Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada.
Photochem Photobiol. 2010 Jan-Feb;86(1):176-81. doi: 10.1111/j.1751-1097.2009.00640.x. Epub 2009 Nov 12.
The efficacy of UV and vacuum-UV (VUV) disinfection of Bacillus subtilis spores in aqueous suspensions at wavelengths of 172, 222 and 254 nm was evaluated. A Xe(2)* excilamp, a KrCl* excilamp and a low-pressure mercury lamp were used as almost monochromatic light sources at these three wavelengths. The first-order inactivation rate constants at 172, 222 and 254 nm were 0.0023, 0.122 and 0.069 cm(2) mJ(-1), respectively. Therefore, a 2 log reduction of B. subtilis spores was reached with fluences (UV doses) of 870, 21.6 and 40.4 mJ cm(-2) at these individual wavelengths. Consequently, for the inactivation of B. subtilis spores, VUV exposure at 172 nm is much less efficient than exposure at the other two wavelengths, while exposure at 222 nm is more efficient than that at 254 nm, which is probably because triplet energy transfer from DPA to thymine bases at 222 nm is higher than that at 254 nm. This research indicated quantitatively that VUV light is not practicable for microorganism disinfection in water and wastewater treatment. However, in comparison with other advanced oxidation processes (e.g. UV/TiO(2), UV/H(2)O(2) or O(3)/H(2)O(2)) the VUV-initiated photolysis of water is likely more efficient in generating hydroxyl radicals and more effective for the inactivation of microorganisms.
评价了在 172、222 和 254nm 波长下，UV 和真空紫外（VUV）对芽孢杆菌孢子在水悬浮液中的消毒效果。使用 Xe(2)* 外激灯、KrCl* 外激灯和低压汞灯作为这三个波长的几乎单色光源。在 172、222 和 254nm 下的一级失活动力常数分别为 0.0023、0.122 和 0.069cm(2)mJ(-1)。因此，在这些单个波长下，芽孢杆菌孢子的 2 对数减少需要 870、21.6 和 40.4mJcm(-2)的剂量（UV 剂量）。因此，对于芽孢杆菌孢子的失活，172nm 的 VUV 暴露比在其他两个波长下的暴露效率要低得多，而 222nm 的暴露比 254nm 的暴露效率要高，这可能是因为在 222nm 时，DPA 到胸腺嘧啶碱基的三重态能量转移比在 254nm 时要高。这项研究定量表明，VUV 光在水处理中对微生物的消毒不可行。然而，与其他高级氧化工艺（如 UV/TiO(2)、UV/H(2)O(2) 或 O(3)/H(2)O(2)）相比，VUV 引发的水光解可能更有效地生成羟基自由基，对微生物的失活更有效。
