化学
亚硝酸盐
过硫酸盐
活性氮物种
有机质
环境化学
溴酸盐
一氧化氮
有机化学
硝酸盐
溴化物
催化作用
作者
Lingjun Bu,Julong Sun,Yangtao Wu,Weiqiu Zhang,Xiaodi Duan,Shiqing Zhou,Dionysios D. Dionysiou,John C. Crittenden
出处
期刊:Water Research
[Elsevier]
日期:2020-01-01
卷期号:168: 115194-115194
被引量:59
标识
DOI:10.1016/j.watres.2019.115194
摘要
The UV/persulfate (PS) process is a promising water treatment technology, and it can not only effectively degrade contaminants of emerging concern, but also control formation of disinfection byproducts (DBPs). In this study, we investigated the potential and mechanisms of chloropicrin (i.e. trichloronitromethane, TCNM) formation during chlorination that followed UV/PS pretreatment in the presence of low concentrations of nitrite. We found that when nitrite was present in the UV/PS system, unexpected high concentrations of TCNM were formed. The formation potential of TCNM was impacted by operational conditions and water matrix components: (1) high pH enhanced TCNM formation; (2) high UV fluence inhibited TCNM formation; and (3) organic compounds containing phenolic groups enhanced TCNM formation. We discovered that electrophilic substitutions by reactive nitrogen species were favored for phenolic groups, and thus more nitrite-N was transformed to organic nitrogen. We also found that more TCNM was generated from natural organic matter than algal organic matter during chlorination following pretreatment using UV/PS. Accordingly, more attention needs to be paid to TCNM formation, if nitrite is present and the water is pretreated using UV/PS (when applied at upstream of chlorination). For example, we found that if monochloramine was used as a disinfectant downstream of the UV/PS process, the formation of TCNM was reduced.
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