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Ahmadpour E, Debia M. Estimating airborne trichloramine levels in indoor swimming pools using the well-mixed box model. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2024:1-12. [PMID: 38669683 DOI: 10.1080/15459624.2024.2327370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
Exposure to airborne disinfection by-products, especially trichloramine (TCA), could cause various occupational health effects in indoor swimming pools. However, TCA concentration measurements involve specialized analysis conducted in specific laboratories, which can result in significant costs and time constraints. As an alternative, modeling techniques for estimating exposures are promising in addressing these challenges. This study aims to predict airborne TCA concentrations in indoor swimming pools using a mathematical model, the well-mixed box model, found in the IHMOD tool, freely available on the American Industrial Hygiene Association website. The model's predictions are compared with TCA concentrations measured during various bather load scenarios. The research involved conducting 2-hr successive workplace measurements over 16- to 18-hr periods in four indoor swimming pools in Quebec, Canada. TCA concentrations were estimated using the well-mixed box model, assuming a homogeneous mixing of air within the swimming pool environment. A novel approach was developed to estimate the TCA generation rate from swimming pool water, incorporating the number of swimmers in the model. Average measured concentrations of TCA were 0.24, 0.26, 0.14, and 0.34 mg/m3 for swimming pools 1, 2, 3, and 4, respectively. The ratio of these measured average concentrations to their corresponding predicted values ranged from 0.51 to 1.30, 0.67 to 1.04, 0.57 to 1.14, and 0.68 to 1.49 for the respective swimming pools. In a worst-case scenario simulating the swimming pool at full capacity (maximum bathers allowed), TCA concentrations were estimated as 0.23, 0.36, 0.14, and 0.37 mg/m3 for swimming pools 1, 2, 3, and 4. Recalculated concentrations by adjusting the number of swimmers so as not to exceed the recommended occupational limit concentration of 0.35 mg/m3 gives a maximum number of swimmers of 63 and 335 instead of currently 80 and 424 for swimming pools 2 and 4, respectively. Similarly, for swimming pools 1 and 3, the maximum number of swimmers could be 173 and 398 (instead of the current 160 and 225, respectively). These results demonstrated that the model could be used to estimate and anticipate airborne TCA levels in indoor swimming pools across various scenarios.
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Affiliation(s)
- Elham Ahmadpour
- Department of Environmental and Occupational Health, School of Public Health, Le Centre de recherche en santé publique (CreSP), Université de Montréal, Montreal, Canada
| | - Maximilien Debia
- Department of Environmental and Occupational Health, School of Public Health, Le Centre de recherche en santé publique (CreSP), Université de Montréal, Montreal, Canada
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Chuang YH, Chen TY, Chou CS, Chu LK, Hou CY, Szczuka A. Critical Role of Trichloramine Interaction with Dichloramine for N-Nitrosamine Formation during Breakpoint Chlorination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15232-15242. [PMID: 37603422 DOI: 10.1021/acs.est.3c03326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Breakpoint chlorination is prevalent in drinking water and potable reuse water treatment. Breakpoint chlorination enhances the formation of N-nitrosamines through reactions that form nitrosating agents. The most recent study suggests that nitroxyl (HNO) can react with free chlorine (HOCl) to form the nitrosyl chloride (ClNO) nitrosating agent but has not experimentally verified its importance in breakpoint chlorination. This study first assessed the formation of N-nitrosamines from model N-chloro-alkylamine precursors when they were added to a mixture of HOCl and HNO-derived nitrosating agents generated by chlorinating hydroxyurea. Results demonstrated negligible N-nitrosamine formation. Instead, we observed that the interaction of NCl3 with NHCl2 (total Cl2/total N molar ratio = 2.4-3:1) produced an intermediate capable of nitrosating N-chloro-alkylamines to N-nitrosamines at yields 8-fold higher to those observed in NHCl2 treatment alone, within a very short timescale (<3 min). We examined the stoichiometry of the reaction of NCl3 with NHCl2 using a UV-spectrum-based approach. Nitrosyl chloride was proposed as the key intermediate, likely formed alongside the reformation of NHCl2. Further isotopic experiments, byproduct measurements, and kinetic modeling supported the hypotheses. Modeling indicated that the reaction of NCl3 with NHCl2 explained ∼75% of NDMA formation during breakpoint chlorination. Because NCl3 is mainly derived from the reaction of HOCl with NHCl2, controlling NHCl2 (e.g., with additional treatment) is critical for minimizing nitrosamine formation in waters where breakpoint chlorination occurs.
