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von Gunten U. Oxidation processes and me. WATER RESEARCH 2024; 253:121148. [PMID: 38387263 DOI: 10.1016/j.watres.2024.121148] [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: 11/15/2023] [Revised: 01/12/2024] [Accepted: 01/14/2024] [Indexed: 02/24/2024]
Abstract
This publication summarizes my journey in the field of chemical oxidation processes for water treatment over the last 30+ years. Initially, the efficiency of the application of chemical oxidants for micropollutant abatement was assessed by the abatement of the target compounds only. This is controlled by reaction kinetics and therefore, second-order rate constant for these reactions are the pre-requisite to assess the efficiency and feasibility of such processes. Due to the tremendous efforts in this area, we currently have a good experimental data base for second-order rate constants for many chemical oxidants, including radicals. Based on this, predictions can be made for compounds without experimental data with Quantitative Structure Activity Relationships with Hammet/Taft constants or energies of highest occupied molecular orbitals from quantum chemical computations. Chemical oxidation in water treatment has to be economically feasible and therefore, the extent of transformation of micropollutants is often limited and mineralization of target compounds cannot be achieved under realistic conditions. The formation of transformation products from the reactions of the target compounds with chemical oxidants is inherent to oxidation processes and the following questions have evolved over the years: Are the formed transformation products biologically less active than the target compounds? Is there a new toxicity associated with transformation products? Are transformation products more biodegradable than the corresponding target compounds? In addition to the positive effects on water quality related to abatement of micropollutants, chemical oxidants react mainly with water matrix components such as the dissolved organic matter (DOM), bromide and iodide. As a matter of fact, the fraction of oxidants consumed by the DOM is typically > 99%, which makes such processes inherently inefficient. The consequences are loss of oxidation capacity and the formation of organic and inorganic disinfection byproducts also involving bromide and iodide, which can be oxidized to reactive bromine and iodine with their ensuing reactions with DOM. Overall, it has turned out in the last three decades, that chemical oxidation processes are complex to understand and to manage. However, the tremendous research efforts have led to a good understanding of the underlying processes and allow a widespread and optimized application of such processes in water treatment practice such as drinking water, municipal and industrial wastewater and water reuse systems.
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Affiliation(s)
- Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Duebendorf, Switzerland; ENAC, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale, CH-1000, Lausanne, Switzerland.
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Zhang H, He Y, Liao X, Tang X, Li Q, Zou J, Jiang Z, Zhuang M, Yang Z. Feasibility of NDEA formation control from DEDTC in chlorination/chloramination by pre-ozonation: Mechanisms and influencing factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169054. [PMID: 38052386 DOI: 10.1016/j.scitotenv.2023.169054] [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: 10/11/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023]
Abstract
N-nitrosodiethylamine (NDEA), which is the most toxic nitrosamine among the 9 detected species, has been widely detected in drinking water. Amines containing diethylamine (DEA) groups in the structure would generate NDEA during the disinfection processes. The aim of this study was to evaluate the feasibility of reducing NDEA formation from a commonly used dithiocarbamate pesticide sodium diethyldithiocarbamate (DEDTC) in subsequent chlorination and chloramination by pre-ozonation. The results demonstrated that NDEA could be generated directly during ozonation, its amounts increased from 0 to 14.34 μg/L with increasing ozone dosages (0-4 mg/L), which was higher than that chlorination (2.68 μg/L) and chloramination (4.91 μg/L) when the initial concentration of DEDTC was 20 μM. Pre-ozonation significantly raised NDEA formation from 2.68 to15.32 μg/L in subsequent chlorination; and that from 4.91 to 9.54 μg/L during subsequent chloramination processes. The addition of •OH scavenger tert-butanol (tBA) increased the production of NDEA from 8.14 to 20.80 μg/L during ozonation, and that from 6.76 to17.98 μg/L in O3/HClO process, 8.74 to 17.33 μg/L in O3/NH2Cl process. Except for NO3- and CO32-, most of the co-existing substances promoted NDEA generation from DEDTC under disinfection conditions. Based on the results of Gaussian theory calculations, GC/MS and UPLC-Q-TOFMS analysis, the influencing mechanisms of pre-ozonation on NDEA generation in the subsequent disinfection process were proposed. In addition, not only acute/chronic toxicity calculation but also luminescent bacteria test was performed to assess the possibility of pre-ozonation on the risk control of DEDTC. The research results fill a gap in the control of NDEA pollution and help to develop a safer ozone oxidation technology.
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Affiliation(s)
- Huayu Zhang
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Yueyun He
- Xiamen Institute of Environmental Science, Xiamen 361021, China
| | - Xiaobin Liao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China.
| | - Xueping Tang
- Xiamen Institute of Environmental Science, Xiamen 361021, China
| | - Qingsong Li
- College of Environmental Sciences and Engineering, Xiamen University of Technology, Xiamen, China
| | - Jing Zou
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Zhibing Jiang
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Mazhan Zhuang
- Xiamen Institute of Environmental Science, Xiamen 361021, China
| | - Zhimin Yang
- Institute of analysis center, Huaqiao University, Fujian 361021, China
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Zhou Y, Fu J, Zeng Z, Gao Y, Zhang Z, Han B, Ma J, Jiang J. Oxidation of amine-based pharmaceuticals with unactivated peroxymonosulfate: Kinetics, mechanisms, and elimination efficiency of NDMA formation. JOURNAL OF HAZARDOUS MATERIALS 2024; 463:132961. [PMID: 37951171 DOI: 10.1016/j.jhazmat.2023.132961] [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: 05/06/2023] [Revised: 10/24/2023] [Accepted: 11/07/2023] [Indexed: 11/13/2023]
Abstract
Amine-based pharmaceuticals are a significant class of N-nitrosodimethylamine (NDMA) precursors. This study investigated the use of unactivated peroxymonosulfate (PMS) to control amine-based pharmaceuticals and their NDMA formation potential. Kinetic analysis and product identification revealed that sumatriptan and doxylamine primarily underwent reactions at their tertiary amine group, while ranitidine and nizatidine had both tertiary amine and thioether group as reaction sites. The NDMA formation from sumatriptan and doxylamine during post-chloramination was significantly reduced with the abatement of the parent contaminants, while the formation of NDMA remained high even if full abatement of ranitidine and nizatidine was achieved. Product formation kinetics and reference standard tests revealed the great contribution of transformation products to NDMA formation. Ranitidine could be oxidized to sulfoxide-type product ranitidine-SO and N-oxide type product ranitidine-NO. Ranitidine-SO exhibited a high NDMA yield comparable to that of ranitidine (>90%), while ranitidine-NO showed a low NDMA yield (2%). With further oxidation of ranitidine-SO at the tertiary amine group, NDMA formation was reduced by more than 90%. The underlying mechanism for the importance of the tertiary amine group in NDMA formation was demonstrated by quantum chemical calculation. These findings underscore the potential of PMS pre-oxidation on NDMA control.
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Affiliation(s)
- Yang Zhou
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Junhao Fu
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Zhu Zeng
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Yuan Gao
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China.
| | - Zhong Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China.
| | - Bin Han
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Jinxing Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Jin Jiang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
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Li W, Han J, Zhang X, Chen G, Yang Y. Contributions of Pharmaceuticals to DBP Formation and Developmental Toxicity in Chlorination of NOM-containing Source Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18775-18787. [PMID: 37505917 DOI: 10.1021/acs.est.3c00742] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Pharmaceuticals have been considered a priority group of emerging micropollutants in source waters in recent years, while their role in the formation and toxicity of disinfection byproducts (DBPs) during chlorine disinfection remains largely unclear. In this study, the contributions of natural organic matter (NOM) and pharmaceuticals (a mixture of ten representative pharmaceuticals) to the overall DBP formation and toxicity during drinking water chlorination were investigated. By innovatively "normalizing" chlorine exposure and constructing a kinetic model, we were able to differentiate and evaluate the contributions of NOM and pharmaceuticals to the total organic halogen (TOX) formation for source waters that contained different levels of pharmaceuticals. It was found that at a chlorine contact time of 1.0 h, NOM (2 mg/L as C) and pharmaceuticals (total 0.0062-0.31 mg/L as C) contributed 79.8-99.5% and 0.5-20.2%, respectively, of TOX. The toxicity test results showed that the chlorination remarkably increased the toxicity of the pharmaceutical mixture by converting the parent compounds into more toxic pharmaceutical-derived DBPs, and these DBPs might contribute significantly to the overall developmental toxicity of chlorinated waters. This study highlights the non-negligible role of pharmaceuticals in the formation and toxicity of overall DBPs in chlorinated drinking water.
