1
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Buckley S, McKay G, Leresche F, Rosario-Ortiz F. Inferring the Molecular Basis for Dissolved Organic Matter Photochemical and Optical Properties. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:9040-9050. [PMID: 38743693 DOI: 10.1021/acs.est.3c10881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Despite the widespread use of photochemical and optical properties to characterize dissolved organic matter (DOM), a significant gap persists in our understanding of the relationship among these properties. This study infers the molecular basis for the optical and photochemical properties of DOM using a comprehensive framework and known structural moieties within DOM. Utilizing Suwannee River Fulvic Acid (SRFA) as a model DOM, carboxylated aromatics, phenols, and quinones were identified as dominant contributors to the absorbance spectra, and phenols, quinones, aldehydes, and ketones were identified as major contributors to radiative energy pathways. It was estimated that chromophores constitute ∼63% w/w of dissolved organic carbon in SRFA and ∼47% w/w of overall SRFA. Notably, estimations indicate the pool of fluorescent compounds and photosensitizing compounds in SRFA are likely distinct from each other at wavelengths below 400 nm. This perspective offers a practical tool to aid in the identification of probable chemical groups when interpreting optical and photochemical data and challenges the current "black box" thinking. Instead, DOM photochemical and optical properties can be closely estimated by assuming the DOM is composed of a mixture of individual compounds.
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Affiliation(s)
- Shelby Buckley
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Garrett McKay
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, Texas 77845, United States
| | - Frank Leresche
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Fernando Rosario-Ortiz
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
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2
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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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3
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Yin R, Heuzard A, Li T, Ruan X, Lu S, Shang C. Advanced oxidation of recalcitrant chromophores in full-scale MBR effluent for non-potable reuse of leachate co-treated municipal wastewater. CHEMOSPHERE 2024; 351:141228. [PMID: 38237782 DOI: 10.1016/j.chemosphere.2024.141228] [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: 11/30/2023] [Revised: 01/08/2024] [Accepted: 01/13/2024] [Indexed: 01/22/2024]
Abstract
Wastewater non-potable reuse involves further processing of secondary effluent to a quality level acceptable for reuse and is a promising solution to combating water scarcity. Recalcitrant chromophores in landfill leachate challenge the water quality for non-potable reuse when leachate is co-treated with municipal wastewater. In this study, we first use multivariate statistical analysis to reveal that leachate is an important source (with a Pearson's coefficient of 0.82) of recalcitrant chromophores in the full-scale membrane bioreactor (MBR) effluent. We then evaluate the removal efficacies of chromophores by chlorination, breakpoint chlorination, and the chlorination-UV/chlorine advanced oxidation treatment. Conventional chlorination and breakpoint chlorination only partially remove chromophores, leaving a colour level exceeding the standards for non-potable reuse (>20 Hazen units). We demonstrate that pre-chlorination (with an initial chlorine dosing of 20 mg/L as Cl2) followed by UV radiation (with a UV fluence of 500 mJ/cm2) effectively degraded recalcitrant chromophores (>90%). By quantifying the electron donating capacity (EDC) and radical scavenging capacity (RSC) of the reclaimed water, we demonstrate that pre-chlorination reduces EDC and RSC by up to 64%, increases UV transmittance by 32%, and increases radical yields from UV photolysis of chlorine by 1.7-2.2 times. The findings advance fundamental understanding of the alteration of dissolved coloured substances by (photo)chlorination treatment and provide implications for applying advanced oxidation processes in treating wastewater effluents towards sustainable non-potable reuse.
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Affiliation(s)
- Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| | - Arnaud Heuzard
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Tao Li
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; China State Construction Engineering (Hong Kong) Limited, Wan Chai, Hong Kong
| | - Xinyi Ruan
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Senhao Lu
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Chii Shang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Hong Kong Branch of Chinese National Engineering Research Centre for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
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4
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Lim S, Barrios B, Minakata D, von Gunten U. Reactivity of Bromine Radical with Dissolved Organic Matter Moieties and Monochloramine: Effect on Bromate Formation during Ozonation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18658-18667. [PMID: 36706342 PMCID: PMC10690713 DOI: 10.1021/acs.est.2c07694] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/29/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
Bromine radical (Br•) has been hypothesized to be a key intermediate of bromate formation during ozonation. Once formed, Br• further reacts with ozone to eventually form bromate. However, this reaction competes with the reaction of Br• with dissolved organic matter (DOM), of which reactivity and reaction mechanisms are less studied to date. To fill this gap, this study determined the second-order rate constant (k) of the reactions of selected organic model compounds, a DOM isolate, and monochloramine (NH2Cl) with Br• using γ-radiolysis. The kBr• of all model compounds were high (kBr• > 108 M-1 s-1) and well correlated with quantum-chemically computed free energies of activation, indicating a selectivity of Br• toward electron-rich compounds, governed by electron transfer. The reaction of phenol (a representative DOM moiety) with Br• yielded p-benzoquinone as a major product with a yield of 59% per consumed phenol, suggesting an electron transfer mechanism. Finally, the potential of NH2Cl to quench Br• was tested based on the fast reaction (kBr•, NH2Cl = 4.4 × 109 M-1 s-1, this study), resulting in reduced bromate formation of up to 77% during ozonation of bromide-containing lake water. Overall, our study demonstrated that Br• quenching by NH2Cl can substantially suppress bromate formation, especially in waters containing low DOC concentrations (1-2 mgC/L).