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Affiliation(s)
- Yi-Hsueh Chuang
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Ting-Yuan Chen
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Chia-Shun Chou
- Institute of Environmental Engineering, National Yang Ming Chiao Tung University, 1001, University Rd., Hsinchu City 30010, Taiwan
| | - Li-Kang Chu
- Department of Chemistry, National Tsing Hua University, 101, Sec 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Chun-Yao Hou
- Department of Chemistry, National Tsing Hua University, 101, Sec 2, Kuang-Fu Rd., Hsinchu 300044, Taiwan
| | - Aleksandra Szczuka
- Department of Civil and Environmental Engineering, University of Michigan, 1351 Beal Ave. Ann Arbor, Michigan 48109, United States
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Ahmadpour E, Delpla I, Debia M, Simard S, Proulx F, Sérodes JB, Valois I, Tardif R, Haddad S, Rodriguez M. Full-scale multisampling and empirical modeling of DBPs in water and air of indoor pools. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:1128. [PMID: 37650940 DOI: 10.1007/s10661-023-11619-6] [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: 09/21/2022] [Accepted: 07/19/2023] [Indexed: 09/01/2023]
Abstract
Disinfection by-products (DBPs) are formed in the water in swimming pools due to reactions between disinfectants (chlorine, bromine, ozone) and the organic matter introduced by bathers and supply water. High concentrations of DBPs are also reported in the air of indoor swimming pools. Based on a robust multisampling program, the levels and variations of DBPs in the air (trichloramine [TCAM] and trihalomethanes [THMs]) and water (THM) were assessed, as well as their precursors (total organic carbon, water temperature, pH, free, and total chlorine) and proxies (CO2 and relative humidity) in four indoor chlorinated swimming pools. High-frequency sampling was conducted during one high-attendance day for each pool. This study focused on parameters that are easy to measure in order to develop models for predicting levels of THMs and TCAM in the air. The results showed that the number of bathers had an important impact on the levels of THMs and TCAM, with a two-to-three-fold increase in air chloroform (up to 110 μg/m3) and a two-to-four-fold increase in TCAM (up to 0.52 mg/m3) shortly after pools opened. The results of this study for the first time showed that CO2 and relative humidity can serve as proxies for monitoring variations in airborne THMs and TCAM. Our results highlight the good predictive capacity of the developed models and their potential for use in day-to-day monitoring. This could help optimize and control DBPs formation in the air of indoor swimming pools and reduce contaminant exposure for both pool employees and users.
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Affiliation(s)
- Elham Ahmadpour
- Department of Occupational & Environmental Health, School of Public Health, Universite de Montreal, 2900, Boulevard Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Ianis Delpla
- Ecole superieure d'amenagement du territoire et de developpement regional (ESAD), Université Laval, Pavillon F-A. Savard, 2325, rue des Bibliothèques, local 1612, Quebec, QC, G1V 0A6, Canada.
