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Huang S, Liu H, Wei K, Zhang L, Ma X, Li Q, Li X, Dietrich AM. Impact of ozonation on disinfection byproducts formation from phenylalanine during chlorination. J Environ Sci (China) 2024; 144:199-211. [PMID: 38802231 DOI: 10.1016/j.jes.2023.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 05/29/2024]
Abstract
As a strong oxidizing agent, ozone is used in some water treatment facilities for disinfection, taste and odor control, and removal of organic micropollutants. Phenylalanine (Phe) was used as the target amino acid to comprehensively investigate variability of disinfection byproducts (DBPs) formation during chlorine disinfection and residual chlorine conditions subsequent to ozonation. The results showed that subsequent to ozonation, the typical regulated and unregulated DBPs formation potential (DBPsFP), including trichloromethane (TCM), dichloroacetonitrile (DCAN), chloral hydrate (CH), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and trichloroacetamide (TCAcAm) increased substantially, by 2.4, 3.3, 5.6, 1.2, 2.5, and 6.0 times, respectively, compared with only chlorination. Ozonation also significantly increased the DBPs yield under a 2 day simulated residual chlorine condition that mimicked the water distribution system. DBPs formations followed pseudo first order kinetics. The formation rates of DBPs in the first 6 hr were higher for TCM (0.214 hr-1), DCAN (0.244 hr-1), CH (0.105 hr-1), TCAcAm (0.234 hr-1), DCAA (0.375 hr-1) and TCAA (0.190 hr-1) than thereafter. The peak DBPsFP of TCM, DCAN, CH, TCAcAm, DCAA, and TCAA were obtained when that ozonation time was set at 5-15 min. Ozonation times > 30 min increased the mineralization of Phe and decreased the formation of DBPs upon chlorination. Increasing bromine ion (Br-) concentration increased production of bromine- DBPs and decreased chlorine-DBPs formation by 59.3%-92.2% . Higher ozone dosages and slight alkaline favored to reduce DBP formation and cytotoxicity. The ozonation conditions should be optimized for all application purposes including DBPs reduction.
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Affiliation(s)
- Sinong Huang
- College of Civil Engineering, Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Zhejiang University of Technology, Hangzhou 310023, China
| | - Hongwei Liu
- College of Civil Engineering, Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Zhejiang University of Technology, Hangzhou 310023, China
| | - Kunming Wei
- College of Civil Engineering, Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Zhejiang University of Technology, Hangzhou 310023, China
| | - Liang Zhang
- College of Civil Engineering, Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Zhejiang University of Technology, Hangzhou 310023, China
| | - Xiaoyan Ma
- College of Civil Engineering, Zhejiang Key Laboratory of Civil Engineering Structures & Disaster Prevention and Mitigation Technology, Zhejiang University of Technology, Hangzhou 310023, China.
| | - Qingsong Li
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China
| | - Xueyan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Andrea M Dietrich
- Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blackburg, VA 24061, USA
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2
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Chen Z, Chen B, Shen H, Li X, Zhou C, Ma G, Wei X, Wang X, Yu H. Chlorination of Aromatic Amino Acids: Elucidating Disinfection Byproducts, Reaction Kinetics, and Influence Factors. Molecules 2024; 29:1879. [PMID: 38675699 PMCID: PMC11055117 DOI: 10.3390/molecules29081879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/11/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
In the face of ongoing water pollution challenges, the intricate interplay between dissolved organic matter and disinfectants like chlorine gives rise to potentially harmful disinfection byproducts (DBPs) during water treatment. The exploration of DBP formation originating from amino acids (AA) is a critical focus of global research. Aromatic DBPs, in particular, have garnered considerable attention due to their markedly higher toxicity compared to their aliphatic counterparts. This work seeks to advance the understanding of DBP formation by investigating chlorination disinfection and kinetics using tyrosine (Tyr), phenylalanine (Phe), and tryptophan (Trp) as precursors. Via rigorous experiments, a total of 15 distinct DBPs with accurate molecular structures were successfully identified. The chlorination of all three AAs yielded highly toxic chlorophenylacetonitriles (CPANs), and the disinfectant dosage and pH value of the reaction system potentially influence chlorination kinetics. Notably, Phe exhibited the highest degradation rate compared to Tyr and Trp, at both the CAA:CHOCl ratio of within 1:2 and a wide pH range (6.0 to 9.0). Additionally, a neutral pH environment triggered the maximal reaction rates of the three AAs, while an acidic condition may reduce their reactivity. Overall, this study aims to augment the DBP database and foster a deeper comprehension of the DBP formation and relevant kinetics underlying the chlorination of aromatic AAs.
