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Zhong Y, Chen Y, Ong SL, Hu J, Balakrishnan V, Ang WS. Disinfection by-products control in wastewater effluents treated with ozone and biological activated carbon followed by UV/Chlor(am)ine processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:171317. [PMID: 38428610 DOI: 10.1016/j.scitotenv.2024.171317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/03/2024]
Abstract
Sequential utilization of ozone (O3) and biological activated carbon (BAC) followed by UV/chlor(am)ine advanced oxidation process (AOP) has drawn attention in water reuse. However, the formation of disinfection by-products (DBPs) in this process is less evaluated. This study investigated the DBP formation and the relevant toxicity during the O3-BAC-UV/chlor(am)ine treatment of sand-filtered municipal secondary effluent. DBP formation in UV/chlorine and UV/dichloramine (NHCl2) processes were compared, where the impact of key operational parameters (e.g., UV wavelength, pH) on DBP formation were comprehensively evaluated. O3-BAC significantly reduced DBP formation potential (DBPFP) (58.2 %). Compared to UV/chlorine AOP, UV/NHCl2 AOP reduced DBP formation by 29.7 % in short-time treatment, while insignificantly impacting on DBPFP (p > 0.05). UV/NHCl2 AOP also led to lower calculated cytotoxicity (67.7 %) and genotoxicity (55.9 %) of DBPs compared to UV/chlorine AOP. Compared to 254 nm UV light, the utilization of 285 nm UV light decreased the formation of DBPs in wastewater treated with the UV/chlorine AOP and UV/NHCl2 AOP by 31.3 % and 19.2 %, respectively. However, the cytotoxicity and genotoxicity in UV/NHCl2 AOP using 285 nm UV light increased by 83.4 % and 58.5 %, respectively, compared to 254 nm. The concentration of DBPs formed in the UV/NHCl2 AOP at pH 8 was 54.3 % lower than that at pH 7, suggesting a better control of DBPs at alkaline condition. In the presence of bromide, UV/NHCl2 AOP tended to generate more brominated DBPs than UV/chlorine AOP. Overall, UV/NHCl2 AOP resulted in lower concentration and toxicity of DBPs compared to UV/chlorine AOP.
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Affiliation(s)
- Yu Zhong
- Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore
| | - Yiwei Chen
- Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore
| | - Say Leong Ong
- Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore
| | - Jiangyong Hu
- Department of Civil & Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
| | - Viswanath Balakrishnan
- Water Reclamation (Plants) Department, PUB Singapore, 40 Scotts Road, Environment Building, Singapore 228231, Singapore
| | - Wui Seng Ang
- Water Reclamation (Plants) Department, PUB Singapore, 40 Scotts Road, Environment Building, Singapore 228231, Singapore
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Zhou Y, Jiao JJ, Huang H, Liu YD, Zhong R, Yang X. Insights into C-C Bond Cleavage Mechanisms in Dichloroacetonitrile Formation during Chlorination of Long-Chain Primary Amines, Amino Acids, and Dipeptides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18834-18845. [PMID: 37183372 DOI: 10.1021/acs.est.2c07779] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Dichloroacetonitrile (DCAN) as one of the potentially prioritized regulated DBPs has drawn great attention; however, understanding its formation, especially the C-C bond cleavage mechanisms, is limited. In this study, DCAN formation mechanisms from long-chain primary amines, amino acids, and dipeptides during chlorination were investigated by a combined computational and experimental approach. The results indicate that nitriles initially generate for all of the above precursors, then they undergo β-C-hydroxylation or/and α-C-chlorination processes, and finally, DCAN is produced through the Cα-Cβ bond cleavage. For the first time, the underlying mechanism of the C-C bond cleavage was unraveled to be electron transfer from the O- anion into its attached C atom in the chlorinated nitriles, leading to the strongly polarized Cα-Cβ bond heterocleavage and DCAN- formation. Moreover, DCAN molar yields of precursors studied in the present work were found to be determined by their groups at the γ-site of the amino group, where the carbonyl group including -CO2-, -COR, and -CONHR, the aromatic group, and the -OH group can all dramatically facilitate DCAN formation by skipping over or promoting the time-consuming β-C-hydroxylation process and featuring relatively lower activation free energies in the C-C bond cleavage. Importantly, 4-amino-2-hydroxybutyric acid was revealed to possess the highest DCAN yield among all the known aliphatic long-chain precursors to date during chlorination. Additionally, enonitriles, (chloro-)isocyanates, and nitriles can be generated during DCAN formation and should be of concern due to their high toxicities.