| | - Maximilien Debia
- Department of Occupational & Environmental Health, School of Public Health, Universite de Montreal, 2900, Boulevard Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Sabrina Simard
- Ecole superieure d'amenagement du territoire et de developpement regional (ESAD), Université Laval, Pavillon F-A. Savard, 2325, rue des Bibliothèques, local 1612, Quebec, QC, G1V 0A6, Canada
| | - François Proulx
- Ecole superieure d'amenagement du territoire et de developpement regional (ESAD), Université Laval, Pavillon F-A. Savard, 2325, rue des Bibliothèques, local 1612, Quebec, QC, G1V 0A6, Canada
| | - Jean-Baptiste Sérodes
- Ecole superieure d'amenagement du territoire et de developpement regional (ESAD), Université Laval, Pavillon F-A. Savard, 2325, rue des Bibliothèques, local 1612, Quebec, QC, G1V 0A6, Canada
| | - Isabelle Valois
- Department of Occupational & Environmental Health, School of Public Health, Universite de Montreal, 2900, Boulevard Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Robert Tardif
- Department of Occupational & Environmental Health, School of Public Health, Universite de Montreal, 2900, Boulevard Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Sami Haddad
- Department of Occupational & Environmental Health, School of Public Health, Universite de Montreal, 2900, Boulevard Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Manuel Rodriguez
- Ecole superieure d'amenagement du territoire et de developpement regional (ESAD), Université Laval, Pavillon F-A. Savard, 2325, rue des Bibliothèques, local 1612, Quebec, QC, G1V 0A6, Canada
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Shan P, Lin J, Zhai Y, Dong S, How ZT, Qin R. Transformation and toxicity studies of UV filter diethylamino hydroxybenzoyl hexyl benzoate in the swimming pools. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163498. [PMID: 37068670 DOI: 10.1016/j.scitotenv.2023.163498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 06/01/2023]
Abstract
Diethylamino hydroxybenzoyl hexyl benzoate (DHHB), an ultraviolet (UV) filter, can be found in sunscreens and other personal care products and thus can be introduced into swimming pools through the swimmers. In outdoor pools, DHHB will inevitably interact with free chlorine and sunlight. Therefore, the mechanism of solar‑chlorine chemical transformation of DHHB, as well as the environmental risk, were investigated in this work. In chlorinated with solar (Cl + solar) process, free chlorine was the dominant contributor to 85% of the DHHB degradation, while hydroxyl radicals and reactive chlorine species contributed only 15% because of low free radical generation and fast DHHB and free chlorine reaction rates. Scavenging matrices, such as Cl-, NH4+, and dissolved organic matter (DOM), inhibited the degradation of DHHB in the Cl + solar process, while Br-, HCO3-, NO3-, and urea promoted DHHB degradation. DHHB degradation was inhibited in tap water swimming pool samples, while it was enhanced in seawater pool samples by the Cl + solar process. Seven transformation by-products (TBPs) including mono-, dichlorinated, dealkylate, and monochloro-hydroxylated TBPs were identified. Three degradation pathways, chlorine substitution, chlorine and hydroxyl substitution, and dealkylation were proposed for DHHB transformation in the Cl + solar process. Both Quantitative structure-activity relationship and Aliivibrio fischeri toxicity tests demonstrated increased toxicity for the chlorinated TBPs. A risk assessment of the DHHB and its TBPs suggested that both DHHB and its chlorinated TBPs pose a significant health risk.
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Affiliation(s)
- Panduo Shan
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Jiayi Lin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Yanbo Zhai
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Shuai Dong
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan 570228, PR China
| | - Zuo Tong How
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Rui Qin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China.
