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Chuang YH, Chen TY, Chou CS, Chu LK, Hou CY, Szczuka A. Critical Role of Trichloramine Interaction with Dichloramine for N-Nitrosamine Formation during Breakpoint Chlorination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15232-15242. [PMID: 37603422 DOI: 10.1021/acs.est.3c03326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Breakpoint chlorination is prevalent in drinking water and potable reuse water treatment. Breakpoint chlorination enhances the formation of N-nitrosamines through reactions that form nitrosating agents. The most recent study suggests that nitroxyl (HNO) can react with free chlorine (HOCl) to form the nitrosyl chloride (ClNO) nitrosating agent but has not experimentally verified its importance in breakpoint chlorination. This study first assessed the formation of N-nitrosamines from model N-chloro-alkylamine precursors when they were added to a mixture of HOCl and HNO-derived nitrosating agents generated by chlorinating hydroxyurea. Results demonstrated negligible N-nitrosamine formation. Instead, we observed that the interaction of NCl3 with NHCl2 (total Cl2/total N molar ratio = 2.4-3:1) produced an intermediate capable of nitrosating N-chloro-alkylamines to N-nitrosamines at yields 8-fold higher to those observed in NHCl2 treatment alone, within a very short timescale (<3 min). We examined the stoichiometry of the reaction of NCl3 with NHCl2 using a UV-spectrum-based approach. Nitrosyl chloride was proposed as the key intermediate, likely formed alongside the reformation of NHCl2. Further isotopic experiments, byproduct measurements, and kinetic modeling supported the hypotheses. Modeling indicated that the reaction of NCl3 with NHCl2 explained ∼75% of NDMA formation during breakpoint chlorination. Because NCl3 is mainly derived from the reaction of HOCl with NHCl2, controlling NHCl2 (e.g., with additional treatment) is critical for minimizing nitrosamine formation in waters where breakpoint chlorination occurs.
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Affiliation(s)
- Yi-Hsueh Chuang
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Ting-Yuan Chen
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Chia-Shun Chou
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Li-Kang Chu
- Department of Chemistry, National Tsing Hua University, 101, Sec 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Chun-Yao Hou
- Department of Chemistry, National Tsing Hua University, 101, Sec 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Aleksandra Szczuka
- Department of Civil and Environmental Engineering, University of Michigan, 1351 Beal Ave. Ann Arbor, Michigan 48109, United States
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Szczuka A, Huang N, MacDonald JA, Nayak A, Zhang Z, Mitch WA. N-Nitrosodimethylamine Formation during UV/Hydrogen Peroxide and UV/Chlorine Advanced Oxidation Process Treatment Following Reverse Osmosis for Potable Reuse. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15465-15475. [PMID: 33185421 DOI: 10.1021/acs.est.0c05704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Chloramines applied to control microfiltration and reverse osmosis (RO) membrane biofouling in potable reuse trains form the potent carcinogen, N-nitrosodimethylamine (NDMA). In addition to degrading other contaminants, UV-based advanced oxidation processes (AOPs) strive to degrade NDMA by direct photolysis. The UV/chlorine AOP is gaining attention because of its potential to degrade other contaminants at lower UV fluence than the UV/hydrogen peroxide AOP, although previous pilot studies have observed that the UV/chlorine AOP was less effective for NDMA control. Using dimethylamine (DMA) as a model precursor and secondary municipal wastewater effluent, this study evaluated NDMA formation during the AOP treatment via two pathways. First, NDMA formation by UV treatment of monochloramine (NH2Cl) and chlorinated DMA (Cl-DMA) passing through RO membranes was maximized at 350 mJ/cm2 UV fluence, declining at higher fluence, where NDMA photolysis outweighed NDMA formation. Second, this study demonstrated that chlorine addition to the chloramine-containing RO permeate during the UV/chlorine AOP treatment initiated rapid NDMA formation by dark breakpoint reactions associated with reactive intermediates from the hydrolysis of dichloramine. At pH 5.7, this formation was maximized at a chlorine/ammonia molar ratio of 3 (out of 0-10), conditions typical for UV/chlorine AOPs. At 700 mJ/cm2 UV fluence, which is applicable to current practice, NDMA photolysis degraded a portion of the NDMA formed by breakpoint reactions. Lowering UV fluence to ∼350 mJ/cm2 when switching to the UV/chlorine AOP exacerbates effluent NDMA concentrations because of concurrent NDMA formation via the UV/NH2Cl/Cl-DMA and breakpoint chlorination pathways. Fluence >700 mJ/cm2 or chlorine doses greater than the 3:1 chlorine/ammonia molar ratios under consideration for the UV/HOCl AOP treatment are needed to achieve NDMA control.
