Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China.
Chemosphere. 2019 Feb;217:869-878. doi: 10.1016/j.chemosphere.2018.11.072. Epub 2018 Nov 13.
A visible-light-driven and magnetic photocatalyst Ag/Fe,N-TiO/FeO@SiO (AgFeNTFS) was synthesized through a multi-step method. AgFeNTFS was tested for the photocatalytic disinfection of Escherichia coli (E. coli) and degradation of bisphenol A (BPA) under visible light irradiation, separately and simultaneously. The results showed that a 6.3-log reduction in cell density of E. coli was achieved and BPA (2 mg/L) was completely removed by AgFeNTFS in the separated photocatalytic processes within 120 min. In the simultaneous process, the photocatalytic disinfection of E. coli was not influenced in the presence of BPA, but the efficiency of BPA degradation was dropped by 10%. This was likely due to the competition for the same dominant reactive species of O and HO between E. coli and BPA in the simultaneous process, as evidenced by the scavenger study and the interactions between the pollutants and AgFeNTFS. Moreover, the simultaneous photocatalytic activity of E. coli disinfection and BPA degradation by AgFeNTFS was investigated in the sewage obtained from a local wastewater treatment plant. The photocatalysis treated sewage could meet with the local disinfection discharge standard with a 3-log reduction of E. coli after 90 min, and a complete removal of BPA was achieved simultaneously after 360 min. Moreover, AgFeNTFS showed high magnetic separation efficiency and had a good reusability over three cycles for the simultaneous photocatalytic disinfection and degradation of BPA in both synthetic water and sewage. This study provides insights on the application of a reusable magnetic photocatalyst for simultaneous disinfection and degradation of BPA in sewage.
一种可见光驱动的磁性光催化剂 Ag/Fe,N-TiO/FeO@SiO（AgFeNTFS）通过多步方法合成。分别和同时在可见光照射下，测试了 AgFeNTFS 对大肠杆菌（E. coli）的光催化消毒和双酚 A（BPA）的降解性能。结果表明，AgFeNTFS 在分离光催化过程中，大肠杆菌的细胞密度降低了 6.3log，2mg/L 的 BPA 在 120min 内完全去除。在同时过程中，BPA 的存在并没有影响大肠杆菌的光催化消毒，但 BPA 降解效率下降了 10%。这可能是由于在同时过程中，O 和 HO 等主导活性物种在大肠杆菌和 BPA 之间存在竞争，这一点可以通过猝灭实验和污染物与 AgFeNTFS 之间的相互作用得到证明。此外，还研究了 AgFeNTFS 对当地污水处理厂污水中大肠杆菌消毒和 BPA 降解的同时光催化活性。经过 90min 的光催化处理后，污水中的大肠杆菌减少了 3log，达到了当地消毒排放标准，同时经过 360min 的处理后，BPA 被完全去除。此外，AgFeNTFS 在合成水和污水中同时光催化降解 BPA 的三个循环中表现出较高的磁分离效率和良好的可重复使用性。本研究为可重复使用的磁性光催化剂在污水中同时消毒和降解 BPA 的应用提供了新的思路。