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Affiliation(s)
- Wanxin Li
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR 00000, China
| | - Jiarui Han
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR 00000, China
| | - Xiangru Zhang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR 00000, China
| | - Guanghao Chen
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch), and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong SAR 00000, China
| | - Yun Yang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR 00000, China
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Gao M, Liao X, Yu J, Lin X, Qi H, Shen L, Liu S, Yang Z. Exploring Br -'s roles on non-brominated NDMA formation during ozonation: Reactive oxygen species contribution and brominated intermediate path validation. JOURNAL OF HAZARDOUS MATERIALS 2023; 444:130205. [PMID: 36399819 DOI: 10.1016/j.jhazmat.2022.130205] [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: 08/13/2022] [Revised: 10/11/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
Bromide ions (Br-) affected non-brominated nitroso-dimethylamine (NDMA) formation during ozonation, but the mechanism is still unclear. 1,1,1',1'-tetramethyl-4,4'-(methylene-di-p-phenylene) di-semicarbazide (TMDS) was chosen to further probe this problem. The results indicated that low levels of Br- (≤20 μM) enhanced NDMA from 3.27 to 7.56 μg/L, while its amount slightly dropped to 6.22 μg/L raising Br- to 100 μM. It was experimentally verified that intermediates 1,1-dimethylsemicarbazide (DMSC) and 1,1-dimethylhydrazine (UDMH) played important roles on promoting NDMA generation, whose contribution rates were 40.2% and 32.2%, respectively. The brominated substances with higher NDMA molar yields were detected. ∙OH reduced NDMA formation without Br-, while it played promotion role with Br-; the corresponding contribution rates were - 26.9% and 29.2%, respectively. No matter with or without Br-, both ∙O2- and lO2 brought a boost to NDMA formation, their contribution ratios were 34.9% and 58.1% without Br-, while raised significantly to 64.6% and 81.5% when Br- existed. Br- not only facilitated NDMA formation, but also benefited the degradation of TMDS. Based on the calculation results and intermediates detected, the influence mechanisms of Br- were proposed. The results would provide theoretical basis and technical guarantee for treating NDMA precursors and bromide co-existing water in the future.
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Affiliation(s)
- Menglan Gao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering,Huaqiao University, Fujian 361021, China
| | - Xiaobin Liao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering,Huaqiao University, Fujian 361021, China.
| | - Jing Yu
- Institute of Municipal and Environmental Engineering, College of Civil Engineering,Huaqiao University, Fujian 361021, China
| | - Xinna Lin
- Institute of Municipal and Environmental Engineering, College of Civil Engineering,Huaqiao University, Fujian 361021, China
| | - Huan Qi
- College of Textiles and Appearl, Quanzhou Normal University, Fujian 362002, China
| | - Linlu Shen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 195000, China
| | - Shupo Liu
- Institute of Municipal and Environmental Engineering, College of Civil Engineering,Huaqiao University, Fujian 361021, China
| | - Zhimin Yang
- Institute of analysis center, Huaqiao University, Fujian 361021, China
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Li W, Zhang X, Han J. Formation of Larger Molecular Weight Disinfection Byproducts from Acetaminophen in Chlorine Disinfection. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:16929-16939. [PMID: 36409822 DOI: 10.1021/acs.est.2c06394] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Acetaminophen is widely used to treat mild to moderate pain and to reduce fever. Under the worldwide COVID-19 pandemic, this over-the-counter pain reliever and fever reducer has been drastically consumed, which makes it even more abundant than ever in municipal wastewater and drinking water sources. Chlorine is the most widely used oxidant in drinking water disinfection, and chlorination generally causes the degradation of organic compounds, including acetaminophen. In this study, a new reaction pathway in the chlorination of acetaminophen, i.e., oxidative coupling reactions via acetaminophen radicals, was investigated both experimentally and computationally. Using an ultraperformance liquid chromatograph coupled to an electrospray ionization-triple quadrupole mass spectrometer, we detected over 20 polymeric products in chlorinated acetaminophen samples, some of which have structures similar to the legacy pollutants "polychlorinated biphenyls". Both C-C and C-O bonding products were found, and the corresponding bonding processes and kinetics were revealed by quantum chemical calculations. Based on the product confirmation and intrinsic reaction coordinate computations, a pathway for the formation of the polymeric products in the chlorination of acetaminophen was proposed. This study suggests that chlorination may cause not only degradation but also upgradation of a phenolic compound or contaminant.
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Affiliation(s)
- Wanxin Li
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR00000, China
| | - Xiangru Zhang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR00000, China
| | - Jiarui Han
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR00000, China
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Wenzel J, Schmidt F, Blumrich M, Amberg A, Czich A. Predicting DNA-Reactivity of N-Nitrosamines: A Quantum Chemical Approach. Chem Res Toxicol 2022; 35:2068-2084. [PMID: 36302168 DOI: 10.1021/acs.chemrestox.2c00217] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
N-Nitrosamines (NAs) are a class of reactive organic chemicals that humans may be exposed to from environmental sources, food but also impurities in pharmaceutical preparations. Some NAs were identified as DNA-reactive mutagens and many of those have been classified as probable human carcinogens. Beyond high-potency mutagenic carcinogens that need to be strictly controlled, NAs of low potency need to be considered for risk assessment as well. NA impurities and nitrosylated products of active pharmaceutical ingredients (APIs) often arise from production processes or degradation. Most NAs require metabolic activation to ultimately become carcinogens, and their activation can be appropriately described by first-principles computational chemistry approaches. To this end, we treat NA-induced DNA alkylation as a series of subsequent association and dissociation reaction steps that can be calculated stringently by density functional theory (DFT), including α-hydroxylation, proton transfer, hydroxyl elimination, direct SN2/SNAr DNA alkylation, competing hydrolysis and SN1 reactions. Both toxification and detoxification reactions are considered. The activation reactions are modeled by DFT at a high level of theory with an appropriate solvent model to compute Gibbs free energies of the reactions (thermodynamical effects) and activation barriers (kinetic effects). We study congeneric series of aliphatic and cyclic NAs to identify trends. Overall, this work reveals detailed insight into mechanisms of activation for NAs, suggesting that individual steric and electronic factors have directing and rate-determining influence on the formation of carbenium ions as the ultimate pro-mutagens and thus carcinogens. Therefore, an individual risk assessment of NAs is suggested, as exemplified for the complex API-like 4-(N-nitroso-N-methyl)aminoantipyrine which is considered as low-potency NA by in silico prediction.
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Affiliation(s)
- Jan Wenzel
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Friedemann Schmidt
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Matthias Blumrich
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Alexander Amberg
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
| | - Andreas Czich
- Sanofi, R&D, Preclinical Safety, Industriepark Höchst, Industriepark Höchst, 65926Frankfurt am Main, Germany
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Song Y, Feng S, Qin W, Li J, Guan C, Zhou Y, Gao Y, Zhang Z, Jiang J. Formation mechanism and control strategies of N-nitrosodimethylamine (NDMA) formation during ozonation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153679. [PMID: 35131246 DOI: 10.1016/j.scitotenv.2022.153679] [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: 10/13/2021] [Revised: 01/06/2022] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
This review summarizes major findings over the last decade related to N-nitrosodimethylamine (NDMA) formed upon ozonation, which was regarded as highly toxic and carcinogenic disinfection by-products. The reaction kinetics, chemical yields and mechanisms were assessed for the ozonation of potential precursors including dimethylamine (DMA), N,N-dimethylsulfamide, hydrazines, N-containing water and wastewater polymers, dyes containing a dimethylamino function, N-functionalized carbon nanotubes, guanidine, and phenylurea. The effects of bromide on the NDMA formation during ozonation of different types of precursors were also discussed. The mechanism for NDMA formation during ozonation of DMA was re-summarized and new perspectives were proposed to assess on this mechanism. Effect of hydroxyl radicals (•OH) on NDMA formation during ozonation was also discussed due to the noticeable oxidation of NDMA by •OH. Surrogate parameters including nitrate formation and UV254 after ozonation may be useful parameters to estimate NDMA formation for practical application. The strategies for NDMA formation control were proposed through improving the ozonation process such as ozone/hydrogen peroxide, ozone/peroxymonosulfate and catalytic ozonation process based on membrane pores aeration (MEMBRO3X).
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Affiliation(s)
- Yang Song
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Sha Feng
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Wen Qin
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China
| | - Juan Li
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Chaoting Guan
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Yang Zhou
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Yuan Gao
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Zhong Zhang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Jin Jiang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
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Lim S, Shi JL, von Gunten U, McCurry DL. Ozonation of organic compounds in water and wastewater: A critical review. WATER RESEARCH 2022; 213:118053. [PMID: 35196612 DOI: 10.1016/j.watres.2022.118053] [Citation(s) in RCA: 99] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/05/2022] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Ozonation has been applied in water treatment for more than a century, first for disinfection, later for oxidation of inorganic and organic pollutants. In recent years, ozone has been increasingly applied for enhanced municipal wastewater treatment for ecosystem protection and for potable water reuse. These applications triggered significant research efforts on the abatement efficiency of organic contaminants and the ensuing formation of transformation products. This endeavor was accompanied by developments in analytical and computational chemistry, which allowed to improve the mechanistic understanding of ozone reactions. This critical review assesses the challenges of ozonation of impaired water qualities such as wastewaters and provides an up-to-date compilation of the recent kinetic and mechanistic findings of ozone reactions with dissolved organic matter, various functional groups (olefins, aromatic compounds, heterocyclic compounds, aliphatic nitrogen-containing compounds, sulfur-containing compounds, hydrocarbons, carbanions, β-diketones) and antibiotic resistance genes.
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Affiliation(s)
- Sungeun Lim
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf CH-8600, Switzerland
| | - Jiaming Lily Shi
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf CH-8600, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
| | - Daniel L McCurry
- Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA, United States.
