coli (E. coli) bacteria under visible light. The morphology changes of E. coli cells were directly observed by field emission scanning electron microscope and further confirmed that the excellent sterilization of F-TiO₂/rGO nanocomposites resulted from the active species. The outstanding photocatalytic performance and antibacterial behaviour of F-TiO₂/rGO nanocomposite was attributed to the synergistic effect of photocatalytic redox reaction and adsorption. These results indicated F_(5%NH4F)-TiO₂/rGO nanocomposite was a promising antibacterial photo-adsorbent for wastewater treatment improvement.

 抽象的

光催化还原亚甲基蓝被认为是一种经济有效的染料去除方法。为了增强可见光条件下的光催化活性，采用溶胶-凝胶法成功制备了氟和石墨烯协同修饰的TiO ₂ (F-TiO ₂ /rGO)纳米复合材料。表征结果表明F离子在TiO ₂纳米颗粒的形成中发挥着重要作用。在选择的氟源中，NH ₄ F比NaF掺杂更优，因为Na ⁺离子的存在是板钛矿生成的必然因素。通过添加5％NH ₄ F获得的F-TiO ₂ /rGO纳米复合材料显着地将带隙能量从大约3.17 eV缩小到2.41 eV。采用Box-Behnken设计优化了F _(5%NH4F) -TiO ₂ /rGO纳米复合材料在不同反应条件下的MB光降解过程。此外，还通过大肠杆菌（E. coli）细菌在可见光下研究了这种新型材料的抗菌行为。通过场发射扫描电子显微镜直接观察大肠杆菌细胞的形态变化，进一步证实F-TiO ₂ /rGO纳米复合材料的优异灭菌效果是活性物种的结果。 F-TiO ₂ /rGO纳米复合材料优异的光催化性能和抗菌行为归因于光催化氧化还原反应和吸附的协同作用。 这些结果表明F _(5%NH4F) -TiO ₂ /rGO纳米复合材料是一种有前途的用于改善废水处理的抗菌光吸附剂。