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5
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Huang H, Zheng H, Jiao J, Lei Y, Zhou Y, Qiu J, Yang X. Trichloramine and Hydroxyl Radical Contributions to Dichloroacetonitrile Formation Following Breakpoint Chlorination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12592-12601. [PMID: 35976682 DOI: 10.1021/acs.est.2c03701] [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] [Indexed: 06/15/2023]
Abstract
Breakpoint chlorination is applied to remove ammonia in water treatment. Trichloramine (NCl3) and transient reactive species can be present, but how they affect the formation of nitrogenous disinfection byproducts is unknown. In this study, the dichloroacetonitrile (DCAN) formation mechanisms and pathways involved during breakpoint chlorination (i.e., free chlorine to ammonia molar ratio ≥2.0) were investigated. DCAN formation during breakpoint chlorination of natural organic matter (NOM) isolates was 14.3-20.3 μg/L, which was 2-10 times that in chlorination without ammonia at similar free chlorine residual conditions (2.1-2.9 mg/L as Cl2). The probe tests and electron paramagnetic resonance spectra supported the presence of •OH, •NO, and NCl3 besides free chlorine in breakpoint chlorination. 15N-labeled ammonium-N tests indicated the incorporation of ammonium-N in DCAN formation though ammonia was eliminated during breakpoint chlorination. Aromatic non-nitrogenous moieties, such as phenols (i.e., none DCAN precursors in the free-chlorine-only system), became DCAN precursors during breakpoint chlorination. The reactions involved in reactive nitrogen species, such as •NO/•NO2 and NCl3, led to additional nitrogen sources in DCAN formation, accounting for 36-84% of total nitrogen sources in DCAN formation from NOM isolates and real water samples. Scavenging •OH by tert-butanol reduced DCAN formation by 40-56%, indicating an important role of •OH in transforming DCAN precursors. This study improves the understanding of breakpoint chlorination chemistry.
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Affiliation(s)
- Huang Huang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Hangcong 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
| | - Jiajia Jiao
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu Lei
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Yangjian Zhou
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Junlang Qiu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- 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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6
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Sun Q, Wu S, Yin R, Bai X, Bhunia AK, Liu C, Zheng Y, Wang F, Blatchley ER. Effects of fulvic acid size on microcystin-LR photodegradation and detoxification in the chlorine/UV process. WATER RESEARCH 2021; 193:116893. [PMID: 33582494 DOI: 10.1016/j.watres.2021.116893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 06/12/2023]
Abstract
Microcystin-LR (MC-LR), a polypeptide toxin generated by cyanobacteria, threatens the safety of drinking water supplies. In this study, fulvic acid (FA) was separated into two molecular weight (MW) ranges to evaluate the effects of FA size on MC-LR degradation in the chlorine/UV process. The rates of MC-LR degradation were significantly reduced in FA-containing water (3.7 × 10-3 s-1 for small MW FA; 4.3 × 10-3 s-1 for large MW FA) as compared with FA free water (4.9 × 10-3 s-1). The contributions of ClO• to MC-LR degradation were dramatically lower in small MW FA water (0.4%) than large MW FA (13.9%) and FA free water (17.4%), suggesting inhibition by lignin-like substances in FA in the transformation of Cl• to ClO• and scavenging ClO•. Monochlorination and hydroxylation occurred in the first step of the MC-LR degradation process. The accumulation of intermediate products in the chlorine/UV process indicated that small MW FA inhibited further degradation of MC-LR. Small MW FA, rather than MC-LR degradation, was the dominant factor in minimizing MC-LR cytotoxicity toward a human intestinal epithelial cell line.
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Affiliation(s)
- Qiyuan Sun
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China; Lyles School of Civil Engineering, Purdue University, West Lafayette, IN, 47907, United States; Fujian Key Laboratory of Pollution Control & Resource Reuse, Fuzhou, Fujian, 350007, China
| | - Shanbin Wu
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, 47907, United States
| | - Arun K Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, 47907, United States
| | - Changqing Liu
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China; Fujian Key Laboratory of Pollution Control & Resource Reuse, Fuzhou, Fujian, 350007, China
| | - Yuyi Zheng
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China; Fujian Key Laboratory of Pollution Control & Resource Reuse, Fuzhou, Fujian, 350007, China
| | - Feifeng Wang
- College of Environmental Science and Engineering, Fujian Normal University, Fuzhou, Fujian, 350007, China; Fujian Key Laboratory of Pollution Control & Resource Reuse, Fuzhou, Fujian, 350007, China.
| | - Ernest R Blatchley
- Lyles School of Civil Engineering, Purdue University, West Lafayette, IN, 47907, United States; Division of Environmental & Ecological Engineering, Purdue University, West Lafayette, IN, 47907, United States.