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Dwinandha D, Zhang B, Fujii M. Prediction of reaction mechanism for OH radical-mediated phenol oxidation using quantum chemical calculation. CHEMOSPHERE 2022; 291:132763. [PMID: 34740699 DOI: 10.1016/j.chemosphere.2021.132763] [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: 06/15/2021] [Revised: 10/29/2021] [Accepted: 10/31/2021] [Indexed: 06/13/2023]
Abstract
Understanding the reaction mechanism of OH•-mediated oxidation of organic micropollutants (OMPs) contributes to the assessment and development of advanced oxidation processes (AOPs) for removal of OMPs in water environment. In this study, a theoretical approach using quantum chemical calculation (QCC) was employed to investigate the prediction accuracy of the reaction mechanism (i.e., reaction site and rate) for OH•-mediated oxidation of phenol, where the hydroquinone and catechol are generated as transformation products (TPs) via radical and electrophilic reactions. We compared three different levels of theory (Hartree-Fock, B3LYP, and M06-2X) with 6-311 + G (2d,2p)/SMD, and the reaction site and rate constants were predicted by the Fukui function and transition state theory, respectively. Overall, the prediction accuracy of the TPs formation mechanism was the highest in the calculations using M06-2X. For example, the initial OH• addition to phenol was predicted to occur with a probability of 77% for the ortho position and 23% for the para position, which was consistent with the experimental observation. By applying the transition state theory, the rate constants toward TPs formation pathway can be reasonably reproduced, suggesting that M06-2X has an effective function for polycyclic reactions. However, the observed discrepancies in rate constants are inferred from dispersion effects and the multi-reference property in the computational system or derived from mismatch of target reactions between theoretical calculations and experiments. Overall, this study provides an insight into QCC application for investigating the formation mechanism of TPs in AOPs for removal of OMPs in water environment.
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Affiliation(s)
- Dhimas Dwinandha
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan
| | - Bei Zhang
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan
| | - Manabu Fujii
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan.
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Huang Y, He Z, Liao X, Cheng Y, Qi H. NDMA reduction mechanism of UDMH by O 3/PMS technology. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 805:150418. [PMID: 34818816 DOI: 10.1016/j.scitotenv.2021.150418] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Carcinogenic N, N-Dimethylnitrosamine (NDMA) has been reported to generate significantly during ozonation of fuel additive unsymmetrical dimethylhydrazine (UDMH), the combined ozone/Peroxy-Monosulfate (O3/PMS) technology was tried for reducing its formation in this study. The influence of PMS dosages, ozone concentrations, pH, Br- and humic acid (HA) on NDMA formation from UDMH were investigated. In addition, the reduction mechanisms were explored by intermediates identification and Gaussian calculation. The results demonstrated that O3/PMS technology was effective on NDMA reduction, reaching an efficiency of 81% with 80 μM PMS. Higher NDMA reduction rates were achieved by O3/PMS with increasing pH within the scope of research (from 5 to 9), achieving a maximum of 69.9% at pH 9. The presence of bromide ion facilitated NDMA generation during ozonation, but the reduction efficiency by O3/PMS slightly improved from 66.3% to 70.6%. The presence of HA reduced NDMA formation in O3/PMS system. The contribution of SO4•- on NDMA reduction accounted for ~64%, which was higher than that of •OH (41.4%); however, its promotion role on conversing UDMH to NDMA was lower than O3. Therefore, the technology could reduce NDMA formation effectively. In addition, the results of Gaussian calculation manifested that the N atom in -NH2 group of UDMH was easily attacked not only by •OH but also by O3, so it is the key path that determines final NDMA formation. This study would provide reference for reducing NDMA formation during ozonation of UDMH-containing water matrixes.
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Affiliation(s)
- Yongjun Huang
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Zixiang He
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Xiaobin Liao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China.
| | - Yusheng Cheng
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Huan Qi
- College of Textiles and Appearl, Quanzhou Normal University, Fujian 362000, China
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12
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Gao M, Jiang Z, Liao X, Bai X, Qi H, Zou J, Cao W. Validation of the promotion mechanism between bromide and UDMH to form NDMA during ozonation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148316. [PMID: 34147807 DOI: 10.1016/j.scitotenv.2021.148316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
Unsymmetrical dimethylhydrazine (UDMH) is found to generate substantial carcinogenic nitroso-dimethylamine (NDMA) during ozonation, moreover, its formation is promoted by ubiquitous bromide ions (Br-) in water matrixes, but the mechanism is still unclear. In this study, effects of Br- on NDMA formation during ozonation of UDMH were studied, meanwhile, its promotion pathways were also determined. The results demonstrated that Br- promoted NDMA formation from UDMH during ozonation, the formation rate constant with Br- is over 7 times of that without Br-. NDMA amount raised from 142.5 to 327.5 μg/L when Br- dosages increased from 0 to 100 μM. No matter with or without Br-, the augment of O3 dosages facilitated NDMA formation; the maximum value was achieved at pH 8. NDMA decreased dramatically from 173.8 to 123.5 μg/L with HCO3- raising from 0 to 160 μM, while increasing remarkably to 222.5 μg/L with SO42- dosing. In addition, NOM inhibited NDMA formation from UDMH during ozonation. The mass spectrum of LC-MS/MS verified that the generation of Br-UDMH was main cause for promoting NDMA formation. Moreover, hypobromous acid (HBrO) was confirmed to be responsible for Br-UDMH formation. In addition, the position that oxidants and Br- attacked was demonstrated based on Gaussian calculation. The results of this study could provide theoretical basis for the application of ozonation in bromine-containing water matrixes.
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Affiliation(s)
- Menglan Gao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Zhibin Jiang
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Xiaobin Liao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China.
| | - Xingji Bai
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Huan Qi
- College of Textiles and Appearl, Quanzhou Normal University, Fujian 362002, China.
| | - Jing Zou
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
| | - Wei Cao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Fujian 361021, China
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13
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Rothe LE, Botha TL, Feld CK, Weyand M, Zimmermann S, Smit NJ, Wepener V, Sures B. Effects of conventionally-treated and ozonated wastewater on mortality, physiology, body length, and behavior of embryonic and larval zebrafish (Danio rerio). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117241. [PMID: 33975214 DOI: 10.1016/j.envpol.2021.117241] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/31/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
To date, micropollutants from anthropogenic sources cannot be completely removed from effluents of wastewater treatment plants and therefore enter freshwater systems, where they may impose adverse effects on aquatic organisms, for example, on fish. Advanced treatment such as ozonation aims to reduce micropollutants in wastewater effluents and, thus, to mitigate adverse effects on the environment. To investigate the impact and efficiency of ozonation, four different water types were tested: ozonated wastewater (before and after biological treatment), conventionally-treated wastewater, and water from a river (River Ruhr, Germany) upstream of the wastewater treatment plant effluent. Zebrafish (Danio rerio) embryos were used to study lethal and sublethal effects in a modified fish early life-stage test. Mortality occurred during exposure in the water samples from the wastewater treatment plant and the river in the first 24 h post-fertilization, ranging from 12% (conventional wastewater) to 40% (river water). Regarding sublethal endpoints, effects compared to the negative control resulted in significantly higher heart rates (ozonated wastewater), and significantly reduced swimming activity (highly significant in ozonated wastewater and ozone reactor water, significant in only the last time interval in river water). Moreover, the respiration rates were highly increased in both ozonated wastewater samples in comparison to the negative control. Significant differences between the ozonated wastewater samples occurred in the embryonic behavior and heart rates, emphasizing the importance of subsequent biological treatment of the ozonated wastewater. Only the conventionally-treated wastewater sample did not elicit negative responses in zebrafish, indicating that the discharge of conventional wastewater poses no greater risk to embryonic and larval zebrafish than water from the river Ruhr itself. The sublethal endpoints embryonic- and larval behavior, heart rates, and respiration were found to be the most sensitive endpoints in this fish early life-stage test and can add valuable information on the toxicity of environmental samples.
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Affiliation(s)
- Louisa E Rothe
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany.
| | - Tarryn L Botha
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman St, Potchefstroom, 2520, South Africa; Agricultural Research Council - Soil, Climate and Water, Private Bag X79, Pretoria, 0001, South Africa
| | - Christian K Feld
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany
| | - Michael Weyand
- Ruhrverband, Department of River Basin Management, Kronprinzenstr. 37, 45128, Essen, Germany
| | - Sonja Zimmermann
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany; Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman St, Potchefstroom, 2520, South Africa
| | - Nico J Smit
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman St, Potchefstroom, 2520, South Africa
| | - Victor Wepener
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman St, Potchefstroom, 2520, South Africa
| | - Bernd Sures
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany
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14
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Barrios B, Mohrhardt B, Doskey PV, Minakata D. Mechanistic Insight into the Reactivities of Aqueous-Phase Singlet Oxygen with Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8054-8067. [PMID: 34096699 DOI: 10.1021/acs.est.1c01712] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Singlet oxygen (1O2) is a selective reactive oxygen species that plays a key role for the fate of various organic compounds in the aquatic environment under sunlight irradiation, engineered water oxidation systems, atmospheric water droplets, and biomedical systems. While the initial rate-determining charge-transfer reaction mechanisms and kinetics of 1O2 have been studied extensively, no comprehensive studies have been performed to elucidate the reaction mechanisms with organic compounds that have various functional groups. In this study, we use density functional theory calculations to determine elementary reaction mechanisms with a wide variety of organic compounds. The theoretically calculated aqueous-phase free energies of activation of single electron transfer and 1O2 addition reactions are compared to the experimentally determined rate constants in the literature to determine linear free-energy relationships. The theoretically calculated free energies of activation for the groups of phenolates and phenols show excellent correlations with the Hammett constants that accept electron densities by through-resonance. The dominant elementary reaction mechanism is discussed for each group of compounds. As a practical implication, we demonstrate the fate of environmentally relevant organic compounds induced by photochemically produced intermediate species at different pH and evaluate the impact of predicting rate constants to the half-life.