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Affiliation(s)
- Sungeun Lim
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, Duebendorf 8600, Switzerland
| | - Benjamin Barrios
- Department
of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Daisuke Minakata
- Department
of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Urs von Gunten
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, Duebendorf 8600, Switzerland
- School
of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale
de Lausanne (EPFL), Lausanne 1015, Switzerland
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5
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Houska J, Stocco L, Hofstetter TB, Gunten UV. Hydrogen Peroxide Formation during Ozonation of Olefins and Phenol: Mechanistic Insights from Oxygen Isotope Signatures. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18950-18959. [PMID: 37155568 PMCID: PMC10690717 DOI: 10.1021/acs.est.3c00788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 05/10/2023]
Abstract
Mitigation of undesired byproducts from ozonation of dissolved organic matter (DOM) such as aldehydes and ketones is currently hampered by limited knowledge of their precursors and formation pathways. Here, the stable oxygen isotope composition of H2O2 formed simultaneously with these byproducts was studied to determine if it can reveal this missing information. A newly developed procedure, which quantitatively transforms H2O2 to O2 for subsequent 18O/16O ratio analysis, was used to determine the δ18O of H2O2 generated from ozonated model compounds (olefins and phenol, pH 3-8). A constant enrichment of 18O in H2O2 with a δ18O value of ∼59‰ implies that 16O-16O bonds are cleaved preferentially in the intermediate Criegee ozonide, which is commonly formed from olefins. H2O2 from the ozonation of acrylic acid and phenol at pH 7 resulted in lower 18O enrichment (δ18O = 47-49‰). For acrylic acid, enhancement of one of the two pathways followed by a carbonyl-H2O2 equilibrium was responsible for the smaller δ18O of H2O2. During phenol ozonation at pH 7, various competing reactions leading to H2O2 via an intermediate ozone adduct are hypothesized to cause lower δ18O in H2O2. These insights provide a first step toward supporting pH-dependent H2O2 precursor elucidation in DOM.
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Affiliation(s)
- Joanna Houska
- Eawag
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- School
of Architecture, Civil, and Environmental Engineering, École Polytechnique Fédérale
de Lausanne, 1015 Lausanne, Switzerland
| | - Laura Stocco
- Eawag
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- School
of Architecture, Civil, and Environmental Engineering, École Polytechnique Fédérale
de Lausanne, 1015 Lausanne, Switzerland
| | - Thomas B. Hofstetter
- Eawag
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Department
of Environmental System Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Urs von Gunten
- Eawag
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- School
of Architecture, Civil, and Environmental Engineering, École Polytechnique Fédérale
de Lausanne, 1015 Lausanne, Switzerland
- Department
of Environmental System Science, ETH Zurich, 8092 Zurich, Switzerland
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6
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Morrison C, Hogard S, Pearce R, Mohan A, Pisarenko AN, Dickenson ERV, von Gunten U, Wert EC. Critical Review on Bromate Formation during Ozonation and Control Options for Its Minimization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18393-18409. [PMID: 37363871 PMCID: PMC10690720 DOI: 10.1021/acs.est.3c00538] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023]
Abstract
Ozone is a commonly applied disinfectant and oxidant in drinking water and has more recently been implemented for enhanced municipal wastewater treatment for potable reuse and ecosystem protection. One drawback is the potential formation of bromate, a possible human carcinogen with a strict drinking water standard of 10 μg/L. The formation of bromate from bromide during ozonation is complex and involves reactions with both ozone and secondary oxidants formed from ozone decomposition, i.e., hydroxyl radical. The underlying mechanism has been elucidated over the past several decades, and the extent of many parallel reactions occurring with either ozone or hydroxyl radicals depends strongly on the concentration, type of dissolved organic matter (DOM), and carbonate. On the basis of mechanistic considerations, several approaches minimizing bromate formation during ozonation can be applied. Removal of bromate after ozonation is less feasible. We recommend that bromate control strategies be prioritized in the following order: (1) control bromide discharge at the source and ensure optimal ozone mass-transfer design to minimize bromate formation, (2) minimize bromate formation during ozonation by chemical control strategies, such as ammonium with or without chlorine addition or hydrogen peroxide addition, which interfere with specific bromate formation steps and/or mask bromide, (3) implement a pretreatment strategy to reduce bromide and/or DOM prior to ozonation, and (4) assess the suitability of ozonation altogether or utilize a downstream treatment process that may already be in place, such as reverse osmosis, for post-ozone bromate abatement. A one-size-fits-all approach to bromate control does not exist, and treatment objectives, such as disinfection and micropollutant abatement, must also be considered.
