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Glover CM, Pazoki F, Munoz G, Sauvé S, Liu J. Applying the modified UV-activated TOP assay to complex matrices impacted by aqueous film-forming foams. Sci Total Environ 2024; 924:171292. [PMID: 38432371 DOI: 10.1016/j.scitotenv.2024.171292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/23/2024] [Accepted: 02/24/2024] [Indexed: 03/05/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a large chemical family, and numerous chemical species can co-exist in environmental samples, especially those impacted by aqueous film-forming foams (AFFFs). Given the limited availability of chemical standards, capturing the total amount of PFAS is challenging. Thus, the total oxidizable precursor (TOP) assay has been developed to estimate the total amount of PFAS via the oxidative conversion of precursors into perfluorocarboxylic acids (PFCAs). This study aims to enhance the robustness of the TOP assay by replacing heat activation with UV activation. We evaluated the molar yields of known precursors in water in the presence of varying levels of Suwannee River natural organic matter (SRNOM) and in two soils. The impact of UV activation was also evaluated in two soils spiked with three well-characterized AFFFs, six AFFF-impacted field soils, and nine rinse samples of AFFF-impacted stainless-steel pipe. In the presence of 100 mg/L SNROM, 6:2 fluorotelomer sulfonate (FTS), 8:2 FTS, and N-ethyl perfluorooctane sulfonamidoacetic acid (N-EtFOSAA) in deionized water had good molar recovery as PFCAs (average of 102 ± 9.8 %); at 500 mg/L SNROM, the recovery significantly dropped to an average of 51 ± 19 %. In two soils (with 4 % and 8.8 % organic matter) with individual precursor spikes, the average molar recovery was 101 ± 9.4 %, except N-EtFOSAA, which had a reduced recovery in the soil with 8.8 % organic matter (OM). UV-activated assays outperformed heat-activated ones, especially in AFFF-impacted soils and pipe extract samples, with an average of 1.4-1.5× higher PFCA recovery. In almost all test samples, UV activation resulted in a notable shift towards longer PFCA chain lengths, particularly for samples with high OM content. The study confirmed the advantages of UV activation, including a significantly shortened exposure time (1 h vs. 6 h) and reduced matrix effects from OM due to the dual functions of UV in activating persulfate and photodegrading OM.
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Affiliation(s)
- Caitlin M Glover
- Department of Civil Engineering, McGill University, Montréal, Quebec H3A 0C3, Canada
| | - Faezeh Pazoki
- Department of Civil Engineering, McGill University, Montréal, Quebec H3A 0C3, Canada
| | - Gabriel Munoz
- Département de chimie, Université de Montréal, Montréal, QC H2V 0B3, Canada
| | - Sébastien Sauvé
- Département de chimie, Université de Montréal, Montréal, QC H2V 0B3, Canada
| | - Jinxia Liu
- Department of Civil Engineering, McGill University, Montréal, Quebec H3A 0C3, Canada.
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2
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Asadi Zeidabadi F, Banayan Esfahani E, Moreira R, McBeath ST, Foster J, Mohseni M. Structural dependence of PFAS oxidation in a boron doped diamond-electrochemical system. Environ Res 2024; 246:118103. [PMID: 38181849 DOI: 10.1016/j.envres.2024.118103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/11/2023] [Accepted: 01/02/2024] [Indexed: 01/07/2024]
Abstract
Driven by long-term persistence and adverse health impacts of legacy perfluorooctanoic acid (PFOA), production has shifted towards shorter chain analogs (C4, perfluorobutanoic acid (PFBA)) or fluorinated alternatives such as hexafluoropropylene oxide dimer acid (HFPO-DA, known as GenX) and 6:2 fluorotelomer carboxylic acid (6:2 FTCA). Yet, a thorough understanding of treatment processes for these alternatives is limited. Herein, we conducted a comprehensive study using an electrochemical approach with a boron doped diamond anode in Na2SO4 electrolyte for the remediation of PFOA common alternatives, i.e., PFBA, GenX, and 6:2 FTCA. The degradability, fluorine recovery, transformation pathway, and contributions from electro-synthesized radicals were investigated. The results indicated the significance of chain length and structure, with shorter chains being harder to break down (PFBA (65.6 ± 5.0%) < GenX (84.9 ± 3.3%) < PFOA (97.9 ± 0.1%) < 6:2 FTCA (99.4 ± 0.0%) within 120 min of electrolysis). The same by-products were observed during the oxidation of both low and high concentrations of parent PFAS (2 and 20 mg L-1), indicating that the fundamental mechanism of PFAS degradation remained consistent. Nevertheless, the ratio of these by-products to the parent PFAS concentration varied which primarily arises from the more rapid PFAS decomposition at lower dosages. For all experiments, the main mechanism of PFAS oxidation was initiated by direct electron transfer at the anode surface. Sulfate radical (SO4•-) also contributed to the oxidation of all PFAS, while hydroxyl radical (•OH) only played a role in the decomposition of 6:2 FTCA. Total fluorine recovery of PFBA, GenX, and 6:2 FTCA were 96.5%, 94.0%, and 76.4% within 240 min. The more complex transformation pathway of 6:2 FTCA could explain its lower fluorine recovery. Detailed decomposition pathways for each PFAS were also proposed through identifying the generated intermediates and fluorine recovery. The proposed pathways were also assessed using 19F Nuclear Magnetic Resonance (NMR) spectroscopy.
