Superior disinfection effect of Escherichia coli by hydrothermal synthesized TiO2-based composite photocatalyst under LED irradiation: Influence of environmental factors and disinfection mechanism
Superior disinfection effect of Escherichia coli by hydrothermal synthesized TiO2-based composite photocatalyst under LED irradiation: Influence of environmental factors and disinfection mechanism
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DOI：
10.1016/j.envpol.2019.01.082
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发表时间：
2019-04-01
影响因子：
8.9
通讯作者：
Yang, Yingnan
中科院分区：
文献类型：
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作者：
Liu, Na;Zhu, Qi;Yang, Yingnan
采用P/Ag/Ag2O/Ag3PO4/TiO2光催化剂对发光二极管(LED)照射下的大肠杆菌进行光催化灭活，以考察其光催化杀菌活性。结果表明，该复合光催化剂具有显著的杀菌能力，在最佳催化剂载量为0.5g/L的条件下，在40min内即可完全灭活10(8)cfu/mL的大肠杆菌。考察了光波长、光照强度、温度、溶液pH和无机离子等环境因素对灭活效果的影响。结果表明，在蓝光LED照射、光照强度为750W/m(2)、温度在30~37℃、pH值在自然或弱碱性条件下，P/Ag/Ag2O/Ag3PO4/TiO2光催化灭菌效果较好。在正常环境水平下，不同无机离子的存在对杀菌性能无明显影响。此外，在灭活过程中，用扫描电子显微镜(SEM)直接观察了大肠杆菌细胞的形态变化，并通过对灭活后的大肠杆菌K+渗漏的测定进一步证实了这一点。结果表明，光催化失活对细菌细胞膜造成了严重的损伤。结果表明，P/Ag/Ag2O/Ag3PO4/TiO2光催化灭菌的主要反应物种是H(+)和中心点O-2(-)，而不是由于Ag+的渗漏(
The photocatalytic inactivation of Escherichia coli (E. coli) under light-emitting diode (LED) light irradiation was performed with P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst to investigate the photocatalytic bactericidal activity. Our work showed that this composite photocatalyst possessed remarkable bacterial disinfection ability and could completely inactivate 10(8) cfu/mL of E. coli within just 40 min under the optimum catalyst loading of 0.5 g/L. The effects of different environmental factors, including light wavelength, light intensity, temperature, solution pH and inorganic ions, on the inactivation efficiency were evaluated. The results showed that bacteria inactivation by P/Ag/Ag2O/Ag3PO4/TiO2 was more favorable with blue colored LED irradiation, light intensity at 750 W/m(2), temperature in the range of 30-37 degrees C and pH values at natural or slightly alkaline condition. The existence of different inorganic ions under normal environmental level had no significant impact on the bactericidal performance. In addition, during the inactivation process, the morphology changes of E. coli cells were directly observed by scanning electron microscope (SEM) and further proved by the measurement of K+ leakage from the inactivated E. coli. The results demonstrated that the photocatalytic inactivation caused drastic damage on bacterial cells membrane. Furthermore, the mechanisms of photocatalytic bacterial inactivation were also systemically studied and the results confirmed that the excellent disinfection activity of P/Ag/Ag2O/Ag3PO4/TiO2 resulted from the major reactive species: h(+) and center dot O-2(-) from photocatalytic process instead of the leakage of Ag+ (