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Affiliation(s)
- Christina
M. Morrison
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Samantha Hogard
- Hampton
Roads Sanitation District, P.O. Box 5911, Virginia Beach, Virginia 23471-0911, United
States
- The
Charles Edward Via, Jr. Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Robert Pearce
- Hampton
Roads Sanitation District, P.O. Box 5911, Virginia Beach, Virginia 23471-0911, United
States
- The
Charles Edward Via, Jr. Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Aarthi Mohan
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Aleksey N. Pisarenko
- Trussell
Technologies, Inc., 380
Stevens Avenue, Suite 212, Solana Beach, California 92075, United States
| | - Eric R. V. Dickenson
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
| | - Urs von Gunten
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, CH-8600 Dubendorf, Switzerland
- School of
Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne
(EPFL), 1015 Lausanne, Switzerland
| | - Eric C. Wert
- Southern
Nevada Water Authority (SNWA), P.O. Box 99954, Las Vegas, Nevada 89193-9954, United
States
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7
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Mensah AT, Xiang Y, Berne F, Soreau S, Gallard H. Reactions of Monobromamine and Dibromamine with Phenolic Compounds and Organic Matter: Kinetics and Formation of Bromophenols and Bromoform. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18981-18990. [PMID: 37226837 DOI: 10.1021/acs.est.3c00935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Monobromamine (NH2Br) and dibromamine (NHBr2) produced from reactions of hypobromous acid (HOBr) with ammonia can react with phenolic structures of natural organic matter (NOM) to produce disinfection byproducts such as bromoform (CHBr3). The reactivity of NH2Br was controlled by the reaction of the bromoammonium ion (NH3Br+) with phenolate species, with specific rate constants ranging from 6.32 × 102 for 2,4,6-tribromophenol to 1.22 × 108 M-1 s-1 for phenol. Reactions of NHBr2 with phenol and bromophenols were negligible compared to its self-decomposition; rate constants could be determined only with resorcinol for pH > 7. At pH 8.1-8.2, no formation of CHBr3 was observed from the reaction of NH2Br with phenol while the reaction of NH2Br with resorcinol produced a significant concentration of CHBr3. In contrast to NH2Br, a significant amount of CHBr3 produced with an excess of NHBr2 over phenol was explained by the reactions of HOBr produced from NHBr2 decomposition. A comprehensive kinetic model including the formation and decomposition of bromamines and the reactivity of HOBr and NH2Br with phenolic compounds was developed at pH 8.0-8.3. Furthermore, the kinetic model was used to evaluate the significance of the NH2Br and NHBr2 reactions with the phenolic structures of two NOM isolates.
