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Xue Q, Deng L, Tang Q, Wang T, Luo W. Formation of halonitromethanes from benzylamine during UV/chlorination: Impact factors, toxicity alteration, and pathways. Environ Sci Pollut Res Int 2024; 31:16437-16452. [PMID: 38319423 DOI: 10.1007/s11356-024-32132-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/18/2024] [Indexed: 02/07/2024]
Abstract
Halonitromethanes (HNMs), a representative nitrogen-containing disinfection byproduct, have gained significant concerns due to their higher cytotoxicity and genotoxicity. UV/chlorination is considered a promising alternative disinfection technology for chlorination. This study aimed to investigate the HNMs formation from benzylamine (BZA) during UV/chlorination. The experimental results revealed that the yields of HNMs initially raised to a peak then dropped over time. Higher chlorine dosage and BZA concentration promoted the formation of HNMs, whereas alkaline pH inhibited their formation. The presence of bromine ion (Br-) not only converted chlorinated-HNMs (Cl-HNMs) to brominated (chlorinated)-HNMs Br (Cl)-HNMs) and brominated-HNMs (Br-HNMs) but also enhanced the total concentration of HNMs. Besides, the calculated cytotoxicity index (CTI) and genotoxicity index (GTI) of HNMs were elevated by 68.97% and 60.66% as Br- concentration raised from 2 to 6 µM. The possible formation pathways of HNMs from BZA were proposed based on the intermediates identified by a gas chromatography/mass spectrometry (GC/MS). In addition, the formation rules of HNMs in actual water verified the results in deionized water during UV/chlorination. The results of this study provide basic data and a theoretical basis for the formation and control of HNMs, which is conducive to applying UV/chlorination.
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Affiliation(s)
- Qi Xue
- Department of Municipal Engineering, Southeast University, Jiangning, Nanjing, Jiangsu, 211189, People's Republic of China
| | - Lin Deng
- Department of Municipal Engineering, Southeast University, Jiangning, Nanjing, Jiangsu, 211189, People's Republic of China.
| | - Qian Tang
- Department of Municipal Engineering, Southeast University, Jiangning, Nanjing, Jiangsu, 211189, People's Republic of China
| | - Tao Wang
- Department of Municipal Engineering, Southeast University, Jiangning, Nanjing, Jiangsu, 211189, People's Republic of China
| | - Wei Luo
- Department of Municipal Engineering, Southeast University, Jiangning, Nanjing, Jiangsu, 211189, People's Republic of China
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Tang Q, Zhu L, Wang Q, Deng L, Hu J, Singh RP. Formation of halonitromethanes from glycine during LED-UV 265/chlorine disinfection. J Environ Manage 2023; 348:119225. [PMID: 37832297 DOI: 10.1016/j.jenvman.2023.119225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/16/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023]
Abstract
LED-UV265/chlorine is a promising alternative disinfection technology that emits mono-wavelength light for high germicidal efficiency. Halonitromethanes (HNMs) are highly cytotoxic and genotoxic disinfection byproducts that can be formed during LED-UV265/chlorine disinfection. Thus, this work aimed to investigate the HNMs formation from glycine (Gly) during LED-UV265/chlorine disinfection. The results indicated that the concentrations of chlorinated-HNMs (Cl-HNMs) increased first and then decreased as the reaction proceeded. Besides, the effects of operating parameters (UV intensity, free chlorine dosage, and pH) and coexisting ions (Cu2+ and Br-) on HNMs formation were investigated. It was found that the formation concentrations of Cl-HNMs increased with the increase of LED-UV265 intensity and free chlorine dosage but decreased with increased pH. The presence of Cu2+ promoted the formation of Cl-HNMs. The total concentration of HNMs (at 3 min) with adding 1.5 mg/L Cu2+ was 30.90% higher than that without Cu2+. Notably, nine species of HNMs were detected after adding Br-, and the total concentrations of HNMs were enhanced. Moreover, Cl-HNMs were gradually transformed into brominated (chlorinated)-HNMs and brominated-HNMs as Br- concentration increased. According to the findings, the possible formation mechanism of HNMs from Gly during LED-UV265/chlorine disinfection was deduced. Finally, it was demonstrated that the formation laws of HNMs from Gly in real water samples were basically consistent with those in simulated water. Insights obtained in this study help to comprehend the HNMs formation from Gly and provide strategies for controlling the production of HNMs during LED-UV265/chlorine disinfection.