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7
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Wang S, Zhu G, Yu Z, Li C, Wang D, Cao X. Mineralization of petrochemical wastewater after biological treatment by ozonation catalyzed with divalent iron tartaric acid chelate. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 81:2211-2220. [PMID: 32701498 DOI: 10.2166/wst.2020.287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The petrochemical wastewater includes many toxic organic compounds, which are refractory substances. It is difficult for the wastewater to meet discharge standards after biological treatment, therefore, the further effective treatment of post-biochemical petrochemical wastewater has become an urgent problem to be solved. This study used iron tartaric acid chelate (ITC) catalytic ozonation to treat the petrochemical wastewater. Various key factors were investigated, such as hydraulic retention time (HRT), catalyst dosage, ozone concentration, initial pH values and oxidation efficiency. The kinetics of catalytic ozonation were established. The results indicate that the chemical oxygen demand (COD) removal rate reached a maximum of 58.5%, when the Fe2+ dosage is 0.25 mmol L-1, the initial pH value is neutral, the liquid phase ozone concentration is about 1.95 mg L-1, and HRT is equal to 180 min. In addition, when HRT is equal to 90 min, the B/C ratio of wastewater increases to 0.31, the catalytic ozone reaches maximum oxidation efficiency, and the most economical HRT was 90 min. Finally, the kinetics of ITC catalytic ozonation catalyzed with ITC is consistent with the pseudo-first-order kinetic reaction, and its rate constant is 0.00484 min-1.
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Affiliation(s)
- Song Wang
- School of Earth Science, Northeast Petroleum University, Daqing, China
| | - Genwang Zhu
- School of Earth Science, Northeast Petroleum University, Daqing, China
| | - Zhongchen Yu
- School of Civil Architecture Engineering, Northeast Petroleum University, Daqing, China E-mail:
| | - Chenxi Li
- School of Engineering, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Dan Wang
- School of Earth Science, Northeast Petroleum University, Daqing, China
| | - Xiaoling Cao
- School of Civil Architecture Engineering, Northeast Petroleum University, Daqing, China E-mail:
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8
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Sharma VK, Feng M. Water depollution using metal-organic frameworks-catalyzed advanced oxidation processes: A review. JOURNAL OF HAZARDOUS MATERIALS 2019; 372:3-16. [PMID: 28993029 DOI: 10.1016/j.jhazmat.2017.09.043] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/22/2017] [Accepted: 09/25/2017] [Indexed: 05/29/2023]
Abstract
This paper presents a review on the environmental applications of metal-organic frameworks (MOFs), which are inorganic-organic hybrid highly porous crystalline materials, prepared from metal ion/clusters and multidentate organic ligands. The emphases are made on the enhancement of the performance of advanced oxidation processes (AOPs) (photocatalysis, Fenton reaction methods, and sulfate radical (SO4-)-mediated oxidations) using MOFs materials. MOFs act as adsorption and light absorbers, leading to superior performance of photocatalytic processes. More recent examples of photocatalytic degradation of dyes are presented. Additionally, it is commonly shown that Fe-based MOFs exhibited excellent catalytic performance on the Fenton-based and SO4•--mediated oxidations of organic pollutants (e.g., dyes, phenol and pharmaceuticals). The significantly enhanced generation of reactive species such as OH and/or SO4- by both homogeneous and heterogeneous catalysis was proposed as the possible mechanism for water depollution. Based on the existing literature, the challenge and future perspectives in MOF-based AOPs are addressed.