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Affiliation(s)
- Anette T Mensah
- Institut de Chimie des Milieux et des Matériaux de Poitiers IC2MP UMR 7285 CNRS Université de Poitiers, ENSI Poitiers, 1 rue Marcel Doré TSA 41105, 86 073 Cedex 9, Poitiers, France
| | - Yingying Xiang
- Institut de Chimie des Milieux et des Matériaux de Poitiers IC2MP UMR 7285 CNRS Université de Poitiers, ENSI Poitiers, 1 rue Marcel Doré TSA 41105, 86 073 Cedex 9, Poitiers, France
| | - Florence Berne
- Institut de Chimie des Milieux et des Matériaux de Poitiers IC2MP UMR 7285 CNRS Université de Poitiers, ENSI Poitiers, 1 rue Marcel Doré TSA 41105, 86 073 Cedex 9, Poitiers, France
| | - Sylvie Soreau
- EDF - Recherche et Développement, Laboratoire National d'Hydraulique et Environnement (LNHE), 6 quai Watier, 78401 Chatou Cedex, France
| | - Hervé Gallard
- Institut de Chimie des Milieux et des Matériaux de Poitiers IC2MP UMR 7285 CNRS Université de Poitiers, ENSI Poitiers, 1 rue Marcel Doré TSA 41105, 86 073 Cedex 9, Poitiers, France
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8
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Yang P, Jiang T, Cao D, Sun T, Liu G, Guo Y, Liu Y, Yin Y, Cai Y, Jiang G. Unraveling Multiple Pathways of Electron Donation from Phenolic Moieties in Natural Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16895-16905. [PMID: 37870506 DOI: 10.1021/acs.est.3c05377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Natural organic matter (NOM) exhibits a distinctive electron-donating capacity (EDC) that serves a pivotal role in the redox reactions of contaminants and minerals through the transformation of electron-donating phenolic moieties. However, the ambiguity of the molecular transformation pathways (MTPs) that engender the EDC during NOM oxidation remains a significant issue. Here, MTPs that contribute to EDC were investigated by identifying the oxidized products of phenolic model compounds and NOM samples in direct or mediated electrochemical oxidation (DEO or MEO, respectively) using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). It was found that the oxidation of newly formed phenolic-OH (ArOH) and the oxidative coupling reaction of the phenoxy radical are the main MTPs that directly contribute to EDC, in addition to the transformation of hydroquinones to quinones. Notably, the oxidative coupling reaction of ArOH contributed at least 22-42% to the EDC. Ferulic acid-like structures can also directly contribute to EDC by incorporating H2O into their acrylic substituents. Furthermore, the opening of C rings can indirectly attenuate the EDC through structural alterations in the electron-donating process of NOM. Decarboxylation can either weaken or enhance the EDC depending on the structure of the phenolic moieties in NOM. These findings suggest that the EDC of NOM is a comprehensive result of multiple NOM MTPs, involving not only ArOH oxidation but also the addition of H2O to olefinic bonds and bond-breaking reactions. Our work provides molecular evidence that aids in the comprehension of the multiple EDC-associated transformation pathways of NOM.
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Affiliation(s)
- Peijie Yang
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Jiang
- Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400716, China
| | - Dong Cao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianran Sun
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Yingying Guo
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yanwei Liu
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Yong Cai
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Guo Y, Yu G, von Gunten U, Wang Y. Evaluation of the role of superoxide radical as chain carrier for the formation of hydroxyl radical during ozonation. WATER RESEARCH 2023; 242:120158. [PMID: 37329717 DOI: 10.1016/j.watres.2023.120158] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/26/2023] [Accepted: 05/30/2023] [Indexed: 06/19/2023]
Abstract
Superoxide radicals (O2•-) have been suggested as an important chain carrier in the radical chain reaction that promotes ozone (O3) decomposition to hydroxyl radicals (•OH) during ozonation. However, due to the difficulty in measuring transient O2•- concentrations, this hypothesis has not been verified under realistic ozonation conditions during water treatment. In this study, a probe compound was used in combination with kinetic modeling to evaluate the role of O2•- for O3 decomposition during ozonation of synthetic solutions with model promotors and inhibitors (methanol and acetate or tert-butanol) and natural waters (one groundwater and two surface waters). By measurement of the abatement of spiked tetrachloromethane (as a O2•- probe), the O2•- exposure during ozonation was determined. Based on the measured O2•- exposures, the relative contribution of O2•- to O3 decomposition, in comparison to OH-, •OH, and dissolved organic matter (DOM), was quantitatively evaluated using kinetic modeling. The results show that water compositions (e.g., the concentration of promotors and inhibitors, and the O3 reactivity of DOM) have a considerable effect on the extent of the O2•--promoted radical chain reaction during ozonation. In general, the reaction with O2•- accounted for ∼59‒70% and ∼45‒52% of the overall O3 decomposition during ozonation of the selected synthetic solutions and natural waters, respectively. This confirms that O2•- plays a critical role in promoting O3 decomposition to •OH. Overall, this study provides new insights on the controlling factors for ozone stability during ozonation processes.
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Affiliation(s)
- Yang Guo
- School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084 China
| | - Gang Yu
- School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084 China
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Yujue Wang
- School of Environment, Beijing Key Laboratory for Emerging Organic Contaminants Control, State Key Joint Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084 China.