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Affiliation(s)
| | | | | | | | | | - Guangcai Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua 321004, China; (Z.C.); (B.C.); (H.S.); (X.L.); (C.Z.); (X.W.); (X.W.)
| | | | | | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua 321004, China; (Z.C.); (B.C.); (H.S.); (X.L.); (C.Z.); (X.W.); (X.W.)
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3
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He H, Sun N, Li L, Zhou H, Hu A, Yang X, Ai J, Jiao R, Yang X, Wang D, Zhang W. Photochemical Transformation of Dissolved Organic Matter in Surface Water Augmented the Formation of Disinfection Byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38329881 DOI: 10.1021/acs.est.3c08155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Sunlight may lead to changes in disinfection byproducts (DBPs) formation potentials of source water via transforming dissolved organic matter (DOM); however, the underlying mechanisms behind these changes remain unclear. This work systematically investigated the effect of photochemical transformation of DOM from reservoir water (DOMRe) and micropolluted river water (DOMRi) after 36 h of simulated sunlight irradiation (equivalent to one month under natural sunlight) on DBPs formation. Upon irradiation, high molecular weight (MW) and aromatic molecules tended to be mineralized or converted into low-MW and highly oxidized (O/C > 0.5) ones which might react with chlorine to generate high levels of DBPs, resulting in an elevation in the yields (μg DBP/mg C) of almost all the measured DBPs and the quantities of unknown DBPs in both DOM samples after chlorination. Additionally, DOMRi contained more aromatic molecules susceptible to photooxidation than DOMRe. Consequently, irradiated DOMRi exhibited a greater increase in the formation potentials of haloacetonitriles, halonitromethanes, and specific regulated DBPs, with nitrogenous DBPs being responsible for the overall rise in the calculated cytotoxicity following chlorination. This work emphasized the importance of a comprehensive removal of phototransformation products that may serve as DBPs precursors from source waters, especially from micropolluted source waters.
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Affiliation(s)
- Hang He
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Niannian Sun
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Lanfeng Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Hao Zhou
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Aibin Hu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Xiaoyin Yang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Jing Ai
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ruyuan Jiao
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaofang Yang
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dongsheng Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Craven C, Wawryk NJP, Carroll K, James W, Shu Z, Charrois JW, Hrudey SE, Li XF. Amino Acids as Potential Precursors to Odorous Compounds in Tap Water during Spring Runoff Events. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18765-18774. [PMID: 37549310 PMCID: PMC10690712 DOI: 10.1021/acs.est.3c00719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 08/09/2023]
Abstract
The onset of spring runoff in northern climates and tap water odor events are difficult to predict because common water quality parameters cannot fully explain the intermittent odor events that occurred over past decades. Studies have shown that small polar water-soluble compounds, such as amino acids (AAs), leach first from ice/snowmelt. AAs are known to produce odorous compounds, such as aldehydes and chloroaldimines, upon chlorination. Therefore, we proposed that AAs may serve as markers for small and soluble organics that contribute to the odor of chlorinated tap water. Here, we studied the occurrence of AAs in source water collected at two water treatment plants and the odor profiles of tap water at >300 homes during the 2021 and 2022 spring runoff events. AA concentrations were at baseline levels (<100 ng/L) during the 2021 runoff but much higher (up to 5500 ng/L) in 2022 and associated with an escalation in odor complaints. AA concentrations peaked at the onset of the 2022 spring runoff and corresponded with the strongest reported odor intensities in tap water. We obtained high resolution MS and MS/MS spectra of chloroaldimines and confirmed the formation of chloroaldimines under chlorination of the six AAs detected in source water. The results indicate that AAs signal the onset of spring runoff and represent small polar water-soluble compounds that may contribute to tap water odor problems.