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Affiliation(s)
- Fatemeh Asadi Zeidabadi
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Ehsan Banayan Esfahani
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Raphaell Moreira
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Sean T McBeath
- Department of Civil and Environmental Engineering, University of Massachusetts Amherst, Amherst, MA, 01002, United States
| | - Johan Foster
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada
| | - Madjid Mohseni
- Department of Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, Canada.
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Li C, Shen C, Gao B, Liang W, Zhu Y, Shi W, Ai S, Xu H, Wu J, Sun Y. Degradation and mechanism of PFOA by peroxymonosulfate activated by nitrogen-doped carbon foam-anchored nZVI in aqueous solutions. Chemosphere 2024; 351:141209. [PMID: 38224751 DOI: 10.1016/j.chemosphere.2024.141209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 12/09/2023] [Accepted: 01/12/2024] [Indexed: 01/17/2024]
Abstract
Perfluorooctanoic acid (PFOA) is an emerging pollutant that is non-biodegradable and presents severe environmental and human health risks. In this study, we present an effective and mild approach for PFOA degradation that involves the use of nitrogen-doped carbon foam anchored with nanoscale zero-valent iron (nZVI@NCF) to activate low concentration peroxymonosulfate (PMS) for the treatment. The nZVI@NCF/PMS system efficiently removed 84.4% of PFOA (2.4 μM). The active sites of nZVI@NCF including Fe0 (110) and graphitic nitrogen played crucial roles in the degradation. Electrochemical analyses and density functional theory calculations revealed that nZVI@NCF acted as an electronic donor, transferring electrons to both PMS and PFOA during the reaction. By further analyzing the electron paramagnetic resonance and byproducts, it was determined that electron transfer and singlet oxygen were responsible for PFOA degradation. Three degradation pathways involving decarboxylation and surface reduction of PFOA in the nZVI@NCF/PMS system were determined. Finding from this study indicate that nZVI@NCF/PMS systems are effective in degrading PFOA and thus present a promising persulfate-advanced oxidation process technology for PFAS treatment.
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Affiliation(s)
- Changyu Li
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China.
| | - Cong Shen
- College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, China
| | - Bin Gao
- Department of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Wenxu Liang
- College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, China
| | - Yifan Zhu
- College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, China
| | - Weijie Shi
- College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, China.
| | - Shiyun Ai
- College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, China
| | - Hongxia Xu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China
| | - Jichun Wu
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China
| | - Yuanyuan Sun
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, China.