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10
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Houska J, Manasfi T, Gebhardt I, von Gunten U. Ozonation of lake water and wastewater: Identification of carbonous and nitrogenous carbonyl-containing oxidation byproducts by non-target screening. WATER RESEARCH 2023; 232:119484. [PMID: 36746701 DOI: 10.1016/j.watres.2022.119484] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/27/2022] [Accepted: 12/09/2022] [Indexed: 06/18/2023]
Abstract
Ozonation of drinking water and wastewater is accompanied by the formation of disinfection byproducts (DBPs) such as low molecular weight aldehydes and ketones from the reactions of ozone with dissolved organic matter (DOM). By applying a recently developed non-target workflow, 178 carbonous and nitrogenous carbonyl compounds were detected during bench-scale ozonation of two lake waters and three secondary wastewater effluent samples and full-scale ozonation of secondary treated wastewater effluent. An overlapping subset of carbonyl compounds (20%) was detected in all water types. Moreover, wastewater effluents showed a significantly higher fraction of N-containing carbonyl compounds (30%) compared to lake water (17%). All carbonyl compounds can be classified in 5 main formation trends as a function of increasing specific ozone doses. Formation trends upon ozonation and comparison of results in presence and absence of the •OH radical scavenger DMSO in combination with kinetic and mechanistic information allowed to elucidate potential carbonyl structures. A link between the detected carbonyl compounds and their precursors was established by ozonating six model compounds (phenol, 4-ethylphenol, 4-methoxyphenol, sorbic acid, 3-buten-2-ol and acetylacetone). About one third of the detected carbonous carbonyl compounds detected in real waters was also detected by ozonating model compounds. Evaluation of the non-target analysis data revealed the identity of 15 carbonyl compounds, including hydroxylated aldehydes and ketones (e.g. hydroxyacetone, confidence level (CL) = 1), unsaturated dicarbonyls (e.g. acrolein, CL = 1; 2-butene-1,4-dial, CL = 1; 4-oxobut-2-enoic acid, CL = 2) and also a nitrogen-containing carbonyl compound (2-oxo-propanamide, CL =1). Overall, this study shows the formation of versatile carbonous and nitrogenous carbonyl compounds upon ozonation involving ozone and •OH reactions. Carbonyl compounds with unknown toxicity might be formed, and it could be demonstrated that acrolein, malondialdehyde, methyl glyoxal, 2-butene-1,4-dial and 4-oxo-pentenal are degraded during biological post-treatment.
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Affiliation(s)
- Joanna Houska
- Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Tarek Manasfi
- Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Switzerland
| | - Isabelle Gebhardt
- Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Switzerland
| | - Urs von Gunten
- Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich 8092, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
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11
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Manasfi T, Houska J, Gebhardt I, von Gunten U. Formation of carbonyl compounds during ozonation of lake water and wastewater: Development of a non-target screening method and quantification of target compounds. WATER RESEARCH 2023; 237:119751. [PMID: 37141690 DOI: 10.1016/j.watres.2023.119751] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/24/2023] [Accepted: 02/14/2023] [Indexed: 05/06/2023]
Abstract
Ozonation of natural waters is typically associated with the formation of carbonyl compounds (aldehydes, ketones and ketoacids), a main class of organic disinfection byproducts (DBPs). However, the detection of carbonyl compounds in water and wastewater is challenged by multiple difficulties inherent to their physicochemical properties. A non-target screening method involving the derivatisation of carbonyl compounds with p-toluenesulfonylhydrazine (TSH) followed by their analysis using liquid chromatography coupled to electrospray ionisation high-resolution mass spectrometry (LC-ESI-HRMS) and an advanced non-target screening and data processing workflow was developed. The workflow was applied to investigate the formation of carbonyl compounds during ozonation of different water types including lake water, aqueous solutions containing Suwannee River Fulvic acid (SRFA), and wastewater. A higher sensitivity for most target carbonyl compounds was achieved compared to previous derivatisation methods. Moreover, the method allowed the identification of known and unknown carbonyl compounds. 8 out of 17 target carbonyl compounds were consistently detected above limits of quantification (LOQs) in most ozonated samples. Generally, the concentrations of the 8 detected target compounds decreased in the order: formaldehyde > acetaldehyde > glyoxylic acid > pyruvic acid > glutaraldehyde > 2,3-butanedione > glyoxal > 1-acetyl-1-cyclohexene. The DOC concentration-normalised formation of carbonyl compounds during ozonation was higher in wastewater and SRFA-containing water than in lake water. The specific ozone doses and the type of the dissolved organic matter (DOM) played a predominant role for the extent of formation of carbonyl compounds. Five formation trends were distinguished for different carbonyl compounds. Some compounds were produced continuously upon ozonation even at high ozone doses, while others reached a maximum concentration at a certain ozone dose above which they decreased. Concentrations of target and peak areas of non-target carbonyl compounds during full-scale ozonation at a wastewater treatment plant showed an increase as a function of the specific ozone dose (sum of 8 target compounds ∼ 280 µg/L at 1 mgO3/mgC), followed by a significant decrease after biological sand filtration (> 64-94% abatement for the different compounds). This highlights the biodegradability of target and non-target carbonyl compounds and the importance of biological post-treatment.
