School of Life Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
Chemosphere. 2011 Aug;84(9):1276-81. doi: 10.1016/j.chemosphere.2011.05.055. Epub 2011 Jun 22.
The photocatalytic disinfection of Escherichia coli K-12 is investigated by the natural sphalerite (NS) under different spectra, wavelengths and intensities of visible light (VL) emitted by light-emitting-diode lamp (LED). The spectrum effect of VL on disinfection efficiency is studied by using white LED, fluorescent tube (FT) and xenon lamp (XE), which indicates that the "discreted peak spectrum" of FT is more effective to inactivate bacteria than "continuous spectrum" of LED and XE. Besides, the photocatalytic disinfection of bacteria is compared under different single spectrum (blue, green, yellow and red color) LEDs. The results show that the most effective wavelength ranges of VL for photocatalytic disinfection with the NS are 440-490 and 570-620 nm. Furthermore, a positive relationship is obtained between the disinfection efficiency and the VL intensity. The experiment shows that NS can completely inactivate 10(7)cfu mL(-1)E. coli K-12 within 8h irradiation by white LED with the intensity of 200 mW cm(-2) at pH 8. Moreover, the destruction process of the cell wall and the cell membrane are directly observed by TEM. Finally, no bacterial colony can be detected within a 96 h regrowth test of inactivated bacteria, which reveals that the VL-photocatalytic disinfection leads to an irreversible damage to the bacterial cells.
采用发光二极管（LED）发出的不同光谱、波长和强度的可见光（VL）对大肠杆菌 K-12 进行了光催化消毒研究。通过使用白色 LED、荧光灯管（FT）和氙灯（XE）研究了 VL 对消毒效率的光谱效应，结果表明 FT 的“离散峰光谱”比 LED 和 XE 的“连续光谱”更有效地灭活细菌。此外，还比较了不同单光谱（蓝色、绿色、黄色和红色）LED 下的细菌光催化消毒效果。结果表明，VL 对 NS 进行光催化消毒的最有效波长范围为 440-490nm 和 570-620nm。此外，消毒效率与 VL 强度呈正相关关系。实验表明，在 pH8 条件下，强度为 200mW/cm²的白色 LED 辐照 8h 即可完全灭活 10(7)cfu/mL 的大肠杆菌 K-12。此外，还通过 TEM 直接观察到细胞壁和细胞膜的破坏过程。最后，在失活细菌的 96h 再生试验中未检测到细菌菌落，这表明 VL-光催化消毒会导致细菌细胞不可逆的损伤。
