SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Jing Liu,Jing Wang,Jie Zhang,Yang Mu
In this study, the impact of Cu 2+ on the formation of iodo-trihalomethanes (I-THMs) during chlorination and chloramination of iodide-containing waters was investigated. Initially, the oxidant consumption and evolution of hypoiodous acid (HOI) were determined during disinfection in the presence of Cu 2+ and the interaction between natural organic matter humic acid (HA) and Cu 2+ was also analyzed. Subsequently, the formation of the I-THMs at various Cu 2+ concentrations was evaluated for chlorination and chloramination. Moreover, in order to explore the possible underlying mechanisms, five model compounds based on the HA structure were used to investigate the I-THMs formation with and without Cu 2+ during disinfection. The results indicated that the presence of Cu 2+ markedly affected the conformation of the HA rather than the HOI evolution during disinfection. The concentration of the I-THMs decreased from 34.5 ± 0.8 to 20.9 ± 0.8 nM as the Cu 2+ concentration increased from 0 to 20 μM during chlorination. In contrast, during chloramination, the total I-THMs concentration decreased from 320.7 ± 7.4 to 267.2 ± 10.7 nM as the Cu 2+ concentration increased from 0 to 5 μM and then increased to 315.0 ± 1.7 nM when the Cu 2+ concentration reached 20 μM. The disinfection experiments with the model compounds suggested that the impact of Cu 2+ on the I-THMs formation largely depended on the organic structures in the HA, thus leading to different results during chlorination and chloramination.
研究领域:
环境科学
·
水处理工程
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DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Shuang Zhang,Yi-Li Lin,Tian-Yang Zhang,Chen-Yan Hu,Zhi Liu,Zheng-Yu Dong,Meng-Yuan Xu,Bin Xu
In this study, the formation of iodinated trihalomethanes (I-THMs) was systematically evaluated and compared for three treatment processes - (i) chlorination, (ii) monochloramine, and (iii) dichloramination - under different pH conditions. The results demonstrated that I-THM formation decreased in the order of monochloramination > dichloramination > chlorination in acidic and neutral pH. However, the generation of I-THMs increased in the dichloramination < chlorination < monochloramination order in alkaline condition. Specifically, the formation of I-THMs increased as pH increased from 5 to 9 during chlorination and monochloramination processes, while the maximum I-THM formation occurred at pH 7 during dichloramination. The discrepancy could be mainly related to the stability of the three chlor (am) ine disinfectants at different pH conditions. Moreover, in order to gain a thorough insight into the mechanisms of I-THM formation during dichloramination, further investigation was conducted on the influencing factors of DOC concentration and Br − /I − molar ratio. I-THM formation exhibited an increasing and then decreasing trend as the concentration of DOC increased from 1 to 7 mg-C/L, while the yield of I-THMs increased with increasing Br − /I − molar ratio from 5:0 to 5:10. During the three processes mentioned above, similar I-THM formation results were also obtained in real water, which indicates that the excessive generation of I-THMs should be paid special attention during the disinfection of iodide-containing water.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Cong Li,Qiufeng Lin,Feilong Dong,Yuanhao Li,Feng Luo,Kejia Zhang
Chlorination is essential to provide safe drinking water . However, this process leads to the formation of disinfection byproducts (DBPs). In this study, tryptophan (Trp) has been selected as a precursor to conduct the chlorine disinfection. Moreover, the factors that affect the formation of trihalomethanes (THMs) and iodinated trihalomethanes (I-THMs) are investigated. The formation pathway of Trp chlorination is proposed based on the intermediate products identified. According to the experimental results, the formation of THMs and I-THMs during Trp chlorination fitted a new first-order kinetic model. The dosage of chlorine, temperature, pH and the ratio of bromide and iodide had major influence on the formation of THMs and I-THMs during chlorination. In addition, the inhibition of luminescent bacteria Vibrio fischeri in the water sample increased during Trp chlorination.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2022
·
IF 13.4
Jing Wang,Jie Zhang,Jing Liu,Nannan Hou,Qi Li,Guannan Zhou,Kewan Li,Yang Mu
Copper water pipelines are widely used in water distribution systems, but the effects of solid copper corrosion products (CCPs) including CuO, Cu 2 O and Cu 2 (OH) 2 CO 3 on the generation of iodinated trihalomethanes (I-THMs) during chloramination remain unknown. This study found that the formation of I-THMs during chloramination of humic acid (HA) was inhibited by the presence of CuO and Cu 2 O, but promoted with the addition of Cu 2 (OH) 2 CO 3 . The negative effect of CuO and Cu 2 O is mainly exerted by promoting the decay of both NH 2 Cl and HOI. Although Cu 2 (OH) 2 CO 3 also accelerated the decomposition of NH 2 Cl and HOI, it was found that the complexes formed between Cu 2 (OH) 2 CO 3 and HA facilitated, through carboxyl functional groups, the reaction between HA and HOI, leading to an enhancement of I-THM generation during chloramination, which was further confirmed by model compound experiments. Additionally, this study demonstrated that the effects of solid CCPs on I-THM generation during chloramination were solid CCP- and HA-concentration dependent, but almost unaffected by different initial I − and Br − concentrations. This study provides new insights into the health risks caused by the corrosion of copper water pipelines, especially in areas intruded by sea water.
