Effects of Sunlight on the Formation Potential of Dichloroacetonitrile and Bromochloroacetonitrile from Wastewater Effluents
Effects of Sunlight on the Formation Potential of Dichloroacetonitrile and Bromochloroacetonitrile from Wastewater Effluents
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阳光对废水中二氯乙腈和溴氯乙腈形成潜力的影响
DOI：
10.1021/acs.est.9b06526
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发表时间：
2020
影响因子：
11.4
通讯作者：
Dai, Ning
中科院分区：
文献类型：
--
作者：
Xu, Jiale;Kralles, Zachary T.;Hart, Christine H.;Dai, Ning
阳光在废水向下游流动时转化废水中的有机物方面起着重要作用，但对受废水影响的地表水中卤代乙腈（HAN）（一组有毒消毒副产物）形成的相应影响尚未得到彻底研究。在这项研究中，我们观察到，阳光优先衰减溴氯乙腈（BCAN-FP）的形成电位超过二氯乙腈（DCAN-FP）在氯和紫外线消毒二级流出物。对于来自不同工厂的四个废水样品，模拟阳光照射36小时，去除28-33%的DCAN-FP和41-48%的BCAN-FP。在一组较大的流出物样品（n= 18），8小时的照射（相当于2-3天的自然阳光）减少了计算的细胞毒性贡献的二卤乙腈-FP在大多数样品。对于废水和地表水的混合物（体积比1：1）观察到类似的行为。对于UV消毒的流出物，UV剂量越高，在随后的阳光照射中DCAN-FP和BCAN-FP的减少越可能。模型化合物的实验表明，富里酸和色氨酸的UV光产物在太阳光照射下产生激发的三重态有机物，并在促进HAN前体的衰减中起重要作用。
Sunlight plays an important role in transforming effluent organic matter as wastewater effluents travel downstream, but the corresponding effects on the formation of haloacetonitriles (HANs), a group of toxic disinfection byproducts, in wastewater-impacted surface water have not been thoroughly investigated. In this study, we observed that sunlight preferentially attenuated the formation potential of bromochloroacetonitrile (BCAN-FP) over that of dichloroacetonitrile (DCAN-FP) in chlorine- and UV-disinfected secondary effluents. For four effluent samples from different plants, 36 h of irradiation by simulated sunlight removed 28–33% of DCAN-FP and 41–48% of BCAN-FP. Across a larger set of effluent samples (n= 18), 8 h of irradiation (equivalent to 2–3 d of natural sunlight) decreased the calculated cytotoxicity contributed by dihaloacetonitrile-FP in most samples. Similar behavior was observed for a mixture of wastewater and surface water (volume ratio 1:1). For UV-disinfected effluents, the higher the UV dose, the more likely was there a reduction in DCAN-FP and BCAN-FP in the subsequent sunlight irradiation. Experiments with model compounds showed that fulvic acid and UV photoproducts of tryptophan yield excited triplet-state organic matters during sunlight irradiation and play an important role in promoting the attenuation of HAN precursors.