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Affiliation(s)
- Caley
B. Craven
- Division
of Analytical and Environmental Toxicology, Department of Laboratory
Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
| | - Nicholas J. P. Wawryk
- Division
of Analytical and Environmental Toxicology, Department of Laboratory
Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
| | - Kristin Carroll
- Division
of Analytical and Environmental Toxicology, Department of Laboratory
Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
| | - Wendell James
- EPCOR
Water Services Inc., 2000-10423 101 Street NWEdmonton, Alberta, Canada T5H 0E8
| | - Zengquan Shu
- EPCOR
Water Services Inc., 2000-10423 101 Street NWEdmonton, Alberta, Canada T5H 0E8
| | - Jeffrey W.A. Charrois
- EPCOR
Water Services Inc., 2000-10423 101 Street NWEdmonton, Alberta, Canada T5H 0E8
| | - Steve E. Hrudey
- Division
of Analytical and Environmental Toxicology, Department of Laboratory
Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
| | - Xing-Fang Li
- Division
of Analytical and Environmental Toxicology, Department of Laboratory
Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2G3
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Lou J, Yin L, Meng Z, Fang S, Pan X. Occurrence, stability and cytotoxicity of halobenzamides: A new group of nitrogenous disinfection byproducts in drinking water. WATER RESEARCH 2023; 245:120670. [PMID: 37778081 DOI: 10.1016/j.watres.2023.120670] [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: 07/02/2023] [Revised: 09/09/2023] [Accepted: 09/24/2023] [Indexed: 10/03/2023]
Abstract
Exploring disinfection byproducts (DBPs) with adverse health effects in drinking water is a constant challenge. Halobenzamides (HBZAMs) are suspected to be a new group of nitrogenous DBPs but have not been reported in drinking water to date. In this study, by coupling SPE and UPLC‒MS/MS, a sensitive method was established to detect eight HBZAMs in drinking water with recoveries and limits of detection of 80-103% and 0.01-0.04 ng/L, respectively. Subsequently, distinct fragments of HBZAMs were extended to the development of a pseudotargeted method for the analysis of the fourteen HBZAMs that were speculated and lack chemical standards. Using the developed method, eight HBZAMs were quantified in ten drinking water samples with concentrations ranging from 2.4 to 7.2 ng/L and a detection frequency of 100%, among which five HBZAMs were stable with half-lives over 72 h under real chlorine levels. Twelve HBZAMs without standards were identified in three to ten drinking water samples with comparable levels. The cytotoxicity of eight quantified HBZAMs in CHO-K1 cells varied with disparity, in which the cytotoxicity of 3,5-DBBZAM was over 10-fold higher than that of aliphatic dichloroacetamide. Considering their diversity, toxicity and stability, the occurrence of HBZAMs in drinking water deserves attention.