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Affiliation(s)
- Virender K Sharma
- Program for the Environment and Sustainability, Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, 212 Adriance Lab Road, 1266 TAMU College Station, TX 77843, USA.
| | - Mingbao Feng
- Program for the Environment and Sustainability, Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, 212 Adriance Lab Road, 1266 TAMU College Station, TX 77843, USA
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9
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Li M, Hao M, Yang L, Yao H, Bolton JR, Blatchley ER, Qiang Z. Trace Organic Pollutant Removal by VUV/UV/chlorine Process: Feasibility Investigation for Drinking Water Treatment on a Mini-Fluidic VUV/UV Photoreaction System and a Pilot Photoreactor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7426-7433. [PMID: 29792423 DOI: 10.1021/acs.est.8b00611] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The vacuum-ultraviolet/ultraviolet/chlorine (VUV/UV/chlorine) process, with a VUV/UV mercury lamp used as the light source, was found to be a highly efficient advanced oxidation process (AOP) in a previous study. Hence, its application feasibility for trace organic pollutant removal from drinking water becomes attractive. In this work, a bench-scale mini-fluidic VUV/UV photoreaction system was used to determine the degradation kinetics of sulfamethazine (SMN), a model sulfonamide antibiotic frequently detected with trace levels in aquatic environments. Results indicated that SMN (0.1 mg L-1) could be degraded rapidly by VUV/UV/chlorine, and a synergism was observed between the VUV/UV and UV/chlorine processes. Photon-fluence based rate constants of SMN degradation were determined to be 6.76 × 103 and 8.51 × 103 m2 einstein-1 at chlorine doses of 0.05 and 0.5 mg L-1, respectively. The presence of natural organic matter in real waters significantly inhibited SMN degradation. In addition, pilot tests were conducted to explore the practical performance of the VUV/UV/chlorine process, thereby allowing electrical energy per order to be calculated for cost evaluation. The effect of flow pattern on photoreactor efficiency was also analyzed by computational fluid dynamics simulations. Both bench- and pilot-scale tests have demonstrated that the VUV/UV/chlorine process, as a new AOP, has potential applications to trace organic pollutant removal in small-scale water treatment.
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Affiliation(s)
- Mengkai Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , University of Chinese Academy of Sciences, Chinese Academy of Sciences , 18 Shuang-qing Road , Beijing 100085 , China
- Lyles School of Civil Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Mengyu Hao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , University of Chinese Academy of Sciences, Chinese Academy of Sciences , 18 Shuang-qing Road , Beijing 100085 , China
- Department of Municipal and Environmental Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - Laxiang Yang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , University of Chinese Academy of Sciences, Chinese Academy of Sciences , 18 Shuang-qing Road , Beijing 100085 , China
| | - Hong Yao
- Department of Municipal and Environmental Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - James R Bolton
- Department of Civil and Environmental Engineering , University of Alberta , Edmonton , AB T6G 1H9 , Canada
| | - Ernest R Blatchley
- Lyles School of Civil Engineering , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Zhimin Qiang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , University of Chinese Academy of Sciences, Chinese Academy of Sciences , 18 Shuang-qing Road , Beijing 100085 , China
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10
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Zhang T, Xu B, Wang A, Cui C. Degradation kinetics of organic chloramines and formation of disinfection by-products during chlorination of creatinine. CHEMOSPHERE 2018; 195:673-682. [PMID: 29289012 DOI: 10.1016/j.chemosphere.2017.12.113] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/16/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
Organic chloramines can interfere with the measurement of effective combined chlorine in chlorinated water and are potential intermediate products of highly toxic disinfection by-products (DBPs). In order to know more about the degradation and transformation of organic chloramines, a typical organic chloramine precursor creatinine was selected for investigation and a corresponding individual organic chloramine chlorocreatinine was prepared in this study. The preparation condition of chlorocreatinine by chlorination was established as chlorine/creatinine = 1 M/M, reaction time = 2 h and pH = 7.0. Then the degradation kinetics of chlorocreatinine during further chlorination was studied, and a second-order rate constant of 1.16 (±0.14) M-1 s-1 was obtained at pH 7.0. Solution pH significantly influenced the degradation rate, and the elementary rate constants of chlorocreatinine with HOCl+H+, HOCl, OCl- and chlorocreatinine- with OCl- were calculated as 2.43 (±1.55) × 104 M-2 s-1, 1.05 (±0.09) M-1 s-1, 2.86 (±0.30) M-1 s-1 and 3.09 (±0.24) M-1 s-1, respectively. Besides, it was found that chlorocreatinine could be further converted into several C-DBPs (chloroform and trichloroacetone) and N-DBPs (dichloroacetonitrile (DCAN) and trichloronitromethane (TCNM)) during chlorination. The total yield of DBPs increased obviously with increasing pH, especially for TCNM. In addition, the presence of humic acid in creatinine solution could increase the formation of DCAN obviously during chlorination. Based on the UPLC-Q-TOF-MS analysis, the conversion pathways of chlorocreatinine were proposed. Several kinds of intermediate products were also identified as organic chloramines and some of them could even exist stably during the further chlorination.