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Affiliation(s)
- Tarek Manasfi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Joanna Houska
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Isabelle Gebhardt
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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12
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Li J, Zhang Z, Xiang Y, Jiang J, Yin R. Role of UV-based advanced oxidation processes on NOM alteration and DBP formation in drinking water treatment: A state-of-the-art review. CHEMOSPHERE 2023; 311:136870. [PMID: 36252895 DOI: 10.1016/j.chemosphere.2022.136870] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Oxidative treatment of drinking water has been practiced for more than a century. UV-based advanced oxidation processes (UV-AOPs) have emerged as promising oxidative treatment technologies to eliminate recalcitrant chemicals and biological contaminants in drinking water. UV-AOPs inevitably alter the properties of natural organic matter (NOM) and affect the disinfection byproduct (DBP) formation in the post-disinfection. This paper provides a state-of-the-art review on the effects of UV-AOPs on the changes of NOM properties and the consequent impacts on DBP formation in the post-chlorination process. A tutorial review to the connotations of NOM properties (e.g., bulk properties, fractional constituents, and molecular structures) and the associated state-of-the-art analytical methods are firstly presented. The impacts of different radical-based AOPs on the changes of NOM properties together with the underlying NOM-radical reaction mechanisms are discussed. The impacts of alteration of NOM properties on DBP formation in the post-chlorination process are then reviewed. The current knowledge gaps and future research needs are finally presented, with emphases on the needs to strengthen the comparability of research data in literature, the accuracy in quantifying the reactive moieties of NOM, and the awareness of unknown DBPs in oxidative water treatment processes. The review and discussion improve the fundamental understanding of NOM-radical and NOM-chlorine chemistry. They also provide useful implications on the engineering design and operation of next-generation drinking water treatment plants.
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Affiliation(s)
- Juan Li
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhu Hai 519087, PR China; Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR 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, PR China
| | - Yingying Xiang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR 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, PR China
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR China.
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13
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Wei S, Zhou C, Zhang G, Zheng H, Chen Z, Zhang S. Effects of a redox-active diketone on the photochemical transformation of roxarsone: Mechanisms and environmental implications. CHEMOSPHERE 2022; 308:136326. [PMID: 36084835 DOI: 10.1016/j.chemosphere.2022.136326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Organoarsenical antibiotics pose a severe threat to the environment and human health. In aquatic environment, dissolved organic matter (DOM)-mediated photochemical transformation is one of the main processes in the fate of organoarsenics. Dicarbonyl is a typical redox-active moiety in DOM. However, the knowledge on the photoconversion of organoarsenics by DOM, especially the contributions of dicarbonyl moieties is still limited. Here, we systematically investigated the photochemical transformation of three organoarsenics with the simplest β-diketone, acetylacetone (AcAc), as a model dicarbonyl moiety of DOM. The presence of AcAc significantly enhanced the photochemical conversion of roxarsone (ROX), whereas only minor effects were observed for 3-amino-4-hydroxyphenylarsonic acid (HAPA) and arsanilic acid (ASA), because the latter two (with an amino (-NH2) group) are more photoactive than ROX (with a nitro (-NO2) group). The results demonstrate that AcAc was a potent photo-activator and the reduction of -NO2 to -NH2 might be a rate-limiting step in the phototransformation of ROX. At a 1:1 M ratio of AcAc to ROX, the photochemical transformation rate of ROX was increased by 7 folds. In O2-rich environment, singlet oxygen, peroxide radicals, and ·OH were the main reactive species that led to the breakage of the C-As bond in ROX and the oxidation of the released arsono group to arsenate, whereas the triplet-excited state of AcAc (3AcAc*) and carbon-centered radicals from the photolysis of AcAc dominated in the reductive transformation of ROX. In anoxic environment, 3-amino-4-hydroxyphenylarsonic acid was one of the main reductive transformation intermediates of ROX, whose photolysis rate was about 35 times that of ROX. The knowledge obtained here is of great significance to better understand the fate of organoarsenics in natural environment.
