JOURNAL OF HAZARDOUS MATERIALS
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2025
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IF 11.3
Yan Shen,Xinyi Weng,Jingsi Chen,Jiafu Li
The aldehyde addition reaction is recognized as a key pathway in the formation of haloacetamides (HAMs) in drinking water. In particular, the reaction between monochloramine and chloroaldehydes has been reported to proceed rapidly. However, the measured concentrations of haloaldehydes (HALs) in chloraminated water are often much higher than those of HAMs. This discrepancy suggests that the role of the aldehyde pathway in HAM formation may have been overestimated. In this study, two commonly detected HALs [dichloroacetaldehyde (DCAL) and trichloroacetaldehyde (TCAL)] were selected as model compounds to investigate the transformation and formation among three classes of toxic disinfection byproducts (DBPs): HALs, HAMs, and haloacetonitriles (HANs), within a chloramination system. Theoretical calculations reveal that HALs can form HAMs via two distinct reaction pathways. Quantum-level computational analyses confirm the thermodynamic feasibility of both pathways for the studied Cl-HALs. Experimental investigations of the reaction kinetics between Cl-HALs and monochloramine, conducted at room temperature under light-shielded and catalyst-free conditions, showed that the concentrations of both DCAL and TCAL remained essentially unchanged throughout the reaction. HANs and HAMs in reaction solution were not detected. These results suggest that HALs exhibit negligible reactivity with monochloramine under ambient, uncatalyzed conditions, indicating strong kinetic hindrance in practical scenarios. In general, the reaction rate between HALs and monochloramine is not as high as that reported in the published literature (3.27–8.25 ×10 −3 h −1 ), which may help explain why much higher concentrations of HALs than HAMs were generally observed in chloraminated drinking water. This finding provides new insights into the transformation and formation of HALs, HAMs, and HANs in chloraminated drinking water systems.
研究领域:
环境化学
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水处理
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毒理学
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化学反应工程
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
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2024
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IF 7.6
Fangyuan Peng,Yingyang Wang,Yi Lu,Zhaoguang Yang,Haipu Li
The increasing demand for trichloroisocyanuric acid (TCCA) in swimming pool disinfection highlights the need to evaluate its applicability in terms of disinfection by-product (DBP) formation. Nevertheless, there is limited understanding of DBP formation and control during TCCA disinfection, particularly concerning the effects of various management parameters. This study aimed to fill this knowledge gap by comprehensively investigating DBP formation during TCCA chlorination, with a particular focus on assessing the contribution and interaction of influencing factors using Box-Behnken Design and response surface methodology. Results indicated that the concentrations of trichloroacetaldehyde, chloroform, dichloroacetic acid, trichloroacetic acid, and dichloroacetonitrile produced by TCCA disinfectant were 42.5%, 74.0%, 48.1%, 94.7% and 42.6% of those by the conventional sodium hypochlorite disinfectant, respectively. Temperature exhibited the most significant impact on chloroform formation (49%), while pH played a major role in trichloroacetaldehyde formation (44%). pH 2 emerged as the primary contributor to dichloroacetic acid (90%) and trichloroacetic acid (93%) formation. The optimum water quality conditions were determined based on the minimum total DBPs (pH = 7.32, Temperature = 23.7 °C, [Cl − ] = 437 mg/L). Chlorine dosage and contact time exhibited greater influence than precursor concentration on chloroform, dichloroacetonitrile, trichloroacetaldehyde, trichloroacetic acid, and total DBPs. Although the interaction between water quality parameters was weak, the interaction between disinfection operating parameters demonstrated substantial effects on DBP formation (8.56–19.06%). Furthermore, the DBP predictive models during TCCA disinfection were provided for the first time, which provides valuable insights for DBP control and early warning programs.