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Affiliation(s)
- Benjamin Barrios
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Benjamin Mohrhardt
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Paul V Doskey
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Daisuke Minakata
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
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15
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Wirzberger V, Klein M, Woermann M, Lutze HV, Sures B, Schmidt TC. Matrix composition during ozonation of N-containing substances may influence the acute toxicity towards Daphnia magna. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142727. [PMID: 33129546 DOI: 10.1016/j.scitotenv.2020.142727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/01/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
Micropollutants reach the aquatic environment through wastewater treatment plant effluents. Ozonation, applied in wastewater treatment for micropollutants abatement, can yield transformation products (TP), which might be of ecotoxicological concern. Previous studies on TP formation were mostly performed in ultrapure water. However, the water matrix can have a substantial influence and lead to unpredictable yields of TPs with toxicological potential. In this study the acute toxicity (immobilization) of the parent substances (isoproturon and metoprolol) and also of available TPs of isoproturon, metoprolol and diclofenac towards Daphnia magna (D. magna) were investigated. Further, the acute toxicity of TP mixtures, formed during ozonation of isoproturon, metoprolol and diclofenac was evaluated in the following systems: in the presence of radical scavengers (tert-butanol and dimethyl sulfoxide) and in the presence of hypobromous acid (HOBr), a secondary oxidant in ozonation. For all tested substances and TP standards, except 2,6-dichloroaniline (EC50 1.02 mg/L (48 h)), no immobilization of D. magna was detected. Ozonated pure water and wastewater did not show an immobilization effect either. After ozonation of diclofenac in the presence of dimethyl sulfoxide 95% (48 h) of the daphnids were immobile. Ozonation of parent substances, after the reaction with HOBr, showed no effect for isoproturon but a high effect on D. magna for diclofenac (95% immobilization (48 h)) and an even higher effect for metoprolol (100% immobilization (48 h)). These results emphasize that complex water matrices can influence the toxicity of TPs as shown in this study for D. magna.
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Affiliation(s)
- Vanessa Wirzberger
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany
| | - Michelle Klein
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Marion Woermann
- Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany; Aquatic Ecology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Holger V Lutze
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany; Technical University Darmstadt, Franziska-Braun-Straße 3, 64287 Darmstadt, Germany; IWW Water Centre, Moritzstraße 26, 45476, Mülheim an der Ruhr, Germany.
| | - Bernd Sures
- Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany; Aquatic Ecology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany; IWW Water Centre, Moritzstraße 26, 45476, Mülheim an der Ruhr, Germany.
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16
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Wu Z, Shang C, Wang D, Zheng S, Wang Y, Fang J. Rapid degradation of dichloroacetonitrile by hydrated electron (e aq-) produced in vacuum ultraviolet photolysis. CHEMOSPHERE 2020; 256:126994. [PMID: 32445996 DOI: 10.1016/j.chemosphere.2020.126994] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/02/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Dichloroacetonitrile (DCAN) is one of the most toxic and common nitrogenous disinfection by-products in water treatment. It is necessary to understand how this compound can be removed. In this study, the effectiveness of vacuum ultraviolet (VUV) at 185 nm was evaluated to destroy DCAN. When water is exposed to VUV, hydroxyl radicals (HO•), hydrogen atoms (H•), and hydrated electrons (eaq-) are generated. The individual contributions of these reactive species to DCAN degradation were distinguished using multiple scavengers. The results showed that eaq- was the most important species for DCAN degradation. The second-order rate constant for eaq- reacting with DCAN was calculated to be 3.16 × 1010 M-1s-1 using a quantitative structure-activity relationship (QSAR) method adopted from previous study, and determined to be 3.76 (±0.02) × 1010 M-1s-1 by competition kinetics. Although dissolved oxygen (DO) at 8 mg/L consumed 86% eaq-, the rest of eaq- still led to 93% removal of DCAN within 20 min. Chloride was the major inorganic product of DCAN degradation, while nitrate and nitrite were minor products. Quantum chemical calculation and mass balance calculation under an oxygen free condition further suggested that cleavage of C-Cl bonds was the major pathway by eaq- attack. This study demonstrated the significant role of eaq- in micropollutant destruction during VUV treatment.
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Affiliation(s)
- Zihao Wu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Chii Shang
- Department of Civil and Environmental Engineering, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | | | - Shanshan Zheng
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Yuge Wang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China
| | - Jingyun Fang
- 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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17
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Tentscher PR, Lee M, von Gunten U. Micropollutant Oxidation Studied by Quantum Chemical Computations: Methodology and Applications to Thermodynamics, Kinetics, and Reaction Mechanisms. Acc Chem Res 2019; 52:605-614. [PMID: 30829468 DOI: 10.1021/acs.accounts.8b00610] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The abatement of organic micropollutants during oxidation processes has become an emerging issue for various urban water systems such as drinking water, wastewater, and water reuse. Reaction kinetics and mechanisms play an important role in terms of efficiency of these processes and the formation of transformation products, which are controlled by functional groups in the micropollutants and the applied oxidants. So far, the kinetic and mechanistic information on the underlying reactions was obtained by experimental studies; additionally, predictive quantitative structure-activity relationships (QSARs) were applied to determine reaction kinetics for the oxidation of emerging compounds. Since this experimental approach is very laborious and there are tens of thousands potential contaminants, alternative strategies need to be developed to predict the fate of micropollutants during oxidative water treatment. Due to significant developments in quantum chemical (QC) computations in recent years and increased computational capacity, QC-based methods have become an alternative or a supplement to the current experimental approach. This Account provides a critical assessment of the current state-of-the-art of QC-based methods for the assessment of oxidation of micropollutants. Starting from a given input structure, QC computations need to locate energetic minima on the potential energy surface (PES). Then, useful thermodynamic and kinetic information can be estimated by different approaches: Experimentally determined reaction mechanisms can be validated by identification of transition structures on the PES, which can be obtained for addition reactions, heavy atom transfer (Cl+, Br+, O·) and H atom transfer (simultaneous proton and electron transfer) reactions. However, transition structures in the PES cannot be obtained for e--transfer reactions. Second-order rate constants k for the reactions of micropollutants with chemical oxidants can be obtained by ab initio calculations or by QSARs with various QC descriptors. It has been demonstrated that second-order rate constants from ab initio calculations are within factors 3-750 of the measured values, whereas QSAR-based methods can achieve factors 2-4 compared to the experimental data. The orbital eigenvalue of the highest occupied molecular orbital ( EHOMO) is the most commonly used descriptor for QSAR-based computations of k-values. In combination with results from experimental studies, QC computations can also be applied to investigate reaction mechanisms for verification/understanding of oxidative mechanisms, calculation of branching ratios or regioselectivity, evaluation of the experimental product distribution and assessment of substitution effects. Furthermore, other important physical-chemical constants such as unknown equilibria for species, which are not measurable due to low concentrations, or p Ka values of reactive transient species can be estimated. With further development of QC-based methods, it will become possible to implement kinetic and mechanistic information from such computations in in silico models to predict oxidative transformation of micropollutants. Such predictions can then be complemented by tailored experimental studies to confirm/falsify the computations.
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Affiliation(s)
- Peter R. Tentscher
- Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg East, Denmark
| | - Minju Lee
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Duebendorf, Switzerland
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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18
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Dong M, Liu YD, Zhong R. NDMA formation mechanisms from typical hydrazines and hydrazones during ozonation: A computational study. JOURNAL OF HAZARDOUS MATERIALS 2019; 366:370-377. [PMID: 30544038 DOI: 10.1016/j.jhazmat.2018.12.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/01/2018] [Accepted: 12/03/2018] [Indexed: 06/09/2023]
Abstract
N-nitrosodimethylamine (NDMA) as the most frequently detected disinfection by-product has aroused widespread concern due to its unusually high carcinogenicity, however, there is still limited understanding of its formation mechanisms. In this study, the formation mechanisms of NDMA from some typical hydrazines and hydrazones with high NDMA conversion yields (60%∼90%) during ozonation, i.e., unsymmetrical dimethylhydrazine (UDMH), 1-formyl-2,2-dimethylhydrazine (FDMH), formaldehyde dimethylhydrazone (FDH) and acetone dimethylhydrazone (ADMH), were investigated by using DFT method with the M05 functional. A new NDMA formation mechanism from hydrazines during ozonation was proposed, in which the initial step is hydrogen abstraction rather than previously reported oxygen addition. For hydrazones, the C atom of the -N = C moiety in hydrazones is preferred to be attacked by ozone to generate N,N-dimethylaminonitrene (DMAN), which is an important intermediate in NDMA formation during ozonation. Moreover, the reactivity order of the following H atoms in hydrogen/hydride ion abstraction (HA) by ozone is -NH2 > -N(CH3)2 > -CO-NH ∼ =C(CH3)2 > =CH-. Additionally, formation pathways of some experimentally detected compounds, i.e., HOOOH, HOOH and HCOH, in the ozonation of hydrazine were elucidated in this study. The results are expected to expand our understanding of NDMA formation mechanisms and ozone reaction characteristics.