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Affiliation(s)
- Aleksandra Szczuka
- Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305United States
| | - Nan Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jessica A MacDonald
- Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305United States
| | - Adam Nayak
- Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305United States
| | - Zhong Zhang
- Institute of Environmental & Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - William A Mitch
- Department of Civil and Environmental Engineering, Stanford University, 473 Via Ortega, Stanford, California 94305, United States
- National Science Foundation Engineering Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California 94305United States
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Zhang R, Meng T, Huang CH, Ben W, Yao H, Liu R, Sun P. PPCP Degradation by Chlorine-UV Processes in Ammoniacal Water: New Reaction Insights, Kinetic Modeling, and DBP Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7833-7841. [PMID: 29906121 DOI: 10.1021/acs.est.8b00094] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The combination of chlorine and UV (i.e., chlorine-UV process) has been attracting more attention in recent years due to its ready incorporation into existing water treatment facilities to remove PPCPs. However, limited information is available on the impact of total ammonia nitrogen (TAN). This study investigated two model PPCPs, N,N-diethyl-3-toluamide (DEET) and caffeine (CAF), in the two stages of the chlorine-UV process (i.e., chlorination and UV/chlor(am)ine) to elucidate the impact of TAN. During chlorination, the degradation of DEET and CAF was positively correlated with the overall consumption of total chlorine by TAN. Reactive nitrogen intermediates, including HNO/NO- and ONOOH/ONOO-, along with •OH were identified as major contributors to the removal of DEET and CAF. During UV irradiation, DEET and CAF were degraded under UV/chlorine or UV/NH2Cl conditions. •OH and •Cl were the major reactive species to degrade DEET and CAF under UV/NH2Cl conditions, whereas •OCl played a major role for degrading CAF under UV/chlorine conditions. Numerical models were developed to predict the removal of DEET and CAF under chlorination-UV process. Chlorinated disinfection byproducts were detected. Overall, this study presented kinetic features and mechanistic insights on the degradation of PPCPs under the chlorine-UV process in ammoniacal water.
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Affiliation(s)
- Ruochun Zhang
- Xiamen Urban Water Environmental Eco-Planning and Remediation Engineering Research Center (XMERC) , Xiamen 361021 , China
| | | | - Ching-Hua Huang
- School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Weiwei Ben
- Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Hong Yao
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
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Wang WL, Wu QY, Du Y, Huang N, Hu HY. Elimination of chlorine-refractory carbamazepine by breakpoint chlorination: Reactive species and oxidation byproducts. WATER RESEARCH 2018; 129:115-122. [PMID: 29145081 DOI: 10.1016/j.watres.2017.11.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/27/2017] [Accepted: 11/05/2017] [Indexed: 06/07/2023]
Abstract
Breakpoint chlorination can be commonly observed in the chlorination of water treatments when ammonia is present. In this study, it was found that breakpoint chlorination can remarkably eliminate a ubiquitous and chlorine-refractory micropollutant, carbamazepine (CBZ), with the removal of 72% at neutral condition. At neutral pH, low CBZ elimination was observed at a chlorine/ammonia molar ratio (Cl/N) of 1.0 and higher CBZ elimination was observed as Cl/N ratio increased from 1.0 to 1.6 (breakpoint), indicating that CBZ elimination was closely related to the generation and decomposition of chloramines. The chloramines generation and decomposition rates were affected by the pH, so that the CBZ elimination rate was highest at pH 7.0 and lower in acidic and basic solutions (pH 5.5 and pH 9.5, respectively). The CBZ elimination at pH 7.0 was 72.4% after 10 min of breakpoint chlorination, while reaction times about 30 min and 60 min were required to achieve the same elimination at pH 5.5 and pH 9.5, respectively. Breakpoint chlorination of CBZ was strongly suppressed by radical scavenger tBuOH and moderately suppressed by N2 purging, the inhibiting ratios being 87.7% and 27.8% at breakpoint, respectively. Electron spin resonance experiments suggested that unidentified radicals were generated by breakpoint chlorination. The OH and unidentified radical species contributions to CBZ elimination were <23.7% and >76.3%, respectively, when a pseudo steady state breakpoint chlorination was performed in a microinjection system with nitrobenzene as OH probe. Although CBZ were efficiently eliminated, breakpoint chlorination of CBZ generated adsorbable organic chlorine. The cytotoxicity of the CBZ solution was therefore increased by breakpoint chlorination, suggesting that biological risk caused by the breakpoint chlorination of micropollutants should be taken into consideration.