研究领域:
环境科学
·
公共卫生
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Pengwei Yan,Zhonglin Chen,Shuyu Wang,Yanchi Zhou,Jimin Shen,Shengxin Zhao,Lei Yuan,Weiqiang Wang,Xiaotong Xu,Xinwei Zhu,Jing Kang
The formation of iodinated by-products during the chemical oxidation process for organic compounds contaminated water has gained increasing attention. Iodinated by-products are more genotoxic, cytotoxic and mutagenic than those of chlorine and bromine analogs. It was reported that the oxidation process of iodinated X-ray contrast media (ICM) could generate iodinated by-products. This study investigated the generation of iodinated by-products during catalytic ozonation of iohexol (one of wide detected ICM). The formation of iodoform (IF) and monoiodoacetic acid (MIAA), and the degradation kinetics of iohexol were compared in different oxidation systems. The effect of various factors, including the iohexol concentration, ozone concentration, HA concentration and solution pH on iodinated by-products generation was evaluated. Additionally, the fate of iodine was investigated by the mass balance calculation. The generated concentrations of I-THMs species with one iodide atom were far higher than those of species with more iodine atoms in the catalytic system at the coexistence of Cl − and Br − . The generation of I-THMs in actual water was relatively low and the normalized value of I-THMs/DOC (μg/mg) had no significant difference. The formation mechanism of high molecular weight iodine-containing by-products included cleavage of the side chain, H-abstraction, substitution iodine for chlorine or bromine and amide oxidation.
研究领域:
环境科学
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毒理学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2015
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IF 4.321
Zhen Wang,Yi-Li Lin,Bin Xu,Sheng-Ji Xia,Tian-Yang Zhang,Nai-Yun Gao
Degradation kinetics of iohexol by UV/chlorine advanced oxidation process (AOP) and the formation of iodinated trihalomethanes (I-THMs) during post-chlorination were investigated in this study. Iohexol, a commonly detected iodinated contrast media in water, can be effectively removed during UV/chlorine process with pseudo-first-order reaction kinetics due to the combination of UV photolysis and oxidation of hydroxyl radicals . The second-order rate constant between iohexol and hydroxyl radicals was determined as 3.8 × 10 9 M −1 s −1 by competition kinetic experiment. Five intermediates were identified by ultra performance liquid chromatography–electrospray ionization-mass spectrometry analysis and degradation pathways of iohexol during UV/chlorine were proposed. Effects of chlorine dose, pH and bromide concentration on iohexol degradation and I-THM formation during post-chlorination were also studied. The results showed that iohexol degradation was accelerated with the increase of chlorine concentration as well as the decrease of pH and bromide concentration. On the other hand, I-THM formation from post-chlorination of UV/chlorine treated iohexol favored relatively low chlorine doses, high bromide concentrations at circumneutral conditions. Raw water experiments showed that I-THM formation after post-chlorination of UV/chlorine-treated iohexol was lower compared to that from UV irradiation, indicating that UV/chlorine is superior to UV alone in controlling I-THM formation.
研究领域:
环境科学
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水处理工程
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化学动力学
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产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2023
·Vol. 39
·期 3
·449-454
·
IF 3.1
Wang Junyao,Hu Xialin,Liu Meichuan,Yin Daqiang
Iodinated trihalomethanes(I-THMs) in drinking water pipelines have attracted wide attention due to their high toxicity. The coexistence of widely present lead dioxide(PbO 2 ) with commonly used disinfectant sodium hypochlorite(NaClO) in drinking water might change the formation characteristics of I-THMs due to the strongly oxidizing properties of PbO 2 . This study investigated the formation of I-THMs during the co-oxidation of natural organic matter including humic acid(HA), extracellular organic matter(EOM), and intracellular organic matter(IOM) of algogenic organic matter by PbO 2 and NaClO. Triiodomethane(CHI 3 ) is the dominant product in the single oxidation system of PbO 2 , whereas trichloromethane (CHCl 3 ), chlorodiiodomethane(CHClI 2 ), and dichloroiodomethane (CHCl 2 I) are the major products in the single NaClO system. In the co-oxidation system, the dominant I-THMs are similar to those in the single NaClO system. However, the CHCl 3 content decreased to 56.4% whereas I-THMs concentrations remained unchanged with the increase of PbO 2 concentration. The main reason is attributed to the reduced residual chlorine content due to the reaction of PbO 2 with NaClO. IOM is more prone to forming I-THMs than HA and EOM due to the specified structures. This study suggested that PbO 2 in the drinking water supply pipelines might change the risk of THMs.
研究领域:
环境科学
·
饮用水安全
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）