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Affiliation(s)
- Yingying Zhou
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Jia-Jia Jiao
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Huang Huang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yong Dong Liu
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China
| | - Xin Yang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
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Sheng D, Bu L, Zhu S, Wu Y, Wang J, Li N, Zhou S. Impact of pre-oxidation on the formation of byproducts in algae-laden water disinfection: Insights from fluorescent and molecular weight. J Environ Sci (China) 2022; 117:21-27. [PMID: 35725073 DOI: 10.1016/j.jes.2021.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/02/2021] [Accepted: 12/26/2021] [Indexed: 06/15/2023]
Abstract
Pre-oxidation has been reported to be an effective way to remove algal cells in water, but the released algal organic matter (AOM) could be oxidized and lead to the increment in disinfection by-product (DBP) formation. The relationship between pre-oxidation and AOM-derived DBP formation needs to be approached more precisely. This study compared the impact of four pre-oxidants, ozone (O3), chlorine dioxide (ClO2), potassium permanganate (KMnO4) and sodium hypochlorite (NaClO), on the formation of nitrogenous (N-) and carbonaceous (C-) DBPs in AOM chlorination. The characterization (fluorescent properties, molecular weight distribution and amino acids concentration) on AOM samples showed that the characterization properties variations after pre-oxidation were highly dependent on the oxidizing ability of oxidants. The disinfection experiments showed that O3 increased DBP formation most significantly, which was consistent with the result of characterization properties variations. Then canonical correspondent analysis (CCA) and Pearson's correlation analysis were conducted based on the characterization data and DBP formation. CCA indicated that C-DBPs formation was highly dependent on fluorescent data. The formation of haloacetic acids (HAAs) had a positive correlation with aromatic protein-like component while trichloromethane (TCM) had a positive correlation with fulvic acid-like component. Pearson's correlation analysis showed that low molecular weight fractions were favorable to form N-DBPs. Therefore, characterization data could provide the advantages in the control of DBP formation, which further revealed that KMnO4 and ClO2 were better options for removing algal cells as well as limiting DBP formation.
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Affiliation(s)
- Da Sheng
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Lingjun Bu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Shumin Zhu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Yangtao Wu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Jue Wang
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Nan Li
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Shiqing Zhou
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha 410082, China.
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Zhou Y, Ye ZX, Huang H, Liu YD, Zhong R. Formation mechanism of chloropicrin from amines and free amino acids during chlorination: A combined computational and experimental study. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125819. [PMID: 33865110 DOI: 10.1016/j.jhazmat.2021.125819] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 03/22/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
Chloropicrin as one of the most frequently detected N-DBPs has drawn great attention due to its high toxicity. However, our understanding of its formation mechanism is still very limited. A combined computational and experimental approach was used in this study to reveal chloropicrin formation mechanism during chlorination. Ethylamine, n-propylamine, alanine and tryptophan along with the above two amines and their four derivatives substituted by -OH or/and -NO2 groups were chosen as computational and experimental model precursors, respectively. The results indicate that primary amines and free amino acids are more likely to share the same chloropicrin formation pathway including N-chlorination, imidization, β-C-alcoholization, N-nitration, α-C-chlorination and dealdehydation processes. Moreover, elimination of hydrochloric acid from N,N-dichloro-amine and electrophilic addition of N-chloroalkylimide with hypochlorous acid were found to be the rate-limiting steps among all the elementary reactions. By skipping over both of the above rate-limiting steps, RCH(OH)CH2NO2 and RCH(OH)CH2NH(OH) compounds were proposed to be potent chloropicrin precursors, and experiments confirmed that 2-nitroethanol and N-methylhydroxylamine have the highest chloropicrin yields in the chlorination among all the precursors reported to date. The findings of this work are helpful for expanding the knowledge of chloropicrin formation mechanisms and predicting the potential chloropicrin precursors.
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Affiliation(s)
- Yingying Zhou
- Beijing Key Laboratory of Environmental and Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Zhao-Xi Ye
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Huang Huang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Yong Dong Liu
- Beijing Key Laboratory of Environmental and Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental and Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China
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Tsamba L, Cimetière N, Wolbert D, Correc O, Le Cloirec P. Body fluid analog chlorination: Application to the determination of disinfection byproduct formation kinetics in swimming pool water. J Environ Sci (China) 2020; 87:112-122. [PMID: 31791485 DOI: 10.1016/j.jes.2019.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Disinfection by-products (DBPs) are formed in swimming pools by the reactions of bather inputs with the disinfectant. Although a wide range of molecules has been identified within DBPs, only few kinetic rates have been reported. This study investigates the kinetics of chlorine consumption, chloroform formation and dichloroacetonitrile formation caused by human releases. Since the flux and main components of human inputs have been determined and formalized through Body Fluid Analogs (BFAs), it is possible to model the DBPs formation kinetics by studying a limited number of precursor molecules. For each parameter the individual contributions of BFA components have been quantified and kinetic rates have been determined, based on reaction mechanisms proposed in the literature. With a molar consumption of 4 mol Cl2/mol, urea is confirmed as the major chlorine consumer in the BFA because of its high concentration in human releases. The higher reactivity of ammonia is however highlighted. Citric acid is responsible for most of the chloroform produced during BFA chlorination. Chloroform formation is relatively slow with a limiting rate constant determined at 5.50 × 10-3 L/mol/sec. L-histidine is the only precursor for dichloroacetonitrile in the BFA. This DBP is rapidly formed and its degradation by hydrolysis and by reaction with hypochlorite shortens its lifetime in the basin. Reaction rates of dichloroacetonitrile formation by L-histidine chlorination have been established based on the latest chlorination mechanisms proposed. Moreover, this study shows that the reactivity toward chlorine differs whether L-histidine is isolated or mixed with BFA components.
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Affiliation(s)
- Lucie Tsamba
- Rennes University, ENSCR, CNRS, ISCR - UMR 6226, F - 35000 Rennes, France; Scientific and Technical Center for Buildings, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France.
| | - Nicolas Cimetière
- Rennes University, ENSCR, CNRS, ISCR - UMR 6226, F - 35000 Rennes, France
| | - Dominique Wolbert
- Rennes University, ENSCR, CNRS, ISCR - UMR 6226, F - 35000 Rennes, France
| | - Olivier Correc
- Scientific and Technical Center for Buildings, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France
| | - Pierre Le Cloirec
- Rennes University, ENSCR, CNRS, ISCR - UMR 6226, F - 35000 Rennes, France
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