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Affiliation(s)
- Meng Dong
- Beijing Key Laboratory of Environmental and Viral Oncology, College of Life Science & Bioengineering, Beijing University of Technology, Beijing, 100124, 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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Shen L, Liao X, Qi H, Zhao L, Li F, Yuan B. NDMA formation from 4,4'-hexamethylenebis (HDMS) during ozonation: influencing factors and mechanisms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:1584-1594. [PMID: 30443725 DOI: 10.1007/s11356-018-3684-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
N-nitrosodimethylamine (NDMA), a toxic disinfection byproduct commonly associated with chloramination, has recently been found to form from an anti-yellowing agent (4,4'-hexamethylenebis (1,1-dimethylsemicarbazide) (HDMS)) during ozonation but the mechanisms are unclear. In this paper, the potential roles of molecular ozone (O3) and hydroxyl radical (∙OH) on NDMA formation from HDMS were investigated under various oxidation conditions (ozone dosages, pH) and different components in water (bromide ion (Br-), bicarbonate ion (HCO3-), sulfate ion (SO42-), and humic acid (HA), as well as natural organic matter (NOM) from a lake). Moreover, HDMS transformation pathways by ozonation were determined. The results indicated that the formation of NDMA was enhanced through the combined effect of O3 and ∙OH compared to that by O3 alone (addition of tert-butyl alcohol (tBA) as ∙OH scavenger). ∙OH itself cannot generate NDMA directly; however, it can transform HDMS to intermediates with higher NDMA yield than parent compound. The NDMA generation was affected (small dosages promoted but high dosages inhibited) by HA or Br- no matter with or without tBA. The presence of SO42- and HCO3- ions lowered NDMA formation through ∙OH scavenging effect. Increasing pH not only increased degradation rate constant by enhancing ∙OH generation but also affected HDMS dissociation ratio, reaching the maximum NDMA formation at pH 7-8. Natural constituents in selected water matrix inhibited NDMA formation. Impacts of these influencing factors on NDMA formation by only O3 however were significantly less pronounced over that by the joint roles of O3 and ∙OH. Based on the result of Q-TOF, LC/MS/MS, and GC/MS, the possible transformation pathways of HDMS by ozonation were proposed. The NDMA enhancement mechanism by the combined effect of O3 and ∙OH can be attributed to greater amounts of intermediates with higher NDMA yield (such as unsymmetrical dimethylhydrazine (UDMH)) produced. These findings provide new understanding of NDMA formation upon ozonation of typical amine-based compounds.
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Affiliation(s)
- Linlu Shen
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Xiamen, 361021, Fujian, China
| | - Xiaobin Liao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Xiamen, 361021, Fujian, China.
| | - Huan Qi
- College of Textiles and Appearl, Quanzhou Normal University, Quanzhou, 362002, Fujian, China
| | - Lei Zhao
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Xiamen, 361021, Fujian, China
| | - Fei Li
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Xiamen, 361021, Fujian, China
| | - Baoling Yuan
- Institute of Municipal and Environmental Engineering, College of Civil Engineering, Huaqiao University, Xiamen, 361021, Fujian, China
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20
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Knoop O, Hohrenk LL, Lutze HV, Schmidt TC. Ozonation of Tamoxifen and Toremifene: Reaction Kinetics and Transformation Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12583-12591. [PMID: 30221510 DOI: 10.1021/acs.est.8b00996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The oxidation of the two antiestrogenic pharmaceuticals tamoxifen and toremifene with ozone in water was investigated concerning kinetics, reaction pathway, and transformation product formation. For both compounds a high dependency of second order rate constants and products on pH was determined. In case of full protonation of the amine (cation) ozone attacks with a second order rate constant of 1.57 × 104 M-1 s-1 for tamoxifen and 4.37 × 103 M-1 s-1 for toremifene. The neutral tertiary amine has an unexpected high second order rate constant of 3.17 × 108 M-1 s-1 for tamoxifen and 1.46 × 108 M-1 s-1 for toremifene. For the reaction of ozone and the tertiary amine only N-oxide formation was observed. p Ka values for tamoxifen (9.49 ± 0.22) and toremifene (9.57 ± 0.22) can be reported based on experimental data. Eight transformation products (TPs) were observed and identified based on MS/MS spectra or a reference standard. Products observed derived from Criegee reaction and hydroxylation as well as N-oxide formation. Further TPs from reactions with TAM products were combinations of N-oxides, Criegee products and hydroxylation products. Thus, reaction pathways can be derived and primary and secondary TPs distinguished for the first time.
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Affiliation(s)
- Oliver Knoop
- Instrumental Analytical Chemistry , University Duisburg-Essen , Universitätsstrasse 5 , 45141 Essen , Germany
- Centre for Aquatic and Environmental Research (ZWU) , University Duisburg-Essen , Universitätsstrasse 2 , 45141 Essen , Germany
- Chair for Urban Water Systems Engineering , Technical University of Munich , Am Coulombwall 3 , 85748 Garching , Germany
| | - Lotta L Hohrenk
- Instrumental Analytical Chemistry , University Duisburg-Essen , Universitätsstrasse 5 , 45141 Essen , Germany
| | - Holger V Lutze
- Instrumental Analytical Chemistry , University Duisburg-Essen , Universitätsstrasse 5 , 45141 Essen , Germany
- Centre for Aquatic and Environmental Research (ZWU) , University Duisburg-Essen , Universitätsstrasse 2 , 45141 Essen , Germany
- IWW Water Centre , Moritzstr. 26 , Mülheim an der Ruhr , Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry , University Duisburg-Essen , Universitätsstrasse 5 , 45141 Essen , Germany
- Centre for Aquatic and Environmental Research (ZWU) , University Duisburg-Essen , Universitätsstrasse 2 , 45141 Essen , Germany
- IWW Water Centre , Moritzstr. 26 , Mülheim an der Ruhr , Germany
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21
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Knoop O, Woermann M, Lutze HV, Sures B, Schmidt TC. Ecotoxicological effects prior to and after the ozonation of tamoxifen. JOURNAL OF HAZARDOUS MATERIALS 2018; 358:286-293. [PMID: 29990816 DOI: 10.1016/j.jhazmat.2018.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/28/2018] [Accepted: 07/01/2018] [Indexed: 06/08/2023]
Abstract
The endocrine disrupting micropollutant tamoxifen can induce several effects on aquatic organisms. It is introduced into the environment mainly by wastewater treatment plant effluents. To reduce the discharge of micropollutants into surface waters, ozonation can be used as additional wastewater treatment option. For only few transformation products (TPs) formed by ozonation ecotoxicological data are available. To enable an initial estimation of ecotoxicological potentials of the TPs formed after the ozonation of tamoxifen, acute toxicity (immobilization) to Daphnia magna and green algae growth inhibition using Desmodesmus subspicatus were determined for several ozone doses spiked at pH 3 and pH 7. The initial immobilization of D. magna by tamoxifen was not further observed after ozonation. In contrast, the green algae growth inhibition increased due to ozonation of tamoxifen. Overall, five transformation products were observed. For three TPs, positive correlations of green algae growth inhibition and peak area were determined, whereas two TPs do not induce the residual effects. Based on our observations, TP 270 can be assumed as most potent of the formed TPs concerning green algae growth inhibition. Since the effect is not induced by formed N-oxides, green algae growth inhibition could be reduced by sufficient ozone exposure during wastewater treatment.
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Affiliation(s)
- Oliver Knoop
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany
| | - Marion Woermann
- Aquatic Ecology, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany
| | - Holger V Lutze
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; IWW Water Centre, Moritzstr. 26, Mülheim an der Ruhr, Germany
| | - Bernd Sures
- Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; Aquatic Ecology, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; IWW Water Centre, Moritzstr. 26, Mülheim an der Ruhr, Germany.
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22
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Knoop O, Itzel F, Tuerk J, Lutze HV, Schmidt TC. Endocrine effects after ozonation of tamoxifen. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 622-623:71-78. [PMID: 29202370 DOI: 10.1016/j.scitotenv.2017.11.286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
Ozonation is used as additional wastewater treatment option to remove recalcitrant micropollutants. It also removes the estrogenic activity found in wastewater but not always the anti-estrogenic activity. This can be explained by an incomplete removal of anti-estrogenic micropollutants or by formation of transformation products (TPs) which retain the activity. The present study investigates the degradation of the anti-estrogenic pharmaceutical tamoxifen in pure water, regarding TP formation and related anti-estrogenic effect using Arxula adeninivorans yeast estrogen screen (A-YES). In total, five transformation products were detected: three N-oxides and two further products (TP 270 and TP 388). For the transformation product TP 270 a correlation of the extent of formation with an increase of the anti-estrogenic activity was determined, demonstrating that transformation products from ozonation can be more active in a bioassay than the parent compounds. Our study shows also that the transformation of tamoxifen to N-oxides reduces the anti-estrogenic activity. The reactivity of amines towards ozone typically increases with pH, since only deprotonated amines react with ozone. Hence, removal of the endocrine activity by N-oxide formation may be disfavored at low pH.
