|Title||Photocatalytic inactivation of Escherichia coli by natural sphalerite suspension: Effect of spectrum, wavelength and intensity of visible light|
Yip, Ho Yin
|Affiliation||Chinese Univ Hong Kong, Sch Life Sci, Shatin, Hong Kong, Peoples R China.|
Peking Univ, Sch Earth & Space Sci, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China.
Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Organ Geochem, Guangzhou 510640, Guangdong, Peoples R China.
Peking Univ, Shenzhen Grad Sch, Sch Environm & Energy, Shenzhen 518055, Peoples R China.
|Abstract||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 8 h 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. (C) 2011 Elsevier Ltd. All rights reserved.|
|Appears in Collections:||地球与空间科学学院|