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4
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Liu M, Glover CM, Munoz G, Duy SV, Sauvé S, Liu J. Hunting the missing fluorine in aqueous film-forming foams containing per- and polyfluoroalkyl substances. J Hazard Mater 2024; 464:133006. [PMID: 37988941 DOI: 10.1016/j.jhazmat.2023.133006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/16/2023] [Accepted: 11/12/2023] [Indexed: 11/23/2023]
Abstract
Since aqueous film-forming foams (AFFFs) are major sources of per- and polyfluoroalkyl substances (PFAS), understanding the quantity and type of PFAS present in AFFFs is crucial for assessing environmental risk and remediation. We characterized 25 foams from Canada and Europe, including two non-AFFFs and two fluorine-free AFFFs. We used liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) to identify novel PFAS, as well as total oxidizable precursor assays (TOP) and total organofluorine (TOF) measurements for comparison. LC-HRMS showed that the two non-AFFF foams and two PFAS-free AFFFs contained little or no PFAS, confirmed by TOF measurement using combustion ion chromatography (CIC). The PFAS-containing AFFFs, however, spanned a wide concentration range of TOF (2200-45,000 mg F/L) and contained 22 new classes of polyfluoroalkyl substances not previously reported. As a result of identifying new compounds, LC-HRMS was fully able to capture the oxidizable precursors determined by TOP assay in all tested fluorotelomer (FT) AFFFs, while unknown compounds still constituted a significant fraction (19-53 mol%) in most electrochemical fluorination (ECF) AFFFs. A fluorine mass balance was achieved by comparing the amounts of compounds identified by LC-HRMS with those detected by CIC, although LC-HRMS overestimated TOF with a recovery of 127 ± 36%.
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Affiliation(s)
- Min Liu
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Caitlin M Glover
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Gabriel Munoz
- Department of Chemistry, Université de Montréal, Montreal, QC H2V 0B3, Canada
| | - Sung Vo Duy
- Department of Chemistry, Université de Montréal, Montreal, QC H2V 0B3, Canada
| | - Sébastien Sauvé
- Department of Chemistry, Université de Montréal, Montreal, QC H2V 0B3, Canada
| | - Jinxia Liu
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada.
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5
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Bhat AP, Pomerantz WCK, Arnold WA. Fluorinated Pharmaceutical and Pesticide Photolysis: Investigating Reactivity and Identifying Fluorinated Products by Combining Computational Chemistry, 19F NMR, and Mass Spectrometry. Environ Sci Technol 2024. [PMID: 38340057 PMCID: PMC10883306 DOI: 10.1021/acs.est.3c09341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Fluorinated breakdown products from photolysis of pharmaceuticals and pesticides are of environmental concern due to their potential persistence and toxicity. While mass spectrometry workflows have been shown to be useful in identifying products, they fall short for fluorinated products and may miss up to 90% of products. Studies have shown that 19F NMR measurements assist in identifying and quantifying reaction products, but this protocol can be further developed by incorporating computations. Density functional theory was used to compute 19F NMR shifts for parent and product structures in photolysis reactions. Computations predicted NMR spectra of compounds with an R2 of 0.98. Computed shifts for several isolated product structures from LC-HRMS matched the experimental shifts with <0.7 ppm error. Multiple products including products that share the same shift that were not previously reported were identified and quantified using computational shifts, including aliphatic products in the range of -80 to -88 ppm. Thus, photolysis of fluorinated pharmaceuticals and pesticides can result in compounds that are polyfluorinated alkyl substances (PFAS), including aliphatic-CF3 or vinyl-CF2 products derived from heteroaromatic-CF3 groups. C-F bond-breaking enthalpies and electron densities around the fluorine motifs agreed well with the experimentally observed defluorination of CF3 groups. Combining experimental-computational 19F NMR allows quantification of products identified via LC-HRMS without the need for authentic standards. These results have applications for studies of environmental fate and analysis of fluorinated pharmaceuticals and pesticides in development.