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Affiliation(s)
- Oliver Knoop
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany
| | - Fabian Itzel
- Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; Institut für Energie- und Umwelttechnik e.V. (IUTA, Institute of Energy and Environmental Technology), Bliersheimer Str. 58-60, 47229 Duisburg, Germany
| | - Jochen Tuerk
- Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; Institut für Energie- und Umwelttechnik e.V. (IUTA, Institute of Energy and Environmental Technology), Bliersheimer Str. 58-60, 47229 Duisburg, Germany
| | - Holger V Lutze
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; IWW Water Centre, Moritzstr. 26, 45476 Mülheim an der Ruhr, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany; Centre for Aquatic and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany; IWW Water Centre, Moritzstr. 26, 45476 Mülheim an der Ruhr, Germany.
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23
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Minakata D, Coscarelli E. Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations. Molecules 2018; 23:molecules23030539. [PMID: 29495565 PMCID: PMC6017648 DOI: 10.3390/molecules23030539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 11/16/2022] Open
Abstract
Nitrosamines are a group of carcinogenic chemicals that are present in aquatic environments that result from byproducts of industrial processes and disinfection products. As indirect and direct potable reuse increase, the presence of trace nitrosamines presents challenges to water infrastructures that incorporate effluent from wastewater treatment. Ultraviolet (UV) photolysis or UV-based advanced oxidation processes that produce highly reactive hydroxyl radicals are promising technologies to remove nitrosamines from water. However, complex reaction mechanisms involving radicals limit our understandings of the elementary reaction pathways embedded in the overall reactions identified experimentally. In this study, we perform quantum mechanical calculations to identify the hydroxyl radical-induced initial elementary reactions with N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine, and N-nitrosomethylbutylamine. We also investigate the UV-induced NDMA degradation mechanisms. Our calculations reveal that the alkyl side chains of nitrosamine affect the reaction mechanism of hydroxyl radicals with each nitrosamine investigated in this study. Nitrosamines with one- or two-carbon alkyl chains caused the delocalization of the electron density, leading to slower subsequent degradation. Additionally, three major initial elementary reactions and the subsequent radical-involved reaction pathways are identified in the UV-induced NDMA degradation process. This study provides mechanistic insight into the elementary reaction pathways, and a future study will combine these results with the kinetic information to predict the time-dependent concentration profiles of nitrosamines and their transformation products.
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Affiliation(s)
- Daisuke Minakata
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA.
| | - Erica Coscarelli
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA.
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24
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Zhang C, Li M, Han X, Yan M. Quantum Chemical Examination of the Sequential Halogen Incorporation Scheme for the Modeling of Speciation of I/Br/Cl-Containing Trihalomethanes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2162-2169. [PMID: 29357232 DOI: 10.1021/acs.est.7b03871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recently developed three-step ternary halogenation model interprets the incorporation of chlorine, bromine, and iodine ions into natural organic matter (NOM) and formation of iodine-, bromine-, and chlorine-containing trihalomethanes (THMs) based on the competition of iodine, bromine, and chlorine species at each node of the halogenation sequence. This competition is accounted for using the dimensionless ratios (denoted as γ) of kinetic rates of reactions of the initial attack sites or halogenated intermediates with chlorine, bromine, and iodine ions. However, correlations between the model predictions made and mechanistic aspects of the incorporation of halogen species need to be ascertained in more detail. In this study, quantum chemistry calculations were first used to probe the formation mechanism of 10 species of Cl-/Br-/I- THMs. The HOMO energy (EHOMO) of each mono-, bi-, or trihalomethanes were calculated by B3LYP method in Gaussian 09 software. Linear correlations were found to exist between the logarithms of experimentally determined kinetic preference coefficients γ reported in prior research and, on the other hand, differences of EHOMO values between brominated/iodinated and chlorinated halomethanes. One notable exception from this trend was that observed for the incorporation of iodine into mono- and di-iodinated intermediates. These observations confirm the three-step halogen incorporation sequence and the factor γ in the statistical model. The combined use of quantum chemistry calculations and the ternary sequential halogenation model provides a new insight into the microscopic nature of NOM-halogen interactions and the trends seen in the behavior of γ factors incorporated in the THM speciation models.
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Affiliation(s)
- Chenyang Zhang
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
| | - Maodong Li
- Center for Quantitative Biology, Peking University , Beijing 100871, China
| | - Xuze Han
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
| | - Mingquan Yan
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education , Beijing 100871, China
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25
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Sgroi M, Vagliasindi FGA, Snyder SA, Roccaro P. N-Nitrosodimethylamine (NDMA) and its precursors in water and wastewater: A review on formation and removal. CHEMOSPHERE 2018; 191:685-703. [PMID: 29078192 DOI: 10.1016/j.chemosphere.2017.10.089] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/05/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
This review summarizes major findings over the last decade related to N-Nitrosodimethylamine (NDMA) in water and wastewater. In particular, the review is focused on the removal of NDMA and of its precursors by conventional and advanced water and wastewater treatment processes. New information regarding formation mechanisms and precursors are discussed as well. NDMA precursors are generally of anthropogenic origin and their main source in water have been recognized to be wastewater discharges. Chloramination is the most common process that results in formation of NDMA during water and wastewater treatment. However, ozonation of wastewater or highly contaminated surface water can also generate significant levels of NDMA. Thus, NDMA formation control and remediation has become of increasing interest, particularly during treatment of wastewater-impacted water and during potable reuse application. NDMA formation has also been associated with the use of quaternary amine-based coagulants and anion exchange resins. UV photolysis with UV fluence far higher than typical disinfection doses is generally considered the most efficient technology for NDMA mitigation. However, recent studies on the optimization of biological processes offer a potentially lower-energy solution. Options for NDMA control include attenuation of precursor materials through physical removal, biological treatment, and/or deactivation by application of oxidants. Nevertheless, NDMA precursor identification and removal can be challenging and additional research and optimization is needed. As municipal wastewater becomes increasingly used as a source water for drinking, NDMA formation and mitigation strategies will become increasingly more important. The following review provides a summary of the most recent information available.
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Affiliation(s)
- Massimiliano Sgroi
- Department of Civil Engineering and Architecture, University of Catania, Viale A. Doria 6, 95125, Catania, Italy.
| | - Federico G A Vagliasindi
- Department of Civil Engineering and Architecture, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
| | - Shane A Snyder
- Department of Chemical & Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ, 85721, USA; National University of Singapore, NUS Environmental Research Institute (NERI), 5A Engineering Drive 1; T-Lab Building, #02-01, 117411, Singapore
| | - Paolo Roccaro
- Department of Civil Engineering and Architecture, University of Catania, Viale A. Doria 6, 95125, Catania, Italy
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26
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Minakata D, Kamath D, Maetzold S. Mechanistic Insight into the Reactivity of Chlorine-Derived Radicals in the Aqueous-Phase UV-Chlorine Advanced Oxidation Process: Quantum Mechanical Calculations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:6918-6926. [PMID: 28541663 DOI: 10.1021/acs.est.7b00507] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The combined ultraviolet (UV) and free chlorine (UV-chlorine) advanced oxidation process that produces highly reactive hydroxyl radicals (HO•) and chlorine radicals (Cl•) is an attractive alternative to UV alone or chlorination for disinfection because of the destruction of a wide variety of organic compounds. However, concerns about the potential formation of chlorinated transformation products require an understanding of the radical-induced elementary reaction mechanisms and their reaction-rate constants. While many studies have revealed the reactivity of oxygenated radicals, the reaction mechanisms of chlorine-derived radicals have not been elucidated due to the data scarcity and discrepancies among experimental observations. We found a linear free-energy relationship quantum mechanically calculated free energies of reaction and the literature-reported experimentally measured reaction rate constants, kexp, for 22 chlorine-derived inorganic radical reactions in the UV-chlorine process. This relationship highlights the discrepancy among literature-reported rate constants and aids in the determination of the rate constant using quantum mechanical calculations. We also found linear correlations between the theoretically calculated free energies of activation and kexp for 31 reactions of Cl• with organic compounds. The correlation suggests that H-abstraction and Cl-adduct formation are the major reaction mechanisms. This is the first comprehensive study on chlorine-derived radical reactions, and it provides mechanistic insight into the reaction mechanisms for the development of an elementary reaction-based kinetic model.
