Xu Jiale, Huang Ching-Hua
Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58102, United States.
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Environ Sci Technol Lett. 2023 May 26;10(6):543-548. doi: 10.1021/acs.estlett.3c00313. eCollection 2023 Jun 13.
Krypton chloride (KrCl*) excilamps emitting at far-UVC 222 nm represent a promising technology for microbial disinfection and advanced oxidation of organic micropollutants (OMPs) in water treatment. However, direct photolysis rates and photochemical properties at 222 nm are largely unknown for common OMPs. In this study, we evaluated photolysis for 46 OMPs by a KrCl* excilamp and compared it with a low-pressure mercury UV lamp. Generally, OMP photolysis was greatly enhanced at 222 nm with fluence rate-normalized rate constants of 0.2-21.6 cm·μEinstein, regardless of whether they feature higher or lower absorbance at 222 nm than at 254 nm. The photolysis rate constants and quantum yields were 10-100 and 1.1-47 times higher, respectively, than those at 254 nm for most OMPs. The enhanced photolysis at 222 nm was mainly caused by strong light absorbance for non-nitrogenous, aniline-like, and triazine OMPs, while notably higher quantum yield (4-47 times of that at 254 nm) occurred for nitrogenous OMPs. At 222 nm, humic acid can inhibit OMP photolysis by light screening and potentially by quenching intermediates, while nitrate/nitrite may contribute more than others to screen light. Overall, KrCl* excilamps are promising in achieving effective OMP photolysis and merit further research.
发射远紫外线222纳米的氪氯化物（KrCl*）准分子灯是一种很有前景的技术，可用于微生物消毒以及水处理中有机微污染物（OMPs）的高级氧化。然而，常见OMPs在222纳米处的直接光解速率和光化学性质在很大程度上尚不清楚。在本研究中，我们通过KrCl准分子灯评估了46种OMPs的光解，并将其与低压汞紫外灯进行了比较。一般来说，无论OMPs在222纳米处的吸光度高于还是低于254纳米，其在222纳米处的光解都大大增强，通量率归一化速率常数为0.2-21.6厘米·微爱因斯坦。对于大多数OMPs，其光解速率常数和量子产率分别比在254纳米处高10-100倍和1.1-47倍。222纳米处光解增强主要是由于非含氮、苯胺类和三嗪类OMPs的强光吸收，而含氮OMPs的量子产率则显著更高（是254纳米处的4-47倍）。在222纳米处，腐殖酸可通过光屏蔽以及可能通过淬灭中间体来抑制OMPs光解，而硝酸盐/亚硝酸盐在光屏蔽方面的作用可能比其他物质更大。总体而言，KrCl准分子灯在实现有效的OMPs光解方面很有前景，值得进一步研究。