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Affiliation(s)
- Akash P Bhat
- Department of Civil, Environmental, and Geo- Engineering University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, Minnesota 55455, United States
| | - William C K Pomerantz
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering University of Minnesota, 500 Pillsbury Dr. SE, Minneapolis, Minnesota 55455, United States
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Chen Z, Chen J, Tan S, Yang Z, Zhang Y. Dechlorination Helps Defluorination: Insights into the Defluorination Mechanism of Florfenicol by S-nZVI and DFT Calculations on the Reaction Pathways. Environ Sci Technol 2024; 58:2542-2553. [PMID: 38262936 DOI: 10.1021/acs.est.3c07435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Defluorination is essential to eliminate the antibiotic resistance and detrimental effects of florfenicol (C12H14Cl2FNO4S, FF), which is achievable by sulfidated nanoscale zerovalent iron (S-nZVI), yet a comprehensive understanding of the mechanism is lacking. Herein, we used experimental data and density functional theory calculations to demonstrate four dechlorination-promoted defluorination pathways of FF, depending on S-nZVI or not. FF was defluorinated in a rapid and then slow but continuous manner, accompanying a consecutive dechlorination to deschloro (dFF) and dideschloro FF (ddFF). Unexpectedly, the predominant defluorination occurs by spontaneous hydrolysis of ddFF to form the hydrolyzed byproduct (HO-ddFF), i.e., independent of S-nZVI, which is initiated by intramolecular attack from carbonyl O to alkyl F and is thus limited for FF and dFF owing to the diminished nucleophilicity by electron-withdrawing Cl. The removal of Cl also makes the reductive defluorination of ddFF by S-nZVI amenable. The other two minor but more rapid defluorination pathways occur in synergy with the dechlorination of FF and dFF, which are mediated by the reactive carbanion intermediates and generate HO-dFF and HO-ddFF, respectively. The reliability of these dechlorination-facilitated defluorination pathways was verified by the consistency of theoretical calculations with experimental data, providing valuable insights into the degradation of fluorinated contaminants.
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Affiliation(s)
- Zhenhuan Chen
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Jingdan Chen
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Shendong Tan
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Zilin Yang
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China
| | - Yanyan Zhang
- Research Center for Industries of the Future, Westlake University, Hangzhou 310030, China
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China
- Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310030, China
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7
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Ding X, Wei C, Wei Y, Liu P, Wang D, Wang Q, Chen X, Song X. Field test of thermally activated persulfate for remediation of PFASs co-contaminated with chlorinated aliphatic hydrocarbons in groundwater. Water Res 2024; 249:120993. [PMID: 38086203 DOI: 10.1016/j.watres.2023.120993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/19/2023] [Accepted: 12/07/2023] [Indexed: 01/03/2024]
Abstract
The co-occurrence of per- and polyfluoroalkyl substances (PFASs) and chlorinated aliphatic hydrocarbons (CAHs) in groundwater has drawn increased attention in recent years. No studies have been conducted concerning the oxidative degradation of PFASs and/or CAHs by in situ thermally activated persulfate (TAP) in groundwater, primarily due to the difficulty in cost-effectively achieving the desired temperature in the field. In this study, the effects and mechanisms of PFASs degradation by in situ TAP at a site with PFASs and CAHs co-contaminants were investigated. The target temperature of 40.0-70.0 °C was achieved in groundwater, and persulfate was effectively distributed in the demonstration area - the combination of which ensured the degradation of PFASs and CAHs co-contaminants by in situ TAP. It was demonstrated that the reductions of perfluoroalkyl carboxylic acids (PFCAs) concentration in all monitoring wells were in the range of 43.7 %-66.0 % by in situ TAP compared to those maximum rebound values in groundwater, whereas no effective perfluoroalkane sulfonic acids (PFSAs) degradation was observed. The conversion of perfluoroalkyl acids (PFAAs) precursors was one of the main factors leading to the increase in PFCAs concentrations in groundwater during in situ TAP. CAHs were effectively degraded in most monitoring wells, and furthermore, no inhibitory effects of CAHs and Cl- on the degradation of PFASs were observed due to the presence of sufficient persulfate. Additionally, there were significant increases in SO42- concentrations and reductions of pH values in groundwater due to in situ TAP, warranting their long-term monitoring in groundwater. The integrated field and laboratory investigations demonstrated that the reductions in PFCAs and CAHs concentrations can be achieved by the oxidative degradation of in situ TAP.