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Affiliation(s)
- Wen-Long Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Qian-Yuan Wu
- Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China.
| | - Ye Du
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Nan Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China.
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Soltermann F, Lee M, Canonica S, von Gunten U. Enhanced N-nitrosamine formation in pool water by UV irradiation of chlorinated secondary amines in the presence of monochloramine. WATER RESEARCH 2013; 47:79-90. [PMID: 23098367 DOI: 10.1016/j.watres.2012.09.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/13/2012] [Accepted: 09/17/2012] [Indexed: 06/01/2023]
Abstract
N-Nitrosamines, in particular N-nitrosodimethylamine (NDMA), are carcinogens, which occur as chlorine disinfection by-products (DBPs) in swimming pools and hot tubs. UV treatment is a commonly used technique in swimming pools for disinfection and DBP attenuation. UV irradiation is known to efficiently degrade N-nitrosamines. However, UV irradiation (at λ = 254 nm) of chlorinated dimethylamine (CDMA) and monochloramine, two NDMA precursors present in swimming pool water, resulted in a substantial UV-induced NDMA formation (~1-2% molar yield based on initial CDMA concentration) simultaneously to NDMA photolysis. Maximum NDMA concentrations were found at UV doses in the range used for advanced oxidation (350-850 mJ cm(-2)). Very similar behaviour was found for other chlorinated secondary amines, namely diethylamine and morpholine. Effectiveness of UV irradiation for N-nitrosamine abatement depends on initial N-nitrosamine and precursor concentrations and the applied UV dose. N-Nitrosamine formation is hypothesized to occur via the reaction of nitric oxide or peroxynitrite with the secondary aminyl radical, which are products from the photolysis of monochloramine and chlorinated secondary amines, respectively. Experiments with pool water showed that similar trends were observed under pool water conditions. UV treatment (UV dose: ~360 mJ cm(-2)) slightly increased NDMA concentration in pool water instead of the anticipated 50% abatement in the absence of NDMA precursors.
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Affiliation(s)
- Fabian Soltermann
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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Sun Z, Liu YD, Zhong RG. Reactions of amine and peroxynitrite: evidence for hydroxylation as predominant reaction and new insight into the modulation of CO2. J Phys Chem A 2012; 116:8058-66. [PMID: 22770388 DOI: 10.1021/jp304290r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Peroxynitrite is related to numerous diseases including cardiovascular diseases, inflammation, and cancer. In order to expand the understanding for the toxicology of peroxynitrite in biological system, the reactions of amine (morpholine as a probe) with peroxynitrite and the modulation of CO2 were investigated by using DFT methods. The results strongly indicate that the hydroxylation of amine by peroxynitrous acid ONOOH, which was previously overlooked by most studies, is predominant relative to the widely reported nitration and nitrosation in the absence of CO2. The product N-hydroxylamine is proposed to be mainly generated via nonradical pathway (two-electron oxidation). The modulation of CO2 exhibits two main functions: (1) inhibition of hydroxylation due to the promoted consumption of peroxynitrite via fast reaction of CO2 with ONOO¯ to form ONOOCO2¯; (2) dual effect (catalysis and inhibition) of CO2 toward nitration and nitrosation. As a new insight, amine does react with CO2 and produce inert amine carbamate R2NCOO¯. This reaction has the potential to compete with the reaction of CO2 and ONOO¯, which leads to inhibition of nitration and nitrosation. The concentration of CO2 could be a critical factor determining the final effect, catalysis or inhibition. As a new finding, HCO3¯ is probably an effective catalyst for the reaction of amine and CO2. Moreover, further studies on how the different types of the amine might affect the outcome of the reactions would be an interesting topic.
