SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Han Chen,Tao Lin,Xiaoshu Yan,Hang Xu
The formation of haloacetonitriles (HANs) during chlorination after sulfite/ultraviolet (UV) treatment of bromate (BrO 3 − ) in the presence of amino acids (AAs) was investigated. During sulfite/UV treatment, the primary species hydrated electrons (e aq − ) and hydrogen atom radicals (H ) dominated the reduction of BrO 3 − to bromide (Br − ), whereas the sulfite anion radicals (SO 3 − ) and H degraded AAs to produce the intermediates HN=C(CH 3 )–COOH, CH 3 –CH=NH, and CH 3 –C≡N via α‑hydrogen abstraction and NH 2 –hydrogen abstraction mechanisms. During post-chlorination, Br − was converted to HBrO/BrO-, and the HN=C(CH 3 )–COOH, CH 3 –CH=NH, and CH 3 –C≡N groups featured higher bromine utilization factor (BUF) and chlorine utilization factor (CUF) values than AAs, enhancing the formation of dibromoacetonitrile (DBAN) and dichloroacetonitrile (DCAN). The energetic feasibility of the transformation pathway, that is, HN=C(CH 3 )–COOH, CH 3 –CH=NH, and CH 3 –C ≡ N formation via hydrogen abstraction by SO 3 − and H and their further conversion to HANs, was proved by density functional theory calculations, which showed stepwise negative Gibbs free energy changes (ΔG < 0). The effects of pH and water matrices (e.g., HCO 3 − , Cl − , Fe 3+ , and natural organic matter) were comprehensively evaluated. Although 72% of BrO 3 − was removed by sulfite/UV treatment in the presence of AAs, the cytotoxicity index (CTI) and genotoxicity index (GTI) during post-chlorination increased by 213% and 125%, respectively, due to the formation of 24 CX 3 R-type disinfection by-products (DBPs), especially brominated DBPs. Accordingly, more attention should be given to the formation of brominated DBPs during post-chlorination when using sulfite/UV processes to remove BrO 3 − in the presence of AAs. As a solution, using monochloramine instead of chlorine as a disinfectant after the sulfite/UV process could significantly lower the CTI and GTI values by alleviating the formation of brominated DBPs.
研究领域:
环境科学
·
水处理
·
化学工程
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Ziying Wang,Yisheng Shao,Naiyun Gao,Bin Xu,Na An,Xian Lu
Applying the highly oxidative sulfate radical ( SO 4 - · ) to pollutant degradation may cause it to react with the coexisting bromide (Br − ) to form undesired byproducts. This study investigated the transformation of Br − during the degradation process of a contaminant (diethyl phthalate (DEP)) via heat-activated persulfate (PS). Dibromoacetonitrile and bromoform formed with Br − and natural organic matter (NOM) in the solution, while only bromoform was detected without NOM. The formation of these brominated disinfection byproducts (Br-DBPs) can be ascribed to the reactions between the phenolic groups of DEP degradation intermediates or NOM and reactive bromine species (free bromine and radical bromine) generated through the oxidation of Br − by SO 4 - · . Br-DBPs were degraded by excessive SO 4 - · , which indicates that organic bromine is a temporary phase during the turnover of Br − . The time-dependent formation of organic and inorganic bromines suggests that Br − may have cycled several times between organic and inorganic forms before eventually turning into bromate. The bromate formation showed a lag phase before continuously increasing. Generally, increasing the temperature, PS dosage, and Br − and organic matter (DEP and NOM) concentrations increased the maximum concentration of Br-DBPs. Additionally, these reaction parameters facilitated bromate formation except for organic matter, whose inhibitory effect is probably due to the consumption of reactive species by organic matter and the generated superoxide anion. The total organic carbon concentration of the solution exhibited a relatively quick reduction followed by a slow decrease. These results highlight the potential risks of PS activation technologies and can help prevent such risks in actual practice.
研究领域:
环境科学
·
水处理
·
化学工程
·
污染物降解
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Qian-Yuan Wu,Lu-Lin Yang,Xin-Yang Zhang,Wen-Long Wang,Yao Lu,Ye Du,Yun Lu,Hong-Ying Hu
Ammonia (NH4+) and hydrogen peroxide (H2O2) have been widely used to inhibit bromate formation during ozonation. However, organic byproducts can also pose a risk under these conditions. During bromate inhibition, the influence of NH4+ and H2O2 on organic byproducts and their toxicity should be elucidated. Our study found that NH4+ suppressed organic bromine, but might result in increased toxicity. Adding 0.5 mg/L of NH4+–N substantially increased both the formation of cytotoxicity and genotoxicity (DNA double-strand breaks) of organic byproducts from 0.6 to 1.6 mg-phenol/L, and from 0.3 to 0.8 μg-4-NQO/L (0.5 mg/L Br–, 5 mg/L O3). NH4+ decreased bromate, but increased the overall toxicity of the integrated byproducts (organic byproducts and bromate). Organic nitrogen measurements and 15N isotope analysis showed enhanced incorporation of nitrogen into organic matter when NH4+ and Br– coexisted during ozonation. NH4+ decreased the formation of brominated acetonitriles, but enhanced the formation of brominated nitromethanes and brominated acetamides. These brominated nitrogenous byproducts were partially responsible for this increase in toxicity. Different from ammonia, H2O2 could reduce both bromate and the toxicity of organic byproducts. In the presence of 0.5 mg/L Br– and 10 mg/L O3, adding H2O2 (0.5 mM) substantially suppressed bromate, cytotoxicity formation and genotoxicity formation by 88%, 63% and 67%. This study highlights that focusing on bromate control with NH4+ addition might result in higher toxicity. Efforts are needed to effectively control the toxicities of bromate and organic byproducts simultaneously.