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Affiliation(s)
- Xiaoyan Ding
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Eco-Environmental Research, Guangxi Academy of Sciences, Nanning 530007, China
| | - Changlong Wei
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yunxiao Wei
- BCEG Environmental Remediation Co., Ltd., Beijing 210093, China
| | - Peng Liu
- BCEG Environmental Remediation Co., Ltd., Beijing 210093, China
| | - Dixiang Wang
- BCEG Environmental Remediation Co., Ltd., Beijing 210093, China
| | - Qing Wang
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Chen
- China Construction Eighth Engineering Division Corp., Ltd, Shanghai 200122, China
| | - Xin Song
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Patch D, O'Connor N, Vereecken T, Murphy D, Munoz G, Ross I, Glover C, Scott J, Koch I, Sauvé S, Liu J, Weber K. Advancing PFAS characterization: Enhancing the total oxidizable precursor assay with improved sample processing and UV activation. Sci Total Environ 2024; 909:168145. [PMID: 37952659 DOI: 10.1016/j.scitotenv.2023.168145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 10/22/2023] [Accepted: 10/24/2023] [Indexed: 11/14/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) encompass over 9000 chemicals utilized in various industrial and commercial applications. However, the quantification of PFAS using standard commercial analytical methods is currently limited to <50 selected compounds. To address this issue, the total oxidizable precursor (TOP) assay was developed, allowing for the oxidative conversion of previously undetectable PFAS precursors into measurable PFAS. This study investigated different sample processing methods to address post-oxidation PFAS loss identified in literature. Using PFOS as a probe molecule, up to 50 % loss of PFOS was identified during sample work-up. It was determined that the use of mass-labelled PFOS and methanolic acetic acid to chemically quench the sample post-oxidation improved PFOS recovery and allowed for correction of any remaining PFOS loss. The use of ultraviolet (UV) light was then investigated as an activator in contrast to the standard thermal activation method. A comparative evaluation was conducted to assess the recovery and conversion of perfluorooctanoic acid (PFOA), PFOS, and 6:2 fluorotelomer sulfonate (6:2 FTS) using both the heat-activated and UV-activated TOP assays. Results demonstrated that the UV-activated TOP assay achieved complete (100 %) oxidation of 6:2 FTS within 7.5 min, resulting in a total yield of generated perfluorinated carboxylic acids (PFCAs) at 108 ± 8 %. The study concluded by investigating the UV-activated TOP assay for its application on various aqueous film forming foam (AFFF) formulations and two AFFF samples drained from military aircraft rescue firefighting vehicles (ARFFVs). Analysis of these AFFF samples were supported by high resolution mass spectrometry and an expanded analytical suite, identifying several fluorotelomer precursors. The findings of this study provide compelling evidence that modifications in sample processing, work-up procedures, expansion of initial PFAS calibration standards, and UV-activation methods enhance the TOP assay, positioning it as a more reliable and quantitative analytical tool for PFAS characterization.
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Affiliation(s)
- David Patch
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Natalia O'Connor
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Taylor Vereecken
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Daniel Murphy
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Gabriel Munoz
- Brace Water Center, Department of Civil Engineering, McGill University, Montreal, QB H3A 0G4, Canada
| | - Ian Ross
- CDM Smith, 75 State St #701, Boston, MA 02109, United States of America
| | - Caitlin Glover
- Brace Water Center, Department of Civil Engineering, McGill University, Montreal, QB H3A 0G4, Canada
| | - Jennifer Scott
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Iris Koch
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Sébastien Sauvé
- Département de chimie, Université de Montréal, Montréal, QC H2V 0B3, Canada
| | - Jinxia Liu
- Brace Water Center, Department of Civil Engineering, McGill University, Montreal, QB H3A 0G4, Canada
| | - Kela Weber
- Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada.
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Lorpaiboon W, Ho J. High-Level Quantum Chemical Prediction of C-F Bond Dissociation Energies of Perfluoroalkyl Substances. J Phys Chem A 2023; 127:7943-7953. [PMID: 37722129 DOI: 10.1021/acs.jpca.3c04750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
In this study, 550 C-F bond dissociation energies (BDEs) of a variety of per- and polyfluoroalkyl substances (PFASs) obtained from high-level DLPNO-CCSD(T)/CBS calculations were used to assess the accuracy of contemporary density functional theory (DFT) and semiempirical methods. DLPNO-CCSD(T)/CBS gas phase C-F BDEs fall between 404.9-550.7 kJ mol-1 and M06-2X and ωB97M-V in conjunction with the aug-cc-pVTZ basis set predicted BDEs closest to the benchmark level with a mean absolute deviation (MAD) of 7.3 and 8.3 kJ mol-1, respectively. It was observed that DFT prediction errors increase with the degree of fluorination and system size. As such, previous model chemistry recommendations based on smaller nonfluorinated systems may not be carried over to modeling the energetics of PFASs and related systems.