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Affiliation(s)
- Shuangshuang Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Chang Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Hongcen Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
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14
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Wünsch R, Hettich T, Prahtel M, Thomann M, Wintgens T, von Gunten U. Tradeoff between micropollutant abatement and bromate formation during ozonation of concentrates from nanofiltration and reverse osmosis processes. WATER RESEARCH 2022; 221:118785. [PMID: 35949072 DOI: 10.1016/j.watres.2022.118785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/02/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Water treatment with nanofiltration (NF) or reverse osmosis (RO) membranes results in a purified permeate and a retentate, where solutes are concentrated and have to be properly managed and discharged. To date, little is known on how the selection of a semi-permeable dense membrane impacts the dissolved organic matter in the concentrate and what the consequences are for micropollutant (MP) abatement and bromate formation during concentrate treatment with ozone. Laboratory ozonation experiments were performed with standardized concentrates produced by three membranes (two NFs and one low-pressure reverse osmosis (LPRO) membrane) from three water sources (two river waters and one lake water). The concentrates were standardized by adjustment of pH and concentrations of dissolved organic carbon, total inorganic carbon, selected micropollutants (MP) with a low to high ozone reactivity and bromide to exclude factors which are known to impact ozonation. NF membranes had a lower retention of bromide and MPs than the LPRO membrane, and if the permeate quality of the NF membrane meets the requirements, the selection of this membrane type is beneficial due to the lower bromate formation risks upon concentrate ozonation. The bromate formation was typically higher in standardized concentrates of LPRO than of NF membranes, but the tradeoff between MP abatement and bromate formation upon ozonation of the standardized concentrates was not affected by the membrane type. Furthermore, there was no difference for the different source waters. Overall, ozonation of concentrates is only feasible for abatement of MPs with a high to moderate ozone reactivity with limited bromate formation. Differences in the DOM composition between NF and LPRO membrane concentrates are less relevant than retention of MPs and bromide by the membrane and the required ozone dose to meet a treatment target.
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Affiliation(s)
- R Wünsch
- FHNW University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Institute for Ecopreneurship, 4132 Muttenz, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - T Hettich
- FHNW University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Institute for Ecopreneurship, 4132 Muttenz, Switzerland
| | - M Prahtel
- FHNW University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Institute for Ecopreneurship, 4132 Muttenz, Switzerland; Chair of Urban Water Systems Engineering, Technical University of Munich, Garching, Germany
| | - M Thomann
- FHNW University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Institute for Ecopreneurship, 4132 Muttenz, Switzerland
| | - T Wintgens
- RWTH Aachen University, Institute of Environmental Engineering, 52074 Aachen, Germany
| | - U von Gunten
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
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15
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Rougé V, Lee Y, von Gunten U, Allard S. Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO 2 pre-oxidation for disinfection byproduct control. WATER RESEARCH 2022; 220:118515. [PMID: 35700645 DOI: 10.1016/j.watres.2022.118515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/13/2022] [Accepted: 04/25/2022] [Indexed: 06/15/2023]
Abstract
Chlorine dioxide (ClO2) applications to drinking water are limited by the formation of chlorite (ClO2-) which is regulated in many countries. However, when ClO2 is used as a pre-oxidant, ClO2- can be oxidized by chlorine during subsequent disinfection. In this study, a kinetic model for the reaction of chlorine with ClO2- was developed to predict the fate of ClO2- during chlorine disinfection. The reaction of ClO2- with chlorine was found to be highly pH-dependent with formation of ClO3- and ClO2 in ultrapure water. In presence of dissolved organic matter (DOM), 60-70% of the ClO2- was transformed to ClO3- during chlorination, while the in situ regenerated ClO2 was quickly consumed by reaction with DOM. The remaining 30-40% of the ClO2- first reacted to ClO2 which then formed chlorine from the DOM-ClO2 reaction. Since only part of the ClO2- was transformed to ClO3-, the sum of the molar concentrations of oxychlorine species (ClO2- + ClO3-) decreased during chlorination. By kinetic modelling, the ClO2- concentration after 24 h of chlorination was accurately predicted in synthetic waters but was largely overestimated in natural waters, possibly due to a ClO2- decay enhanced by high concentrations of chloride and in situ formed bromine from bromide. Understanding the chlorine-ClO2- reaction mechanism and the corresponding kinetics allows to potentially apply higher ClO2 doses during the pre-oxidation step, thus improving disinfection byproduct mitigation while keeping ClO2-, and if required, ClO3- below the regulatory limits. In addition, ClO2 was demonstrated to efficiently degrade haloacetonitrile precursors, either when used as pre-oxidant or when regenerated in situ during chlorination.