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Affiliation(s)
- Jinxiu Lou
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; Zhejiang Carbon Neutral Innovation Institute, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Lu Yin
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Zhu Meng
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Shuangxi Fang
- Zhejiang Carbon Neutral Innovation Institute, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Xiangliang Pan
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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6
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He H, Sun N, Li L, Ai J, Zhou H, Yang X, Yang X, Wang D, Zhang W. Effects of dissolved organic matter removal and molecular transformation in different water treatment processes on formation of disinfection byproducts. WATER RESEARCH 2023; 245:120626. [PMID: 37713793 DOI: 10.1016/j.watres.2023.120626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/16/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Alterations in molecular composition of dissolved organic matter (DOM) during water treatments can influence the composition and toxicity of disinfection by-products (DBPs) in subsequent chlorination disinfection process. In this study, the impacts of DOM composition after various water treatment techniques (coagulation, adsorption, nanofiltration, biological aerated filter (BAF), and their integrated processes) on the generation mechanisms of DBPs were comprehensively explored by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in combination with GC-MS and LC-MS analysis. The results indicated that coagulation preferentially removed unsaturated (low H/C) and oxidized (high O/C) compounds, whereas adsorption was prone to remove the reduced (low O/C) component that was more reactive with chlorine, leading to lower yields (μg DBP/mg DOC) of trihalomethanes (THMs) and haloacetic acids (HAAs) during subsequent chlorination. The coagulation-adsorption technique exhibited a relatively high removal of both known and unknown DBPs, demonstrating that coagulation and adsorption were complementary for DOM removal at the molecular level. Nanofiltration selectively removed molecules with relatively high O/C, however, those with very low O/C that were more reactive with chlorine could pass through the nanofiltration membrane, resulting in the highest yields of THMs and HAAs. Although BAF was inefficient in removing DBPs precursors, it could convert molecules with low degree of oxidation and unsaturation into highly oxidized and unsaturated ones, thereby significantly enhancing the removal of DBPs precursors in the subsequent coagulation-adsorption process. These findings are instrumental in developing and selecting more effective techniques to minimize the formation of DBPs in water treatment.
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Affiliation(s)
- Hang He
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Niannian Sun
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Lanfeng Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Jing Ai
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Hao Zhou
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Xiaoyin Yang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Xiaofang Yang
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dongsheng Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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7
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Sheng D, Bu L, Zhu S, Wu R, Shi Z, Zhou S. Pre-oxidation coupled with charged covalent organic framework membranes for highly efficient removal of organic chloramines precursors in algae-containing water treatment. CHEMOSPHERE 2023; 333:138982. [PMID: 37207898 DOI: 10.1016/j.chemosphere.2023.138982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 04/10/2023] [Accepted: 05/17/2023] [Indexed: 05/21/2023]
Abstract
Organic chloramines in water would pose both chemical and microbiological risks. It is essential to remove the precursors of organic chloramine (amino acids and decomposed peptides/proteins) to limit its formation in disinfection. In our work, nanofiltration was chosen to remove organic chloramines precursors. To solve the "trade-off" effect and low rejection of small molecules in algae organic matter, we synthesized a thin film composite (TFC) nanofiltration (NF) membrane with a crumpled polyamide (PA) layer via interfacial polymerization on polyacrylonitrile (PAN) composite support loaded with covalent organic framework (COF) nanoparticles (TpPa-SO3H). The obtained NF membrane (PA-TpPa-SO3H/PAN) increased the permeance from 10.2 to 28.2 L m-2 h-1 bar-1 and the amino acid rejection from 24% to 69% compared to the control NF membrane. The addition of TpPa-SO3H nanoparticles decreased the thickness of PA layers, increased the hydrophilicity of the membrane, and increased the transition energy barrier for amino acids transferring through the membrane, which was identified by scanning electron microscope, contact angle test, and density functional theory computations, respectively. Finally, pre-oxidation coupled with PA-TpPa-SO3H/PAN membrane nanofiltration on the limitation of organic chloramines formation was evaluated. We found that the combined application of KMnO4 pre-oxidation and PA-TpPa-SO3H/PAN membranes nanofiltration in algae-containing water treatment could minimize the formation of organic chloramines in subsequent chlorination and maintain a high flux during filtration. Our work provides an effective way for algae-containing water treatment and organic chloramines control.
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Affiliation(s)
- Da Sheng
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Lingjun Bu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Shumin Zhu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Ruoxi Wu
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Zhou Shi
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China
| | - Shiqing Zhou
- Hunan Engineering Research Center of Water Security Technology and Application, College of Civil Engineering, Hunan University, Changsha, 410082, PR China; Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha, 410082, PR China.