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Affiliation(s)
- Wanutcha Lorpaiboon
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Junming Ho
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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10
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Zhang C, Xu Y, Liu W, Zhou H, Zhang N, Fang Z, Gao J, Sun X, Feng D, Sun X. New insights into the degradation mechanism and risk assessment of HFPO-DA by advanced oxidation processes based on activated persulfate in aqueous solutions. Ecotoxicol Environ Saf 2023; 263:115298. [PMID: 37499385 DOI: 10.1016/j.ecoenv.2023.115298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 07/09/2023] [Accepted: 07/21/2023] [Indexed: 07/29/2023]
Abstract
Hexafluoropropylene oxide dimer acid (HFPO-DA) is widely used as a substitute for perfluorooctanoic acid (PFOA). HFPO-DA exhibits high water solubility and low adsorption potential, conferring significant fluidity in aquatic environments. Given that the toxicity of HFPO-DA is similar to PFOA, it is necessary to control its content in aquatic environments. Electrochemical and thermally-activated persulfates have been successfully used to degrade HFPO-DA, but UV-activated persulfates cannot degrade the compound. Given that research on degradation mechanisms is still incomplete and lacks kinetic research, the mechanism and kinetic calculations of oxidative degradation were studied in detail using DFT calculations. And the toxicity of HFPO-DA degradation intermediates and products was evaluated to reveal the feasibility of using advanced oxidation process (AOP) technology based on persulfate to degrade HFPO-DA in wastewater. The results showed that the committed step of HFPO-DA degradation was initiated by the electron transfer reaction of SO4•- radicals. This reaction is not spontaneous at room temperature and requires sufficient electrical or thermal energy to be absorbed from the external environment. The perfluoroalcohol produced during this reaction can subsequently undergo four possible reactions: H atom abstraction from alcohol groups by an OH radical; H atom abstraction by SO4•-; direct HF removal; and HF removal with water as the catalyst. The final degradation products of HFPO-DA mainly include CO2, CF3CF2COOH, CF3COOH, FCOOH and HF, which has been identified through previous experimental analysis. Ecotoxicity assessment indicates that degradation does not produce highly toxic intermediates, and that the final products are non-toxic, supporting the feasibility of persulfate-based AOP technologies.
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Affiliation(s)
- Chenxi Zhang
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China; Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Youxin Xu
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China; Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Wenyan Liu
- School of agriculture, Ludong University, Yantai 264025, China
| | - Huaiyu Zhou
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China
| | - Ningning Zhang
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China
| | - Zhihao Fang
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China
| | - Junping Gao
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China
| | - Xiaoan Sun
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China
| | - Di Feng
- Shandong Facility Horticulture Bioengineering Research Center, Weifang University of Science and Technology, Weifang 262700, China.
| | - Xiaomin Sun
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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Xiao HM, Zhao S, Hussain D, Chen JL, Luo D, Wei F, Wang X. Fluoro-cotton assisted non-targeted screening of organic fluorine compounds from rice (Oryza sativa L.) grown in perfluoroalkyl substance polluted soil. Environ Res 2023; 216:114801. [PMID: 36375504 DOI: 10.1016/j.envres.2022.114801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/05/2022] [Accepted: 11/10/2022] [Indexed: 06/16/2023]
Abstract
The toxicity and environmental persistence of perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) are of great concern for food intake in humans. However, PFASs conversion or conjugation to other substances in rice grown on PFASs polluted soil has not been explored clearly. These unknown transformed or conjugated products of PFOA and PFOS could be harmful to human health. The restriction factor in evaluating the possible transformation of PFOA and PFOS is mainly attributed to the lack of an efficient method for screening PFOA and PFOS and their related metabolites. To circumvent this challenge, we established a non-targeted screening method by combining a fluoro-cotton fiber-based solid phase extraction (FC-SPE) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) to monitor the formation of possible organic fluorine compounds from rice (Oryza sativa L.) grown on PFASs. We synthesized fluoro-cotton fibers to serve as the FC-SPE packing material and characterized by field-emission scanning electron-microscope, Fourier transform infrared, and X-ray photoelectron spectroscopy measurements. The optimal extraction conditions for the prepared FC-SPE were investigated. The performance of FC-SPE in LC-MS analysis was validated by linearity, precision, recovery, and matrix effect. Then the FC-SPE combined with LC-HRMS was used to specifically capture organic fluorine compounds from complex matrices via F-F interaction, including rice seedlings grown in PFOA and PFOS polluted soil and soil samples. By the established FC-SPE LC-HRMS method, in total 429 features were found as the possible organic fluorine compounds from rice seedlings grown in PFOA polluted soil among the 1781 features from the rice seedlings. Finally, we employed a13C metabolic tracing analysis of organic fluorine compounds in combination with the FC-SPE LC-HRMS method to further identify the features that detected from rice seedlings grown in PFOA polluted soil. The final result indicated that there were not any new organic fluorine metabolites screened out from rice grown in PFOA or PFOS polluted soil.