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Affiliation(s)
- Zhi Sun
- College of Life Science & Bioengineering, Beijing University of Technology , Beijing 100124, P. R. China
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Abstract
Melatonin is easily nitrosated via various mechanisms at the nitrogen atom of the indole ring to give N-nitrosomelatonin (NOMela). This mini-review provides a comprehensive view of this N-nitroso compound. With an improved procedure NOMela can now economically synthesized with low laboratory expenditure. The major chemical property of NOMela, i.e. the (formally) transfer of the NO+ function to its target nucleophile, is explained in detail and a variety of detection methods using this reaction are suggested. As the suspected carcinogenical potential of NOMela is clearly overruled it seems attractive to apply this nitroso compound for endogenous generation of S-nitrosothiols that act as nitric oxide donors in vivo.
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Affiliation(s)
- Michael Kirsch
- Institut für Physiologische Chemie, Universitätsklinikum Essen, Essen, Germany.
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Walse SS, Mitch WA. Nitrosamine carcinogens also swim in chlorinated pools. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:1032-7. [PMID: 18351068 DOI: 10.1021/es702301p] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Highly carcinogenic N-nitrosodialkylamine (nitrosamine) disinfection byproducts were quantified in chlorinated swimming pools, hot tubs, and aquaria. N-Nitrosodimethylamine, the most abundant nitrosamine detected, was measured in swimming pools and hot tubs at levels up to 500-fold greater than the drinking water concentration of 0.7 ng/L associated with a one in one million lifetime cancer risk. Temperature, enclosure, amine and nitrite precursor loading, and the use of disinfection schemes with reduced chlorine doses contributed to statistically significant variability in its occurrence. N-Nitrosodibutylamine and N-nitrosopiperidine were also detected but together represented <5% of the total analyte distribution. The presence of N-nitrodimethylamine at levels comparable to N-nitrosodimethylamine points to a competition between the nitration and nitrosation of amines in chlorinated recreational waters. Since nitrosamines can cause bladder cancer, the significance of our measurements needs clarification with respect to recent epidemiological results that are suggestive of a link between swimming in chlorinated pools and bladder cancer.
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Affiliation(s)
- Spencer S Walse
- Department of Chemical Engineering, Mason Laboratory 313b, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
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Kirsch M, Korth HG. Generation, basic chemistry, and detection of N-nitrosotryptophan derivatives. Org Biomol Chem 2007; 5:3889-94. [PMID: 18043791 DOI: 10.1039/b713377b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N-Terminal blocked tryptophan derivatives like melatonin or tryptophan residues in peptides are easily nitrosated at the nitrogen atom of the indole ring to give the corresponding N-nitrosotryptophan derivatives. This article provides a comprehensive view of the synthesis, chemical properties, and detection methods of this class of N-nitroso compounds of potential importance in biological systems.
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Affiliation(s)
- Michael Kirsch
- Institut für Physiologische Chemie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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Schreiber IM, Mitch WA. Enhanced nitrogenous disinfection byproduct formation near the breakpoint: implications for nitrification control. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:7039-7046. [PMID: 17993145 DOI: 10.1021/es070500t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Increasing the chlorine to ammonia molar ratio and breakpoint chlorination are two control strategies practiced by drinking water treatment utilities experiencing nitrification during chloramination. The first strategy will increase dichloramine formation, which increases nitrosamine formation. Moreover, our results indicate that dichloramine is also an important factor for nitrile formation. Near the breakpoint, nitrosamine formation is over an order of magnitude higher than that observed during chloramination. We propose that there are two nitrosamine formation pathways active in the breakpoint chlorination region: (i) a relatively slow reaction of dichloramine with amine precursors in the presence of dissolved oxygen and (ii) a fast reaction involving reactive breakpoint chlorination intermediates. Lastly, in the presence of nitrite, if breakpoint chlorination is conducted to achieve a significant free chlorine residual, nitrosamines and nitramines will form through a reaction with nitrite and hypochlorite. However, nitrosamine formation will be much lower than when breakpoint chlorination is conducted with no significant free chlorine residual.
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Affiliation(s)
- I Marie Schreiber
- Department of Chemical Engineering, Yale University, Mason Lab 313b, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
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