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Affiliation(s)
- Qian Tang
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China
| | - Liangwen Zhu
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China
| | - Qing Wang
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China
| | - Lin Deng
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China.
| | - Jun Hu
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China; College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Rajendra Prasad Singh
- Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, Nanjing 211189, China
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Wang T, Deng L, Shen J, Tan C, Hu J, Singh RP. Formation, toxicity, and mechanisms of halonitromethanes from poly(diallyl dimethyl ammonium chloride) during UV/monochloramine disinfection in the absence and presence of bromide ion. J Environ Manage 2023; 338:117819. [PMID: 36996559 DOI: 10.1016/j.jenvman.2023.117819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/22/2023] [Accepted: 03/25/2023] [Indexed: 06/19/2023]
Abstract
Bromide ion (Br-) is known as a prevalent component in water environments, which exhibits significant impacts on halonitromethanes (HNMs) formation. This study was performed to explore and compare the formation, toxicity, and mechanisms of HNMs from poly(diallyl dimethyl ammonium chloride) (PDDACl) in the absence and presence of Br- in the UV/monochloramine (UV/NH2Cl) disinfection process. The results showed that chlorinated HNMs were found in the absence of Br-, while brominated (chlorinated) HNMs and brominated HNMs were found in the presence of Br-. Furthermore, the peaks of total HNMs were promoted by 2.0 and 2.4 times, respectively when 1.0 and 2.0 mg L-1 Br- were added. Also, the peaks of total HNMs were enhanced with the increase of the NH2Cl dosage, which were reduced with the increase of pH. It should be noted that Br- induced higher toxicity of HNMs, and the cytotoxicity and genotoxicity of HNMs with the addition of 2.0 mg L-1 Br- were 78.0 and 3.7 times those without the addition of Br-, respectively. Meanwhile, both the reaction mechanisms of HNMs produced from PDDACl were speculated in the absence and presence of Br-. Finally, different HNMs species and yields were discovered in these two real water samples compared to those in simulated waters. These findings of this work will be conducive to understanding the significance of Br- affecting HNMs formation and toxicity in the disinfection process.
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Affiliation(s)
- Tao Wang
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Lin Deng
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China.
| | - Jiaxin Shen
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Chaoqun Tan
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Jun Hu
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
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Xu B, Deng L, Zhang S, Luo W, Hu J, Tan C, Singh RP. Analysis of degradation kinetic modeling and mechanism of chlorinated-halonitromethanes under UV/monochloramine treatment. Environ Pollut 2023; 319:120972. [PMID: 36584856 DOI: 10.1016/j.envpol.2022.120972] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/17/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
Chlorinated-halonitromethanes (Cl-HNMs) including chloronitromethane (CNM), dichloronitromethane (DCNM), and trichloronitromethane (TCNM) are nitrogenous disinfection by-products, which have high cytotoxicity and genotoxicity to human. This study aimed to investigate the degradation kinetic modeling and mechanism of Cl-HNMs under monochloramine activated by ultraviolet of 254 nm (UV/NH2Cl) treatment. The first-principle kinetic model of UV/NH2Cl process was developed to simulate Cl-HNMs degradation. Of note, the second-order rate constants of Cl-HNMs reacting with HO• (∼108 M-1 s-1), Cl• (kCl•,CNM or DCNM = ∼1010 M-1 s-1, kCl•,TCNM = ∼102 M-1 s-1), Cl2•- (kCl•,CNM or DCNM = ∼109 M-1 s-1, kCl•,TCNM = ∼101 M-1 s-1), ClO• (∼105-106 M-1 s-1) and CO3•- (∼106-107 M-1 s-1) were obtained by the first-principle kinetic model. Overall, Cl-HNMs degradation under UV/NH2Cl treatment was successfully predicted by the kinetic model under various conditions. It was found that UV (>60%) was dominant in Cl-HNMs degradation, followed by HO• (3.8%-24.5%), reactive chlorine species (RCS, 0.9%-28.8%) and CO3•- (0-26.1%). Among the contributions of RCS, Cl• and Cl2•- were main radicals in the degradation of CNM and DCNM, while ClO• was responsible for the abatement of TCNM. The minimum EE/O values under UV/NH2Cl treatment were approximately 30% lower than those under UV treatment. Finally, the possible degradation pathways were proposed, including hemolytic/heterolytic cleavage of Cl-HNMs by UV irradiation, hydrogen abstraction/electron transfer of CNM and DCNM and adduct reaction of TCNM by free radicals. This study based on the kinetic model is beneficial to predict and control the concentrations of Cl-HNMs under UV/NH2Cl treatment.
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Affiliation(s)
- Bohui Xu
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Lin Deng
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China.
| | - Shizheng Zhang
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Wei Luo
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
| | - Jun Hu
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China; College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Chaoqun Tan
- Department of Municipal Engineering, Southeast University, Nanjing, 211189, China
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Deng L, Huang T, Wen L, Hu J, Prasad Singh R, Tan C. Impact of bromide ion on the formation and transformation of halonitromethanes from poly(diallyldimethylammonium chloride) during the UV/chlorine treatment. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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