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Affiliation(s)
- Valentin Rougé
- Department of Chemistry, Curtin Water Quality Research Centre, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Yunho Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - 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 Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Sébastien Allard
- Department of Chemistry, Curtin Water Quality Research Centre, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia.
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16
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Xie M, Zhang C, Zheng H, Zhang G, Zhang S. Peroxyl radicals from diketones enhanced the indirect photochemical transformation of carbamazepine: Kinetics, mechanisms, and products. WATER RESEARCH 2022; 217:118424. [PMID: 35429883 DOI: 10.1016/j.watres.2022.118424] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/19/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
In surface waters, photogenerated transients (e.g., hydroxyl radicals, carbonate radicals, singlet oxygen and the triplet states of dissolved organic matter) are known to play a role in the transformation of biorecalcitrant carbamazepine (CBZ). Small diketones, such as acetylacetone (AcAc) and butanedione (BD), are naturally abundant and have been proven to be effective precursors of carbon and oxygen centered radicals. However, the photochemical kinetics and mechanisms of coexisting diketones and CBZ are barely known. Herein, the effects of AcAc and BD on the photochemical conversion of CBZ were investigated compared with H2O2 which was the main ·OH precursor in the environment. An enhancing effect was observed for the degradation of CBZ by the addition of diketones. The enhancing effect of diketones was pH-dependent and much more significant than H2O2 under simulated solar irradiation. On the basis of the identification of transient species and the competition kinetic model, organic peroxyl radicals were found to play a dominant role in CBZ photodegradation, and the second-order rate constants of the reaction between CBZ and peroxyl radicals were determined to be approximately 107-108 M-1s-1. Furthermore, mutagenic acridine was found to be the major cumulative intermediate with a yield of > 30% in the presence of diketones, which might be an environmental concern. This work indicates that the coexistence of diketones and persistent organic pollutants might lead to some detrimental effects on aquatic environments if the water is exposed to sunlight.
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Affiliation(s)
- Min Xie
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Chengyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Hongcen Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
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17
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Li T, Shang C, Xiang Y, Yin R, Pan Y, Fan M, Yang X. ClO 2 pre-oxidation changes dissolved organic matter at the molecular level and reduces chloro-organic byproducts and toxicity of water treated by the UV/chlorine process. WATER RESEARCH 2022; 216:118341. [PMID: 35367942 DOI: 10.1016/j.watres.2022.118341] [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: 10/18/2021] [Revised: 01/02/2022] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
The formation of undesirable chloro-organic byproducts is of great concern in the UV/chlorine process. In this study, chlorine dioxide (ClO2) pre-oxidation was applied to control the formation of chloro-organic byproducts and the toxicity in UV/chlorine-treated water. The molecular-level changes in dissolved organic matter (DOM) were tracked by using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and ClO2 pre-oxidation was found to preferentially react with DOM moieties with high aromaticity level and with a carbon number of > 18, producing compounds with a higher degree of oxidation and lower aromaticity. The ClO2-treated DOM was found to be less susceptible to attack by radicals and free chlorine in the UV/chlorine process compared to the raw DOM. ClO2 pre-oxidation resulted in a significant decrease in the number of unknown chloro-organic byproducts (i.e., -17%) and the total intensity of organic chlorine detected by FT-ICR-MS (i.e., -31%). The molecular characteristics, such as O/C, aromaticity index, and the average number of chlorine atoms, of these unknown chloro-organic byproducts generated in the scenarios with and without ClO2 pre-oxidation were also different. Additionally, ClO2 pre-oxidation reduced the genotoxicity (SOS/umu test) and cytotoxicity (Hep G2 cytotoxicity assay) of UV/chlorine-treated water by 26% and 20%, respectively. The findings in this study highlight the merits of ClO2 pre-oxidation for controlling chloro-organic byproducts and reducing the toxicity of water treated by the UV/chlorine process in actual practice.
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Affiliation(s)
- Tao Li
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Chii Shang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yingying Xiang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yang Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Mengge Fan
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.
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18
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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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