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Affiliation(s)
- Tianyang Zhang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China; State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Bin Xu
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
| | - Anqi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Changzheng Cui
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
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Matsushita T, Matsui Y, Ikekame S, Sakuma M, Shirasaki N. Trichloramine Removal with Activated Carbon Is Governed by Two Reductive Reactions: A Theoretical Approach with Diffusion-Reaction Models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4541-4548. [PMID: 28355057 DOI: 10.1021/acs.est.6b05461] [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
Mechanisms underlying trichloramine removal with activated carbon treatment were proven by batch experiments and theoretical analysis with diffusion-reaction models. The observed values of trichloramine and free chlorine were explained only by the model in which (1) both trichloramine and free chlorine were involved as reactants, (2) the removals of reactants were affected both by the intraparticle diffusion and by the reaction with activated carbon, and (3) trichloramine decomposition was governed by two distinct reductive reactions. One reductive reaction was expressed as a first-order reaction: the reductive reaction of trichloramine with the basal plane of PAC, which consists of graphene sheets. The other reaction was expressed as a second-order reaction: the reductive reaction of trichloramine with active functional groups located on the edge of the basal plane. Free chlorine competitively reacted with both the basal plane and the active functional groups. The fact that the model prediction succeeded even in experiments with different activated carbon doses, with different initial trichloramine concentrations, and with different sizes of activated carbon particles clearly proved that the mechanisms described in the model were reasonable for explaining trichloramine removal with activated carbon treatment.
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Affiliation(s)
- Taku Matsushita
- Graduate School of Engineering, Hokkaido University , N13W8, Sapporo 060-8628, Japan
| | - Yoshihiko Matsui
- Graduate School of Engineering, Hokkaido University , N13W8, Sapporo 060-8628, Japan
| | - Shohei Ikekame
- Graduate School of Engineering, Hokkaido University , N13W8, Sapporo 060-8628, Japan
| | - Miki Sakuma
- National Institute of Technology, Kisarazu College , 2-11-1 Kiyomidai Higashi, Kisarazu 292-0041, Japan
| | - Nobutaka Shirasaki
- Graduate School of Engineering, Hokkaido University , N13W8, Sapporo 060-8628, Japan
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12
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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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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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Letourneau DR, Gill CG, Krogh ET. Photosensitized degradation kinetics of trace halogenated contaminants in natural waters using membrane introduction mass spectrometry as an in situ reaction monitor. Photochem Photobiol Sci 2015; 14:2108-18. [DOI: 10.1039/c5pp00286a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
On-line membrane introduction mass spectrometry used to directly measure the photosensitized reductive dehalogenation kinetics of trace aqueous halocarbons in the presence of naturally occurring dissolved organic matter.
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Affiliation(s)
- Dane R. Letourneau
- Applied Environmental Research Laboratories
- Department of Chemistry
- Nanaimo
- Canada
- University of Victoria
| | - Chris G. Gill
- Applied Environmental Research Laboratories
- Department of Chemistry
- Nanaimo
- Canada
- University of Victoria
| | - Erik T. Krogh
- Applied Environmental Research Laboratories
- Department of Chemistry
- Nanaimo
- Canada
- University of Victoria
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