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Affiliation(s)
- Daisuke Minakata
- Department of Civil and Environmental Engineering, Michigan Technological University , 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Divya Kamath
- Department of Civil and Environmental Engineering, Michigan Technological University , 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Shaye Maetzold
- Department of Civil and Environmental Engineering, Michigan Technological University , 1400 Townsend Drive, Houghton, Michigan 49931, United States
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27
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Pari S, Wang IA, Liu H, Wong BM. Sulfate radical oxidation of aromatic contaminants: a detailed assessment of density functional theory and high-level quantum chemical methods. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:395-404. [PMID: 28229155 DOI: 10.1039/c7em00009j] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Advanced oxidation processes that utilize highly oxidative radicals are widely used in water reuse treatment. In recent years, the application of sulfate radical (SO4˙-) as a promising oxidant for water treatment has gained increasing attention. To understand the efficiency of SO4˙- in the degradation of organic contaminants in wastewater effluent, it is important to be able to predict the reaction kinetics of various SO4˙--driven oxidation reactions. In this study, we utilize density functional theory (DFT) and high-level wavefunction-based methods (including computationally-intensive coupled cluster methods), to explore the activation energies of SO4˙--driven oxidation reactions on a series of benzene-derived contaminants. These high-level calculations encompass a wide set of reactions including 110 forward/reverse reactions and 5 different computational methods in total. Based on the high-level coupled-cluster quantum calculations, we find that the popular M06-2X DFT functional is significantly more accurate for OH- additions than for SO4˙- reactions. Most importantly, we highlight some of the limitations and deficiencies of other computational methods, and we recommend the use of high-level quantum calculations to spot-check environmental chemistry reactions that may lie outside the training set of the M06-2X functional, particularly for water oxidation reactions that involve SO4˙- and other inorganic species.
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Affiliation(s)
- Sangavi Pari
- Department of Chemical & Environmental Engineering, University of California-Riverside, Riverside, California, USA.
| | - Inger A Wang
- Department of Chemical & Environmental Engineering, University of California-Riverside, Riverside, California, USA.
| | - Haizhou Liu
- Department of Chemical & Environmental Engineering, University of California-Riverside, Riverside, California, USA.
| | - Bryan M Wong
- Department of Chemical & Environmental Engineering, University of California-Riverside, Riverside, California, USA. and Materials Science & Engineering Program, University of California-Riverside, Riverside, California, USA.
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28
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Yu H, Ge P, Chen J, Xie H, Luo Y. The degradation mechanism of sulfamethoxazole under ozonation: a DFT study. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:379-387. [PMID: 28165516 DOI: 10.1039/c6em00698a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sulfamethoxazole (SMX), a kind of antibiotic, remains in the environment and threatens public health. Ozone as a strong and green oxidant was widely used for selective oxidation degradation of residual SMX. However, it is hard to elucidate the detailed oxidation mechanism through current experimental approaches. A theoretical study has been carried out herein for exploring possible ozonation pathways of SMX. Two reaction mechanisms, viz., direct addition (DA) and H atom transfer (HAT), are considered. The results show that the primary oxidation of aromatic rings (benzene or isoxazole rings) of SMX follows the DA mechanism, featuring an electrophilic addition. Whereas, the oxidation of amino and methyl groups of SMX follows the HAT mechanism. Following the proposed mechanisms, the primary oxidation products detected in previous experiments could reasonably be obtained according to the current calculations. More importantly, O3 molecules as an electrophilic agent feasibly attack the moiety having a large orbital contribution to the highest occupied molecular orbital (HOMO) of sulfonamides. This result suggests that the primary ozonation site of sulfonamides could be theoretically predictable through the information of their frontier molecular orbitals. Meanwhile, a positive correlation between the O3-mediated HAT energy barriers and bond dissociation energies has been found for N-H and C-H bond oxidations.
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Affiliation(s)
- Hang Yu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
| | - Pu Ge
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Hongbin Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yi Luo
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
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29
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Heeb MB, Kristiana I, Trogolo D, Arey JS, von Gunten U. Formation and reactivity of inorganic and organic chloramines and bromamines during oxidative water treatment. WATER RESEARCH 2017; 110:91-101. [PMID: 27998787 DOI: 10.1016/j.watres.2016.11.065] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 11/26/2016] [Accepted: 11/29/2016] [Indexed: 06/06/2023]
Abstract
The formation and further reactions of halamines during oxidative water treatment can be relevant for water quality. In this study, we investigated the formation and reactivity of several inorganic and organic halamines (monochloramine, N-chloromethylamine, N-chlorodimethylamine, monobromamine, dibromamine, N-bromomethylamine, N,N-dibromomethylamine, and N-bromodimethylamine) by kinetic experiments, transformation product analysis, and quantum chemical computations. Kinetic model simulations were conducted to evaluate the relevance of halamines for various water treatment scenarios. Halamines were quickly formed from the reaction of chlorine and bromine with ammonia or organic amines. Species-specific second-order rate constants for the reaction of chlorine and bromine with ammonia, methyl- and dimethylamine were in the order of 106-108 M-1s-1. The formed halamines were found to be reactive towards phenolic compounds, forming halogenated phenols via electrophilic aromatic substitution (phenol and resorcinol) or quinones via electron transfer (catechol and hydroquinone). At near neutral pH, apparent second-order rate constants for these reactions were in the order of 10-4-10-1 M-1s-1 for chloramines and 101-102 M-1s-1 for bromamines. Quantum chemical computations were used to determine previously unknown aqueous pKa values, gas phase bond dissociation energies (BDE) and partial atomic charges of the halamines, allowing a better understanding of their reactivities. Kinetic model simulations, based on the results of this study, showed that during chlorination inorganic and organic chloramines are the main halamines formed. However, their further reactions with organic matter are outcompeted kinetically by chlorine. During ozonation, mainly inorganic bromamines are formed, since ozone quickly oxidizes organic amines. The further reactions of bromamine are typically outcompeted by ozone and thus generally of minor importance. The use of peracetic acid for saline ballast water treatment can result in the formation of substantial amounts of bromamines, which can react with dissolved organic matter and contribute to the formation of brominated products.
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Affiliation(s)
- Michèle B Heeb
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Ina Kristiana
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Curtin Water Quality Research Centre, Curtin University, Perth, Western Australia, Australia
| | - Daniela Trogolo
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - J Samuel Arey
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Urs von Gunten
- School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland.
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30
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Liu YD, Zhong R. Comparison of N-nitrosodimethylamine formation mechanisms from dimethylamine during chloramination and ozonation: A computational study. JOURNAL OF HAZARDOUS MATERIALS 2017; 321:362-370. [PMID: 27643481 DOI: 10.1016/j.jhazmat.2016.09.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/27/2016] [Accepted: 09/11/2016] [Indexed: 06/06/2023]
Abstract
N-nitrosodimethylamine (NDMA) as a disinfection by-product has recently become the focus of considerable research interest due to its unusually high carcinogenicity. In this study, the formation mechanisms of NDMA from dimethylamine (DMA) during chloramination and ozonation were investigated by using the quantum chemical G4 method. The reactivity of haloamines and hydroxylamine reacting with DMA was found in the order: NHCl2∼NHBrCl (Br-leaving)>NHBr2>NH2Cl∼NH2Br>>NH2OH. This offers a theoretical support for the experimentally proposed mechanism that dimethylamine reacts with NHCl2 rather than NH2Cl to form chlorinated unsymmetrical dimethylhydrazine intermediate and the existence of bromochloramine in the presence of bromide during chloramination, and explains the observation that NDMA yield during ozonation is much lower than that during chloramination. Importantly, an N,N-dimethylaminonitrene was found to be a significant intermediate to form NDMA in oxidation reactions by molecular oxygen and ozone. Additionally, results suggest that the amines containing the second nitrogen source directly connecting or close to the N-(CH3)2 moiety are potential significant NDMA precursors upon ozonation. The findings of this study are helpful for expanding the knowledge of NDMA formation mechanism, and predicting potential NDMA precursors during disinfection.
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Affiliation(s)
- Yong Dong Liu
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China.
| | - Rugang Zhong
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, China
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31
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Trogolo D, Arey JS. Equilibria and Speciation of Chloramines, Bromamines, and Bromochloramines in Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:128-140. [PMID: 27983824 DOI: 10.1021/acs.est.6b03219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The stabilities and speciation of the halamines in water are difficult to characterize experimentally. We provide theoretical estimates of aqueous standard free energies of formation for inorganic chloramines, bromamines, and bromochloramines, based on high-accuracy theoretical standard free energies of formation in gas phase combined with quantum chemical estimates of Henry's law constant. Based on comparisons between several theoretical and experimental datasets, we assign an error of 1.1-1.2 log unit for equilibrium constants of several reactions leading to halamines in water. The reactions of ammonia with HOCl or HOBr that lead to dichloramine, trichloramine, and tribromamine are found to be thermodynamically more favorable than was previously believed. The newly reported equilibrium data also allow us to propose rate constant values for some hydrolysis and disproportionation reactions of dichloramine, monobromamine, and bromochloramine. Finally, theoretical results indicate aqueous acid dissociation constant (pKa) values of 1.5 ± 1 for NH3Cl+, 0.8 ± 1 for NH3Br+, 11.8 ± 1 for NHCl2, and 12.5 ± 1 for NHBrCl. The present report provides a comprehensive data set describing the free energies of the neutral inorganic halamines, the anionic conjugate base species, and the cationic conjugate acid species, with approximately uniform uncertainty bounds assigned throughout.