研究领域:
环境科学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENT INTERNATIONAL
·
2019
·
IF 7.943
Feilong Dong,Jiaqi Liu,Cong Li,Qiufeng Lin,Tuqiao Zhang,Kejia Zhang,Virender K. Sharma
Algal organic matter (AOM) from seasonal algal blooms may be an important precursor of disinfection byproducts (DBPs) in drinking water. This paper presents the effect of ferrate(VI) treatment on two blue-green algae, Chlorella sp. and Pseudanabaena limnetica , in eutrophic water. The results demonstrated that Fe(VI) removed the algal cells by causing cell death, apoptosis, and lost integrity, and decreased AOM (in terms of total organic carbon) in water via oxidation and coagulation. Chlorination of the Fe(VI) pre-oxidized algal water samples generated halogenated DBPs (including trihalomethanes, haloacetic acids, haloketones, chloral hydrate, haloacetonitriles, and trichloronitromethane), but the concentrations of DBPs were lower than those formed in the chlorinated samples without pre-treatment by Fe(VI). Higher Fe(VI) dose, longer oxidation time, and alkaline pH were beneficial in controlling DBPs. In bromide-containing algal solutions, negligible amount of bromo-DBPs were generated in the Fe(VI) pre-oxidation, and halogenated DBPs were mainly formed in the subsequent chlorination.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Zhen Pang,Peifeng Zhang,Xinyi Chen,Feilong Dong,Jing Deng,Cong Li,Junping Liu,Xiaoyan Ma,Andrea M. Dietrich
Disinfection byproducts (DBPs) are initially formed in the process of chlorination in the drinking water treatment plants (DWTPs), then further formed in the distribution system due to the presence of residual chlorine and reactive organic matters. However, in China, DBPs are monitored in the effluent from the DWTPs, but less is known about concentrations of DBPs in tap water since they are usually monitored once per half a year. The smart water service system is establishing real-time monitoring of water indices, although DBPs are an urgent need, they are difficult to monitor in real-time due to their diversity and complicated detection methods. If the correlation between DBP concentration and routinely real-time monitored water quality parameters (e.g., pH value, residual chlorine, ammonia) can be evaluated, the concentration of DBPs can be predicted, which will strengthen the control of tap water safety. This article comprehensively assessed the physicochemical parameters and the occurrence of DBP formation in the tap water with an 18-month investigation in Z city (China). DBP formation in tap water of different seasons and different water sources were compared. Based on the relationship between DBPs and physicochemical parameters, linear prediction and nonlinear prediction models of trihalomethanes (THMs), haloacetonitriles (HANs) and haloacetic acids (HAAs) were established, and the accuracy of these models was verified by measured data. Finally, the toxicity and carcinogenic and non-carcinogenic health risk assessment of DBPs in tap water were analyzed.
研究领域:
环境科学
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公共卫生
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Feilong Dong,Zhen Pang,Jianquan Yu,Jing Deng,Xueyan Li,Xiaoyan Ma,Andrea M. Dietrich,Yang Deng
Distributions of halogenated disinfection byproducts (DBPs) in a two-source water distribution system (WDS) with enhanced chlorination were investigated. The WDS was divided into different sub-service areas based on different electrical conductivity of two water sources. Results clearly show that the principal halogenated DBPs were trihalomethanes (THMs) (5.06–82.69 μg/L), varying within the concentration range as 2–5 times as the levels of haloacetic acids (HAAs) (1.41–61.48 μg/L) and haloacetonitriles (HANs) (0.21–15.13 μg/L). Different water sources, treatment trains, and enhanced chlorination within the WDS had significant effects on seasonal and spatial variations of the DBP distributions over water conveyance. THM and HAA formation followed the sequence of summer > autumn > winter > spring. On the other hand, the DBP spatial distributions were visualized using the ArcGIS enabled Inverse distance weighting technique. The superposition of different DBP spatial distributions allowed for the identification of the high-risk THMs and HAAs areas based on the average values of THMs (27.49 μg/L) and HAAs (14.06 μg/L). Beyond the comprehensive analyses of DBP distribution in a municipal WDS , the project proposed and validated an innovative methodology to locate the DBP high-risk areas and to reveal the effects of different factors on DBPs distribution in a two-source WDS.
研究领域:
环境科学
·
公共卫生
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYST
·
2023
·Vol. 148
·期 21
·5390-5394
·
IF 4.2
Jiaben Zhong,Hangyan Zhang,Yina Cai,Xiuping Chen,Zhiyuan Fang,Dun Deng
Dichloroacetonitrile (DCAN) is a common biotoxic disinfection by-product (DBP) of chlorine. The current methods used for detecting DCAN are tedious and heavily instrument-dependent, and are not suitable for on-site detection. In the present study, we developed a colorimetric assay for rapid detection of DCAN. DCAN in water acted as a complexing agent that formed a complex with cuprous species. The cuprous species was then extracted by chloroform and visualized using dithizone. The visual detection limit for DCAN was 20 ng mL−1, while fluorescence quantification could detect DCAN at a concentration as low as 8.75 ng mL−1. Moreover, haloacetonitriles (HANs) derived from chlorine disinfection and structurally similar to DCAN, including TCAN, BCAN, and DBAN, could also be detected using this method. Other DBPs at concentrations as high as 200 ng mL−1 did not affect the detection process. The low cost and instrument-independence characteristic of the present method enables its routine determination of the concentration of DCAN in water.
研究领域:
环境科学
·
分析化学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）