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Affiliation(s)
- Hua-Ming Xiao
- Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, 430062, China; Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, College of Chemistry and Materials Science, South-Central Minzu University, Wuhan, 430074, China.
| | - Shuai Zhao
- School of Pharmacy, Changzhou University, Changzhou, 213164, People's Republic of China
| | - Dilshad Hussain
- HEJ Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Pakistan
| | - Jian-Li Chen
- Shimadzu (China) Co., LTD. Wuhan Branch, Wuhan, 430060, China
| | - Dan Luo
- Shimadzu (China) Co., LTD. Wuhan Branch, Wuhan, 430060, China
| | - Fang Wei
- Key Laboratory of Oilseeds Processing of Ministry of Agriculture, Hubei Key Laboratory of Lipid Chemistry and Nutrition, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Xian Wang
- Key Laboratory of Analytical Chemistry of the State Ethnic Affairs Commission, College of Chemistry and Materials Science, South-Central Minzu University, Wuhan, 430074, China
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12
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Wang Q, Ruan Y, Jin L, Lu G, Ma L, Yeung LWY, Wang WX, Lam PKS. Oysters for legacy and emerging per- and polyfluoroalkyl substances (PFASs) monitoring in estuarine and coastal waters: Phase distribution and bioconcentration profile. Sci Total Environ 2022; 846:157453. [PMID: 35863582 DOI: 10.1016/j.scitotenv.2022.157453] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/13/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are a diverse group of widely used anthropogenic chemicals that are environmentally persistent and bioaccumulative, especially in aquatic ecosystem. The heavily industrialized and urbanized Greater Bay Area in China represents a notable contamination source for PFASs, which may potentially influence the health of local oysters as a keystone species in local ecosystems and a popular seafood. In this study, samples of oysters and their surrounding waters were collected from the littoral zones of the Pearl River Estuary (PRE), China during winter 2020, where 44 PFASs, including 19 perfluoroalkyl acids (PFAAs), 8 emerging PFASs, and 17 PFAA precursors (or intermediates), were analyzed. Total PFAS concentrations ranged 13.8-58.8 ng/L in the dissolved phase, 3.60-11.2 ng/g dry weight (dw) in the suspended particulate matter (SPM), and 0.969-1.98 ng/g dw in the oysters. Most short-chain PFASs were present in the dissolved phase (>95%), while long-chain PFASs generally showed higher concentrations in the SPM. Log field-based bioconcentration factors (BCFs) of long-chain PFASs increased linearly (r = 0.95, p < 0.01) with increasing estimated log membrane-water (Dmw) and protein-water (Dpw) distribution coefficients. Perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA) exhibited higher measured BCFs than those estimated by their Dmw and Dpw. Considering the widespread occurrence of their precursors, the contribution of precursor transformation was likely to be a significant source of PFHxA and PFHpA. Oysters from the PRE littoral zones posed low risks to human health associated with PFAS consumption, which might be underestimated due to limited toxicity data available for PFAA precursors and emerging PFASs. This study sheds light on the practicality of applying oysters as biomonitors for timely PFAS monitoring in coastal environments.