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Affiliation(s)
- Daniela Trogolo
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - J Samuel Arey
- École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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32
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Lim S, Lee W, Na S, Shin J, Lee Y. N-nitrosodimethylamine (NDMA) formation during ozonation of N,N-dimethylhydrazine compounds: Reaction kinetics, mechanisms, and implications for NDMA formation control. WATER RESEARCH 2016; 105:119-128. [PMID: 27611639 DOI: 10.1016/j.watres.2016.08.054] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/22/2016] [Accepted: 08/26/2016] [Indexed: 05/17/2023]
Abstract
Compounds with N,N-dimethylhydrazine moieties ((CH3)2N-N-) form N-nitrosodimethylamine (NDMA) during ozonation, but the relevant reaction chemistry is hitherto poorly understood. This study investigated the reaction kinetics and mechanisms of NDMA formation during ozonation of unsymmetrical dimethylhydrazine (UDMH) and daminozide (DMZ) as structural model N,N-dimethylhydrazine compounds. The reaction of ozone with these NDMA precursor compounds was fast, and kO3 at pH 7 was 2 × 106 M-1 s-1 for UDMH and 5 × 105 M-1 s-1 for DMZ. Molar NDMA yields (i.e., Δ[NDMA]/Δ[precursor] × 100) were 84% and 100% for UDMH and DMZ, respectively, determined at molar ozone dose ratio ([O3]0/[precursor]0) of ≥4 in the presence of tert-butanol as hydroxyl radical (OH) scavenger. The molar NDMA yields decreased significantly in the absence of tert-butanol, indicating OH formation and its subsequent reaction with the parent precursors forming negligible NDMA. The kOH at pH 7 was 4.9 × 109 M-1 s-1 and 3.4 × 109 M-1 s-1 for UDMH and DMZ, respectively. Reaction mechanisms are proposed in which an ozone adduct is formed at the nitrogen next to N,N-dimethylamine which decomposes via homolytic and heterolytic cleavages of the -N+-O-O-O- bond, forming NDMA as a final product. The heterolytic cleavage pathway explains the significant OH formation via radical intermediates. Overall, significant NDMA formation was found to be unavoidable during ozonation or even O3/H2O2 treatment of waters containing N,N-dimethylhydrazine compounds due to their rapid reaction with ozone forming NDMA with high yield. Thus, source control or pre-treatment of N,N-dimethylhydrazine precursors and post-treatment of NDMA are proposed as the mitigation options.
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Affiliation(s)
- Sungeun Lim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Republic of Korea
| | - Woongbae Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Republic of Korea
| | - Soyoung Na
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Republic of Korea
| | - Jaedon Shin
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Republic of Korea
| | - Yunho Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 500-712, Republic of Korea.
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33
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Sviatenko LK, Gorb L, Hill FC, Leszczynska D, Shukla MK, Okovytyy SI, Hovorun D, Leszczynski J. In Silico Alkaline Hydrolysis of Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine: Density Functional Theory Investigation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10039-10046. [PMID: 27523798 DOI: 10.1021/acs.est.5b06130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), an energetic material used in military applications, may be released to the environment during manufacturing, transportation, storage, training, and disposal. A detailed investigation of a possible mechanism of alkaline hydrolysis, as one of the most promising methods for HMX remediation, was performed by computational study at PCM(Pauling)/M06-2X/6-311++G(d,p) level. Obtained results suggest that HMX hydrolysis at pH 10 represents a highly exothermic multistep process involving initial deprotonation and nitrite elimination, hydroxide attachment accompanied by cycle cleavage, and further decomposition of cycle-opened intermediate to the products caused by a series of C-N bond ruptures, hydroxide attachments, and proton transfers. Computationally predicted products of HMX hydrolysis such as nitrite, 4-nitro-2,4-diazabutanal, formaldehyde, nitrous oxide, formate, and ammonia correspond to experimentally observed species. Based on computed reaction pathways for HMX decomposition by alkaline hydrolysis, the kinetics of the entire process was modeled. Very low efficiency of this reaction at pH 10 was observed. Computations predict significant increases (orders of magnitude) of the hydrolysis rate for hydrolysis reactions undertaken at pH 11, 12, and 13.
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Affiliation(s)
- Liudmyla K Sviatenko
- Department of Organic Chemistry, Oles Honchar Dnipropetrovsk National University , Dnipropetrovsk 49000, Ukraine
| | - Leonid Gorb
- HX5 , Vicksburg, Mississippi 39180, United States
| | - Frances C Hill
- U.S. Army Engineer Research and Development Center , Vicksburg, Mississippi 39180, United States
| | | | - Manoj K Shukla
- U.S. Army Engineer Research and Development Center , Vicksburg, Mississippi 39180, United States
| | - Sergiy I Okovytyy
- Department of Organic Chemistry, Oles Honchar Dnipropetrovsk National University , Dnipropetrovsk 49000, Ukraine
| | - Dmytro Hovorun
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine , 150 Zabolotny Street, Kyiv 03143, Ukraine
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34
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Trerayapiwat K, Ricke N, Cohen P, Poblete A, Rudel H, Eustis SN. Sticking to (first) principles: quantum molecular dynamics and Bayesian probabilistic methods to simulate aquatic pollutant absorption spectra. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:1068-1077. [PMID: 27378210 DOI: 10.1039/c6em00233a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work explores the relationship between theoretically predicted excitation energies and experimental molar absorption spectra as they pertain to environmental aquatic photochemistry. An overview of pertinent Quantum Chemical descriptions of sunlight-driven electronic transitions in organic pollutants is presented. Second, a combined molecular dynamics (MD), time-dependent density functional theory (TD-DFT) analysis of the ultraviolet to visible (UV-Vis) absorption spectra of six model organic compounds is presented alongside accurate experimental data. The functional relationship between the experimentally observed molar absorption spectrum and the discrete quantum transitions is examined. A rigorous comparison of the accuracy of the theoretical transition energies (ΔES0→Sn) and oscillator strength (fS0→Sn) is afforded by the probabilistic convolution and deconvolution procedure described. This method of deconvolution of experimental spectra using a Gaussian Mixture Model combined with Bayesian Information Criteria (BIC) to determine the mean (μ) and standard deviation (σ) as well as the number of observed singlet to singlet transition energy state distributions. This procedure allows a direct comparison of the one-electron (quantum) transitions that are the result of quantum chemical calculations and the ensemble of non-adiabatic quantum states that produce the macroscopic effect of a molar absorption spectrum. Poor agreement between the vertical excitation energies produced from TD-DFT calculations with five different functionals (CAM-B3LYP, PBE0, M06-2X, BP86, and LC-BLYP) suggest a failure of the theory to capture the low energy, environmentally important, electronic transitions in our model organic pollutants. However, the method of explicit-solvation of the organic solute using the quantum Effective Fragment Potential (EFP) in a density functional molecular dynamics trajectory simulation shows promise as a robust model of the hydrated organic pollutant. Furthermore, the described protocol can be extended using higher-level equilibration and vertical excitation methods to increase the numerical accuracy and describe multi-reference electronic transitions. Finally, a measure of the accuracy of theoretically derived absorption spectra is discussed as a tool to further develop our capacity to produce accurate a priori simulations of sunlight-driven photochemistry in natural waters.
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Affiliation(s)
- Kasidet Trerayapiwat
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
| | - Nathan Ricke
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
| | - Peter Cohen
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
| | - Alex Poblete
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
| | - Holly Rudel
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
| | - Soren N Eustis
- Department of Chemistry, Bowdoin College, 6600 College Station, Brunswick, ME, USA.
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35
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Zhang O, Zou X, Li QH, Sun Z, Liu YD, Zhong RG. Experimental and Theoretical Investigation of Effects of Ethanol and Acetic Acid on Carcinogenic NDMA Formation in Simulated Gastric Fluid. J Phys Chem A 2016; 120:4505-13. [DOI: 10.1021/acs.jpca.6b02582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ou Zhang
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
| | - Xuan Zou
- Department
of Stomatology, Chinese PLA 307 Hospital, Academy of Military Medical Sciences, Beijing, 100071, P. R. China
| | - Qi-Hong Li
- Department
of Stomatology, Chinese PLA 307 Hospital, Academy of Military Medical Sciences, Beijing, 100071, P. R. China
| | - Zhi Sun
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
| | - Yong Dong Liu
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
| | - Ru Gang Zhong
- College of Life Science & Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
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36
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Liu Y, Liu Y, Zhong R, Peng B, Schaefer, III HF. Effects of heavy metal ions on N-nitrosodimethylamine (NDMA) formation. RSC Adv 2016. [DOI: 10.1039/c6ra11481d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mechanism of NDMA formation as affected by heavy metal complexes [MONO]+ (M = Cd, Pb, Hg) was investigated using density functional theory (DFT). Three possible NDMA formation pathways are discussed.
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Affiliation(s)
- Yameng Liu
- Beijing Key Laboratory of Environmental and Viral Oncology
- College of Life Science & Bioengineering
- Beijing University of Technology
- Beijing 100124
- P. R. China
| | - Yongdong Liu
- Beijing Key Laboratory of Environmental and Viral Oncology
- College of Life Science & Bioengineering
- Beijing University of Technology
- Beijing 100124
- P. R. China
| | - Rugang Zhong
- Beijing Key Laboratory of Environmental and Viral Oncology
- College of Life Science & Bioengineering
- Beijing University of Technology
- Beijing 100124
- P. R. China
| | - Bin Peng
- Center for Computational Quantum Chemistry
- MOE Key Laboratory of Theoretical Chemistry of the Environment
- South China Normal University
- Guangzhou
- P. R. China
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