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Yang M, Zhang D, Chu W. Adsorption of highly toxic chlorophenylacetonitriles on typical microplastics in aqueous solutions: Kinetics, isotherm, impact factors and mechanism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 880:163261. [PMID: 37023804 DOI: 10.1016/j.scitotenv.2023.163261] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/04/2023] [Accepted: 03/31/2023] [Indexed: 04/14/2023]
Abstract
Microplastics (MPs) widely exist in all kinds of water bodies. The physical and chemical properties of MPs make them easy to become the carrier of pollutants, but the interaction between disinfection by-products (DBPs) and MPs has not been studied yet. In this study, the occurrence of emerging high-toxic chlorophenylacetonitriles (CPANs) in wastewater treatment plant (WWTP) effluents was determined. CPANs ubiquitously existed in WWTP effluents, and the concentration ranged from 88 ± 5 ng/L to 219 ± 16 ng/L. The typical MPs (i.e., polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS)) were selected to study their adsorption of CPANs. Adsorption kinetics and isotherm analysis were carried out. The maximum Langmuir adsorption capacities were 8.602 ± 0.849 to 9.833 ± 0.946 μg/g for PE, 13.340 ± 1.055 to 29.405 ± 5.233 μg/g for PET, and 20.537 ± 1.649 to 43.597 ± 1.871 for PS. Dichloro-CPANs had higher adsorption capacity than monochloro-CPANs. After that, the specific surface area, contact angle, FTIR spectrum, crystallinity, and glass transition temperature (Tg) of MPs were measured. Based on the analysis of the properties of both MPs and CPANs, the mechanism of adsorption was studied. The adsorption of CPANs on PE was mainly affected by pore-filling and van der Waals force. In addition to these two factors, the adsorption of PET was also affected by hydrophobic interaction. Due to the substituents on the benzene ring, there was π-π interaction between PS and CPANs, which might be the reason why PS had the highest adsorption capacity for CPANs. Finally, the effects of pH and dissolved organic matter were studied, and their effects were relatively limited. The results indicated that MPs may adsorb CPANs in actual WWTP effluents, and special attention should be paid to the possible impacts on the aquatic environment caused by the transfer of CPANs on MPs.
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Affiliation(s)
- Mansu Yang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Di Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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9
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Hong H, Lu Y, Zhu X, Wu Q, Jin L, Jin Z, Wei X, Ma G, Yu H. Cytotoxicity of nitrogenous disinfection byproducts: A combined experimental and computational study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159273. [PMID: 36209887 DOI: 10.1016/j.scitotenv.2022.159273] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/02/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
Nitrogenous disinfection byproducts (N-DBPs), such as halocetamides (HAcAms), haloacetonitriles (HANs) and halonitromethanes (HNMs), are emerging DBPs in drinking water. They are more toxic than currently regulated DBPs, attracting more attention to their toxic effects and mechanism. In this study, human embryonic kidney (HEK) 293T cells were employed to explore the cytotoxicity of 29 N-DBPs. The influence of molecular structures and different halogenations on cytotoxicity has been comparatively analyzed. As toxicity is the downstream of chemico-biological interactions, the thiol reactivity of 29 N-DBPs has thus been evaluated by using glutathione (GSH) as a model nucleophile, which is the most prevalent cellular thiol and acts as an antioxidant to protect cells by detoxifying electrophilic compounds. Results show that the cytotoxicity of N-DBPs follows by the order of HAcAms > HANs > HNMs, which is different from their reactivity with GSH (the median of kGSH ranks as HNMs > HAcAms > HANs). However, a significant correlation (p < 0.001) between log kGSH and log IC50 (concentration causing 50% inhibition) has been respectively observed for HAcAms and HANs subset and HNMs subset, indicating such chemical reaction is a probable trigger for these DBPs to result in cytotoxicity. Finally, two separate quantitative structure - activity relationship (QSAR) models based on HANs & HAcAms subset and HNMs subset have been developed for estimating IC50 values. The good statistical performance makes the models possible to quickly and accurately predict IC50 values of other N-DBPs, providing basic data for their health risk assessment and greatly reducing in vivo and in vitro experiments.
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Affiliation(s)
- Huachang Hong
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Yuchen Lu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Xiaoyan Zhu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Qiang Wu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Lingmin Jin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Zhigang Jin
- College of Chemistry and Life Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Xiaoxuan Wei
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Guangcai Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, 321004 Jinhua, China.
