Tang Qian, Zhu Liangwen, Wang Qing, Deng Lin, Hu Jun, Singh Rajendra Prasad
Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China.
Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China.
J Environ Manage. 2023 Dec 15;348:119225. doi: 10.1016/j.jenvman.2023.119225. Epub 2023 Oct 11.
LED-UV/chlorine is a promising alternative disinfection technology that emits mono-wavelength light for high germicidal efficiency. Halonitromethanes (HNMs) are highly cytotoxic and genotoxic disinfection byproducts that can be formed during LED-UV/chlorine disinfection. Thus, this work aimed to investigate the HNMs formation from glycine (Gly) during LED-UV/chlorine disinfection. The results indicated that the concentrations of chlorinated-HNMs (Cl-HNMs) increased first and then decreased as the reaction proceeded. Besides, the effects of operating parameters (UV intensity, free chlorine dosage, and pH) and coexisting ions (Cu and Br) on HNMs formation were investigated. It was found that the formation concentrations of Cl-HNMs increased with the increase of LED-UV intensity and free chlorine dosage but decreased with increased pH. The presence of Cu promoted the formation of Cl-HNMs. The total concentration of HNMs (at 3 min) with adding 1.5 mg/L Cu was 30.90% higher than that without Cu. Notably, nine species of HNMs were detected after adding Br, and the total concentrations of HNMs were enhanced. Moreover, Cl-HNMs were gradually transformed into brominated (chlorinated)-HNMs and brominated-HNMs as Br concentration increased. According to the findings, the possible formation mechanism of HNMs from Gly during LED-UV/chlorine disinfection was deduced. Finally, it was demonstrated that the formation laws of HNMs from Gly in real water samples were basically consistent with those in simulated water. Insights obtained in this study help to comprehend the HNMs formation from Gly and provide strategies for controlling the production of HNMs during LED-UV/chlorine disinfection.
LED-UV/氯是一种很有前景的替代消毒技术，它发射单波长光以实现高效杀菌。卤代硝基甲烷（HNMs）是具有高细胞毒性和遗传毒性的消毒副产物，可在LED-UV/氯消毒过程中形成。因此，本研究旨在探究LED-UV/氯消毒过程中甘氨酸（Gly）生成HNMs的情况。结果表明，随着反应进行，氯化-HNMs（Cl-HNMs）的浓度先升高后降低。此外，研究了操作参数（UV强度、自由氯剂量和pH值）以及共存离子（Cu和Br）对HNMs生成的影响。结果发现，Cl-HNMs的生成浓度随LED-UV强度和自由氯剂量的增加而增加，但随pH值的升高而降低。Cu的存在促进了Cl-HNMs的生成。添加1.5 mg/L Cu时，HNMs的总浓度（3分钟时）比不添加Cu时高30.90%。值得注意的是，添加Br后检测到9种HNMs，且HNMs的总浓度有所提高。此外，随着Br浓度的增加，Cl-HNMs逐渐转化为溴化（氯化）-HNMs和溴化-HNMs。根据研究结果，推导了LED-UV/氯消毒过程中Gly生成HNMs的可能机制。最后，证明了实际水样中Gly生成HNMs的规律与模拟水样中的基本一致。本研究获得的见解有助于理解Gly生成HNMs的过程，并为控制LED-UV/氯消毒过程中HNMs的产生提供策略。