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Affiliation(s)
- Qi Wang
- State Key Laboratory of Marine Pollution (SKLMP), Department of Chemistry, City University of Hong Kong, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; Man-Technology-Environment Research Centre (MTM), Örebro University, Örebro, Sweden
| | - Yuefei Ruan
- State Key Laboratory of Marine Pollution (SKLMP), Department of Chemistry, City University of Hong Kong, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
| | - Linjie Jin
- State Key Laboratory of Marine Pollution (SKLMP), Department of Chemistry, City University of Hong Kong, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Guangyuan Lu
- Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Lan Ma
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Leo W Y Yeung
- Man-Technology-Environment Research Centre (MTM), Örebro University, Örebro, Sweden
| | - Wen-Xiong Wang
- Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Paul K S Lam
- State Key Laboratory of Marine Pollution (SKLMP), Department of Chemistry, City University of Hong Kong, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China; Office of the President, Hong Kong Metropolitan University, Hong Kong, China.
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13
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Liu F, Guan X, Xiao F. Photodegradation of per- and polyfluoroalkyl substances in water: A review of fundamentals and applications. J Hazard Mater 2022; 439:129580. [PMID: 35905606 DOI: 10.1016/j.jhazmat.2022.129580] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/05/2022] [Accepted: 07/09/2022] [Indexed: 06/15/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are persistent, mobile, and toxic chemicals that are hazardous to human health and the environment. Several countries, including the United States, plan to set an enforceable maximum contamination level for certain PFAS compounds in drinking water sources. Among the available treatment options, photocatalytic treatment is promising for PFAS degradation and mineralization in the aqueous solution. In this review, recent advances in the abatement of PFAS from water using photo-oxidation and photo-reduction are systematically reviewed. Degradation mechanisms of PFAS by photo-oxidation involving the holes (hvb+) and oxidative radicals and photo-reduction using the electrons (ecb-) and hydrated electrons (eaq-) are integrated. The recent development of innovative heterogeneous photocatalysts and photolysis systems for enhanced degradation of PFAS is highlighted. Photodegradation mechanisms of alternative compounds, such as hexafluoropropylene oxide dimer acid (GenX) and chlorinated polyfluorinated ether sulfonate (F-53B), are also critically evaluated. This paper concludes by identifying major knowledge gaps and some of the challenges that lie ahead in the scalability and adaptability issues of photocatalysis for natural water treatment. Development made in photocatalysts design and system optimization forges a path toward sustainable treatment of PFAS-contaminated water through photodegradation technologies.
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Affiliation(s)
- Fuqiang Liu
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xiaohong Guan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Feng Xiao
- Department of Civil Engineering, University of North Dakota, 243 Centennial Drive Stop 8115, Grand Forks, ND 58202, United States.
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14
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Zhao J, Hu S, Zhu L, Wang W. Formation of chlorinated halobenzoquinones during chlorination of free aromatic amino acids. Sci Total Environ 2022; 825:153904. [PMID: 35189221 DOI: 10.1016/j.scitotenv.2022.153904] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Chlorinated halobenzoquinones (HBQs) widely exist in drinking water as emerging disinfection byproducts (DBPs), which have attracted significant attention due to their wide occurrence and high toxicity. In this study, the formation of chlorinated HBQs from the three free aromatic amino acids, tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe), during chlorination was investigated, the formation pathways of chlorinated HBQs were explained based on the detected intermediates and influence factors. The results revealed that four chlorinated HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,3,5-trichloro-1,4-benzoquinone, 2,3,5,6-tetrachloro-1,4-benzoquinone and 2,6-dichloro-3-methyl-1,4-benzonquinone, were formed in chlorination of the three free aromatic amino acids, and 2,6-DCBQ was the dominant species among the formed chlorinated HBQs. Of the three free aromatic amino acids, Trp and Tyr presented relatively high yields of chlorinated HBQs than Phe. Moreover, ten intermediates were successfully detected (e.g., N,2-dichloroaniline from Trp, 2,4,6-trichlorophenol from Tyr) according to the isotope and fragment information obtained using high resolution mass spectrometry. The formation pathways of chlorinated HBQs from Trp and Tyr were proposed to include electrophilic addition, electrophilic substitution, oxidation, deacidification and dehydration reaction, and further validated using theoretical calculation. The yields of chlorinated HBQs during chlorination of the free aromatic amino acids were significantly affected by free chlorine dosage, pH and temperature.
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Affiliation(s)
- Jiaxing Zhao
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Shaoyang Hu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Lizhong Zhu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Wei Wang
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China.
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