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10
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Ren Z, Qiu Y, Huan M, Liu YD, Zhong R. Identification of chlorinated products from tyrosine and tyrosyl dipeptides during chlorination: a computational study. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:2345-2356. [PMID: 36281824 DOI: 10.1039/d2em00321j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Chlorinated amino acids and peptides, as the model modified protein structures relevant to pathogen inactivation and an emerging class of disinfection byproducts (DBPs) with potential health risks to humans, have attracted much attention. However, due to a large variety of peptides (over 600) identified in source water and most of them featuring multiple reaction sites, it is a huge challenge to identify all the chlorinated amino acids and peptides. As a good complement to the experiment, quantum chemical computation can be used to uncover the chlorination sites and chlorinated products. In this study, frequently detected tyrosine (Tyr) and tyrosine-amide (Tyr-Am) as well as N-acetyl-tyrosine (NacTyr) were chosen as the model amino acid and model dipeptides, respectively. The results indicate that the kinetic reactivity order of reactive sites with estimated apparent rate constants (kobs-est, in M-1 s-1) is amino N (107-8) ≫ mono-chlorinated amino N (101-3) >/≈ phenol ortho-C (100-3) ≫ meta-C (10-3), and phenol ortho-C5 (102-3) > ortho-C3 (100-2) for dipeptides, while in thermodynamics, phenol C sites are more favorable than amino N sites. Moreover, due to the smaller differences of kobs-est values between the mono-chlorinated amino N and the phenol ortho-C sites in tyrosyl dipeptides compared to free Tyr, more kinds of C-chloro-tyrosyl dipeptides are likely to be generated. Additionally, a structure-kinetic reactivity relationship study reveals good correlations between lg kobs-est and NPA charges and BDEs of protons released from amino/hydroxyl groups in tyrosyl compounds rather than FED2 (HOMO). The results are helpful to further understand the reactivity of various reaction sites in peptides and identify chlorinated products from tyrosyl peptides during chlorination.
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Affiliation(s)
- Zizhang Ren
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
| | - Yue Qiu
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
| | - Mengxue Huan
- Beijing Key Laboratory of Environmental and Viral Oncology, Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, 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.
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11
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Wang Z, Xiao F, Shen X, Zhang D, Chu W, Zhao H, Zhao G. Electronic Control of Traditional Iron-Carbon Electrodes to Regulate the Oxygen Reduction Route to Scale Up Water Purification. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13740-13750. [PMID: 36130282 DOI: 10.1021/acs.est.2c03673] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Shifting four-electron (4e-) oxygen reduction in fuel cell technology to a two-electron (2e-) pathway with traditional iron-carbon electrodes is a critical step for hydroxyl radical (HO•) generation. Here, we fabricated iron-carbon aerogels with desired dimensions (e.g., 40 cm × 40 cm) as working electrodes containing atomic Fe sites and Fe3C subnanoclusters. Electron-donating Fe3C provides electrons to FeN4 through long-range activation for achieving the ideal electronic configuration, thereby optimizing the binding energy of the *OOH intermediate. With an iron-carbon aerogel benefiting from finely tuned electronic density, the selectivity of 2e- oxygen reduction increased from 10 to 90%. The resultant electrode exhibited unexpectedly efficient HO• production and fast elimination of organics. Notably, the kinetic constant kM for sulfamethoxazole (SMX) removal is 60 times higher than that in a traditional iron-carbon electrode. A flow-through pilot device with the iron-carbon aerogel (SA-Fe0.4NCA) was built to scale up micropolluted water decontamination. The initial total organic carbon (TOC) value of micropolluted water was 4.02 mg L-1, and it declined and maintained at 2.14 mg L-1, meeting the standards for drinking water quality in China. Meanwhile, the generation of emerging aromatic nitrogenous disinfection byproducts (chlorophenylacetonitriles) declined by 99.2%, satisfying the public safety of domestic water. This work provides guidance for developing electrochemical technologies to satisfy the flexible and economic demand for water purification, especially in water-scarce areas.