研究领域:
环境科学
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水处理
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化学工程
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公共卫生
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Guangrong Sun,Han Yeong Kaw,Meijiao Zhou,Pei Guo,Lizhong Zhu,Wei Wang
Identification of emerging disinfection byproducts (DBPs) of health relevance is important to uncover the health risk of drinking water observed in epidemiology studies. In this study, mutagenic chlorinated nucleotides were proposed as potential DBPs in drinking water, and the formation and transformation pathways of these DBPs in chlorination of nucleotides were carefully investigated. A total of eleven chlorinated nucleotides and analogs were provisionally identified as potential DBPs, such as monochloro uridine/cytidine/adenosine acid and dichloro cytidine acid, and the formation mechanisms involved chlorination, decarbonization, hydrolysis, oxidation and decarboxylation . The active sites of nucleotides that reacted with chlorine were on the aromatic heterocyclic rings of nucleobases, and the carbon among the two nitrogen atoms in the nucleobases tended to be transformed into carboxyl group or be eliminated, further forming ring-opening or reorganization products. Approximately 0.2–4.0 % (mol/mol) of these chlorinated nucleotides and analogs finally decomposed to small-molecule aliphatic DBPs, primarily including haloacetic acids, trichloromethane, and trichloroacetaldehyde. Eight intermediates, particularly chlorinated imino- D -ribose and imino- D -ribose, were tentatively identified in chlorination of uridine. This study provides the first set of preliminary evidence for indicating the promising occurrence of chlorinated nucleotides and analogs as potential toxicological-relevant DBPs after disinfection of drinking water.
研究领域:
环境科学
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水处理
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毒理学
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化学
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产品关联
DOI
PubMed
高影响因子
ACS Earth and Space Chemistry
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2024
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IF 2.9
Cici Fan,Weigang Wang,Bo Shi,Zheng Sun,Maofa Ge
The relative rate method was used to determine the rate constant of Cl atoms and 3-buten-1-ol at ambient temperature and pressure. The main products of the reaction were identified as HCOOH with a yield of (50.07 ± 2.65)%, HCHO with a yield of (18.24 ± 0.65)%, HOCH2CHO with a yield of (18.69 ± 0.68)%, ClCH2CHO with a yield of (7.64 ± 0.25)%, respectively. The rate constant was (3.04 ± 0.36) × 10–10 cm3 molecules–1 s–1. The calculated theoretical rate constant was 2.91 × 10–10 cm3 molecules–1 s–1, which was in agreement with the experimental results. Moreover, the theoretical calculation showed that the two Cl-addition pathways were the main reaction pathway, but the proportion of H-abstraction pathways reached 29%, and its importance cannot be ignored. Based on this, the possible reaction mechanisms were deduced. The atmospheric implications of the obtained title reaction were briefly discussed.
研究领域:
大气化学
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物理化学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2025
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IF 7.2
Xiaoqin Li,Yuqi Su,Ronghai Bai,Qibin Li
Electrochemical oxidation (EO) effectively degrades phenolic compounds in phenol-containing wastewater, but the chlorinated byproducts generated during the process raised concerns. In this study, degradation efficiency of phenol and formation rules of chlorinated byproducts in the presence of chlorine (Cl − )were systematically and comparatively studied in two EO systems with boron-doped diamond (BDD) and ruthenium-iridium-coated titanium (RuO 2 -IrO 2 /Ti) as anodes. The results showed that Cl − significantly enhanced phenol degradation efficiency of the two anode systems. At the same Cl − concentration, degradation efficiency of BDD-EO was superior to that of RuO 2 -IrO 2 /Ti-EO, it had a higher apparent removal rate for phenolic compounds, including phenol, 4-NP, 4-CP, BPA, and RES, and was less affected by coexisting ions. However, in the BDD-EO system, the total amount of produced chlorinated byproducts (3.593 mM Cl) was approximately 50 times greater than that produced in the RuO 2 -IrO 2 /Ti-EO system (0.0723 mM Cl). These chlorinated byproducts included inorganic chloro-byproducts (ClO 3 − and ClO 4 − ) and organic chloro-byproducts (such as chloroform, trichloroacetic acid, and trichloroacetaldehyde). The results confirmed that HOCl generated by the oxidation of Cl − on BDD and RuO 2 -IrO 2 /Ti anodes through the • OH/direct electron transfer was the key active species for enhancing the phenol degradation and driving the formation of chlorinated byproducts. The toxicity assessment shows that the additive toxicity of inorganic chloro-byproducts in the RuO 2 -IrO 2 /Ti-EO system is approximately 1/57 that in the BDD-EO system, and the toxicity of organic chloro-byproducts is approximately 1/18. Selecting the appropriate anode is therefore critical to balance treatment efficiency with the need to minimize toxic chlorinated byproducts.
研究领域:
环境工程
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电化学
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水处理技术
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化学毒理学
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产品关联
DOI
高影响因子
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