Effective Photocatalytic Disinfection of E. coli K-12 Using AgBr-Ag-Bi2WO6 Nanojunction System Irradiated by Visible Light: The Role of Diffusing Hydroxyl Radicals
Effective Photocatalytic Disinfection of E. coli K-12 Using AgBr-Ag-Bi2WO6 Nanojunction System Irradiated by Visible Light: The Role of Diffusing Hydroxyl Radicals
复制标题
DOI：
10.1021/es903087w
复制
发表时间：
2010-02-15
影响因子：
11.4
通讯作者：
Wong, Po-Keung
中科院分区：
文献类型：
--
作者：
Zhang, Li-Sha;Wong, Kin-Hang;Wong, Po-Keung
迫切需要开发有效和低成本的消毒技术，以解决有害微生物爆发造成的问题。在这项工作中，我们报告了一种有效的光催化消毒的E。coliK-12中，在可见光（λ ≥ 400 nm）照射下，使用AgBr-Ag-Bi 2 WO 6纳米结体系作为催化剂。可见光驱动的AgBr-Ag-Bi 2 WO 6纳米结可完全降解5 × 10（7）cfu mL（-1）E. coliK-12，在15 min内降解率达到上级，优于Bi_2WO_6超结构、Ag-Bi_2 WO_6和AgBr-Ag-TiO_2复合物等VLD光催化剂。此外，通过使用不同的清除剂，AgBr-Ag-Bi 2 WO 6纳米结的杀菌作用的光化学机制进行了研究。结果表明，氧化途径和还原途径产生的扩散羟基自由基在光催化消毒中起着重要作用。此外，AgBr-Ag-Bi 2 WO 6纳米结与细菌细胞之间的直接接触对于光催化消毒E. coli K-12。最后，通过TEM图像直接观察到细菌细胞的光催化破坏，并通过测定被杀死的细菌的钾离子（K+）泄漏进一步证实。本工作为AD光催化剂提供了一种潜在的有效的消毒细菌细胞，甚至破坏生物膜，可以为微生物提供庇护和基质，并抵抗消毒。
Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi2WO6 nanojunction system as a catalyst under visible light (lambda >= 400 nm) irradiation. The visible-light-driven (VLD) AgBr-Ag-Bi2WO6 nanojunction could completely inactivate 5 x 10(7) cfu mL(-1) E. coli K-12 within 15 min, which was superior to other VLD photocatalysts such as Bi2WO6 superstructure, Ag-Bi2WO6 and AgBr-Ag-TiO2 composite. Moreover, the photochemical mechanism of bactericidal action for the AgBr-Ag-Bi2WO6 nanojunction was investigated by using different scavengers. It was found that the diffusing hydroxyl radicals generated both by the oxidative pathway and the reductive pathway play an important role in the photocatalytic disinfection. Moreover, direct contact between the AgBr-Ag-Bi2WO6 nanojunction and bacterial cells was not necessary for the photocatalytic disinfection of E. coli K-12. Finally, the photocatalytic destruction of the bacterial cells was directly observed by TEM images and further confirmed by the determination of potassium ion (K+) leakage from the killed bacteria. This work provides a potential effective AD photocatalyst to disinfect the bacterial cells, even to destruct the biofilm that can provide shelter and substratum for microorganisms and resist to disinfection.