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Affiliation(s)
- Zining Wang
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Fan Xiao
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xuqian Shen
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Di Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Hongying Zhao
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Guohua Zhao
- Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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12
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Wu Y, Bu L, Zhu S, Chen F, Li T, Zhou S, Shi Z. Molecular transformation of algal organic matter during sequential ozonation-chlorination: Role of pre-ozonation and properties of chlorinated disinfection byproducts. WATER RESEARCH 2022; 223:119008. [PMID: 36027764 DOI: 10.1016/j.watres.2022.119008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Formation of unknown chlorinated disinfection byproducts (Cl-DBPs) during chlorination gradually raised great concern, and pre-oxidation was considered as an efficient method to minimize Cl-DBP formation. In this study, pre-ozonation of algal organic matter was investigated, to explore its impacts on Cl-DBP formation and acute toxicity during subsequent chlorination. With fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis, the conversion of algal organic matter in chlorination with/without pre-ozonation was tracked. The results show that pre-ozonation reduced the formation of trichloromethane (TCM), yet the species and intensity of unknown Cl-DBPs were significantly increased in subsequent chlorination. Meanwhile, the solution acute toxicity was higher in chlorination with pre-ozonation than in chlorination only. Besides, molecular properties of these unknown Cl-DBPs were further explored and featured. One-chlorine-containing DBPs were unsaturated high molecular-weight compounds with more CH2 structures, while two or three-chlorine-containing DBPs were mainly oxidized or saturated compounds. Of note, large amounts of one-chlorine-containing DBPs related to polycyclic aromatics and polyphenols compositions were generated, which may contribute to the high potential toxicity. Overall, the findings of this study could provide new insights into the impacts of pre-ozonation on the formation of unknown Cl-DBPs and potential toxicity during chlorination for actual application.
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Affiliation(s)
- Yuwei Wu
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Lingjun Bu
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China.
| | - Shumin Zhu
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Fan Chen
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Tianbing Li
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China
| | - Shiqing Zhou
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China.
| | - Zhou Shi
- Hunan Engineering Research Center of Water Security Technology and Application, Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, College of Civil Engineering, Hunan University, Changsha 410082, China
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13
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Zhao J, Hu S, Zhu L, Wang W. Formation of chlorinated halobenzoquinones during chlorination of free aromatic amino acids. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 825:153904. [PMID: 35189221 DOI: 10.1016/j.scitotenv.2022.153904] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Chlorinated halobenzoquinones (HBQs) widely exist in drinking water as emerging disinfection byproducts (DBPs), which have attracted significant attention due to their wide occurrence and high toxicity. In this study, the formation of chlorinated HBQs from the three free aromatic amino acids, tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe), during chlorination was investigated, the formation pathways of chlorinated HBQs were explained based on the detected intermediates and influence factors. The results revealed that four chlorinated HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,3,5-trichloro-1,4-benzoquinone, 2,3,5,6-tetrachloro-1,4-benzoquinone and 2,6-dichloro-3-methyl-1,4-benzonquinone, were formed in chlorination of the three free aromatic amino acids, and 2,6-DCBQ was the dominant species among the formed chlorinated HBQs. Of the three free aromatic amino acids, Trp and Tyr presented relatively high yields of chlorinated HBQs than Phe. Moreover, ten intermediates were successfully detected (e.g., N,2-dichloroaniline from Trp, 2,4,6-trichlorophenol from Tyr) according to the isotope and fragment information obtained using high resolution mass spectrometry. The formation pathways of chlorinated HBQs from Trp and Tyr were proposed to include electrophilic addition, electrophilic substitution, oxidation, deacidification and dehydration reaction, and further validated using theoretical calculation. The yields of chlorinated HBQs during chlorination of the free aromatic amino acids were significantly affected by free chlorine dosage, pH and temperature.
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Affiliation(s)
- Jiaxing Zhao
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Shaoyang Hu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Lizhong Zhu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Wei Wang
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
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14
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Wang K, Zhu X, Liu Z, Wang J, Chen B. Occurrence and transformation of unknown organochlorines in the wastewater treatment plant using specific Fragment-Based method with LC Q-TOF MS. WATER RESEARCH 2022; 216:118372. [PMID: 35378449 DOI: 10.1016/j.watres.2022.118372] [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: 12/03/2021] [Revised: 03/23/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
Abstract
Wastewater treatment plants (WWTPs) are important point sources of organochlorines in surface waters. However, comprehensive molecular-level understanding of the occurrence and transformation of organochlorines in WWTPs remains elusive. In this study, a specific fragment-based screening method with SWATH of LC Q-TOF MS was established to better understand the molecular composition of organochlorines. This method effectively excludes the non-chlorinated signals and provides multi-dimensional information (e.g., retention time, precursor ion mass, product ions, and molecular formula) with one injection to identify the possible structures of organochlorines. Eighty-seven organochlorines were successfully screened in practical wastewater samples, where 8 chlorinated sulfonic acids, 4 chlorophenols, 4 chlorinated benzenediols, and 6 chlorinated benzoic acids were further (tentatively) identified. Relative abundance of organochlorines showed that their occurrence was associated with the treatment units. In particular, anaerobic biological and NaClO treatment units contributed to the formation of chlorinated by-products. Most chlorinated by-products were substituted with more chlorine atoms than organochlorines from the influent. Furthermore, the relative abundance indicated that the fate of organochlorines were related to their structures. Chlorinated benzene sulfonic acids would be removed by adsorption on activated sludge. Most chlorinated benzoic acids were refractory, but some were likely to be chlorinated during the anaerobic process. Chlorophenols and chlorinated benzenediols might undergo chlorination, dealkylation/C-O bond breakage, and bromination. Our study offers a new tool to gain molecular information on organochlorines in complex environmental samples and highlights the importance of molecular structures when evaluating the fate of organochlorines and managing effluent discharge to surrounding waters.
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Affiliation(s)
- Kun Wang
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Xiangyu Zhu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Zhengzheng Liu
- Zhejiang Key Laboratory of Ecological and Environmental Monitoring, Forewarning and Quality Control, Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China
| | - Jing Wang
- Zhejiang Key Laboratory of Ecological and Environmental Monitoring, Forewarning and Quality Control, Zhejiang Ecological and Environmental Monitoring Center, Hangzhou 310012, China.
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
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15
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Wu Y, Sheng D, Wu Y, Sun J, Bu L, Zhu S, Zhou S. Molecular insights into formation of nitrogenous disinfection byproducts from algal organic matter in UV-LEDs/chlorine process based on FT-ICR analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 812:152457. [PMID: 34952064 DOI: 10.1016/j.scitotenv.2021.152457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/07/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
Eutrophication is a globally concerned issue, which brings algal cells and algal organic matter (AOM) into drinking water treatment plants. AOM is an important branch of nitrogenous disinfection byproduct (N-DBP) precursors. The variation of AOM composition in UV-LEDs/chlorine process, and its relationship with N-DBP formation still remain much uncertainty. Herein, we used fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to investigate AOM transformation in UV-LEDs/chlorine process, with UV285 and UV365 as light source, and screen for typical precursors of N-DBPs. We found that more nitrogen-containing compounds were generated after UV-LEDs/chlorine process, leading to the larger formation of N-DBPs in postchlorination. Compounds such as lignin, proteins, and amino sugars tends to be oxidized by reactive species in UV-LEDs/chlorine process. Further, compounds with higher O/C and higher weighted average double bond equivalence (DBEw) are easier to form N-DBPs, including dichloroacetonitrile and trichloronitromethane. Also, influence factors including pH, UV fluence, post-chlorination time and bromide concentration on N-DBP formation were evaluated. The results show that N-DBP formation generally followed the order of UV285/chlorine-postchlorination, UV365/chlorine-postchlorination, and direct chlorination. Our study provides comprehensive information on N-DBP formation from AOM in UV-LEDs/chlorine-postchlorination from molecular levels.
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Affiliation(s)
- Yuwei 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
| | - 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
| | - 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
| | - Julong Sun
- School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, 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
| | - 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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