1
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Zhou D, Liu H, Huang Y, Li Y, Wang N, Wang J. Overlooked role of CO 3· - reactivity with different dissociation forms of organic micropollutants in degradation kinetics modeling: A case study of fluoxetine degradation in a UV/peroxymonosulfate system. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135538. [PMID: 39173383 DOI: 10.1016/j.jhazmat.2024.135538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/27/2024] [Accepted: 08/14/2024] [Indexed: 08/24/2024]
Abstract
Selective oxidizing agent carbonate radical (CO3•-) is an important secondary radical in radical-based advanced oxidation technology for wastewater treatment. However, the role of CO3•- in removing ionizable organic micropollutants (OMs) under environmentally relevant conditions remains unclear. Herein we investigated CO3•- effect on degradation kinetics of fluoxetine in UV/peroxymonosulfate (PMS) system based on a built radical model considering CO3•- reactivity differences with its different dissociation forms. Results revealed that the model, which incorporated CO3•- selective reactivity (with determined second-order rate constants, ksrc,CO3·-, of 7.33 ×106 and 2.56 ×108 M-1s-1 for cationic and neutral fluoxetine, respectively) provided significantly more accurate predictions of fluoxetine degradation rates (k). A good linear correlation was observed between ksrc,CO3·- from experiments and literatures for 24 ionizable OMs and their molecular orbital energy gaps and oxidation potentials, suggesting the possible electron transfer reaction mechanism. Cl- slightly reduced the degradation rates of fluoxetine owing to rapid transformation of Cl• with HCO3- into CO3•-, which partially compensated for the quenching effects of Cl- on HO• and SO4•-. Dissolved organic matter significantly quenched reactive radicals. The constructed kinetic model successfully predicted fluoxetine degradation rates in real waters, with CO3•- being the dominant contributor (∼90 %) to this degradation process.
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Affiliation(s)
- Die Zhou
- School of Resources and Environment, Linyi University, Linyi, Shandong 276000, China; Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Huaying Liu
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Yixi Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Yingjie Li
- School of Resources and Environment, Linyi University, Linyi, Shandong 276000, China; Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
| | - Nian Wang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Jin Wang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
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2
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Yan Y, Meng Y, Miu K, Wenk J, Anastasio C, Spinney R, Tang CJ, Xiao R. Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8966-8975. [PMID: 38722667 DOI: 10.1021/acs.est.4c00246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The absolute radical quantum yield (Φ ) is a critical parameter to evaluate the efficiency of radical-based processes in engineered water treatment. However, measuring Φ is fraught with challenges, as current quantification methods lack selectivity, specificity, and anti-interference capabilities, resulting in significant error propagation. Herein, we report a direct and reliable time-resolved technique to determine Φ at pH 7.0 for commonly used radical precursors in advanced oxidation processes. For H2O2 and peroxydisulfate (PDS), the values of Φ •OH and Φ SO 4 • - at 266 nm were measured to be 1.10 ± 0.01 and 1.46 ± 0.05, respectively. For peroxymonosulfate (PMS), we developed a new approach to determine Φ • OH PMS with terephthalic acid as a trap-and-trigger probe in the nonsteady state system. For the first time, the Φ • OH PMS value was measured to be 0.56 by the direct method, which is stoichiometrically equal to Φ SO 4 • - PMS (0.57 ± 0.02). Additionally, radical formation mechanisms were elucidated by density functional theory (DFT) calculations. The theoretical results showed that the highest occupied molecular orbitals of the radical precursors are O-O antibonding orbitals, facilitating the destabilization of the peroxy bond for radical formation. Electronic structures of these precursors were compared, aiming to rationalize the tendency of the Φ values we observed. Overall, this time-resolved technique with specific probes can be used as a reliable tool to determine Φ , serving as a scientific basis for the accurate performance evaluation of diverse radical-based treatment processes.
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Affiliation(s)
- Yiqi Yan
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Yunxiang Meng
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Kanying Miu
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Jannis Wenk
- Department of Chemical Engineering, Water Innovation & Research Centre (WIRC@Bath), University of Bath, Bath BA2 7AY, U.K
| | - Cort Anastasio
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
| | - Richard Spinney
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chong-Jian Tang
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
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3
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Kang L, Jiang Y, Tian Y, Zou J, Feng L, Liu Y, Han Q, Zhang L. Unveiling the enhancement mechanisms of algogenic extracellular organic matters on chlortetracycline photodegradation: Constitutive relationships of compound components and reactive oxygen species generation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167015. [PMID: 37734609 DOI: 10.1016/j.scitotenv.2023.167015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/08/2023] [Accepted: 09/10/2023] [Indexed: 09/23/2023]
Abstract
Algogenic extracellular organic matters (EOMs) have been found to play a crucial role in the photodegradation of antibiotics. However, the specific molecular structure compositions of EOMs have not been fully characterized, and the intrinsic association between the structure and the production of ROS remains unclear. In this study, EOMs from Chlorella Vulgaris were characterized using FT-ICR-MS. Based on the FT-ICR-MS results, nine representative model compounds (MCs, i.e., benzene, naphthalene, anthracene, phenanthrene, glucose, l-glutamic, triglyceride, tannic and lignin) were applied to investigate the physicochemical properties of EOMs and the ROS changes induced by the photoreaction of chlortetracycline (CTC). With the help of quenching assays, nine MCs were classified into prone-ROS and non-prone-ROS fractions. Prone-ROS compounds generate O2- upon electron transfer to 3O2, which then produces ·OH after disproportionation to generate hydrogen peroxide. The formation of 1O2 is attributed to energy transfer from prone-ROS to 3O2. Density functional theory revealed that prone-ROS exhibited higher reactivity compared to non-prone-ROS, this finding is as well supported by the result of steady-state photolysis measurement. Our study gives a new insight into photochemical fate of CTC in aquatic environments, providing theoretical basis for assessing antibiotics' ecological risk accurately.
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Affiliation(s)
- Longfei Kang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China.
| | - Yixin Jiang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Yajun Tian
- College of Environment, Zhejiang University of Technology, Chaowang Road 18, Hangzhou 310014, China
| | - Jinru Zou
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Qi Han
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, 35 Qinghua East Road, Haidian District, Beijing 100083, China.
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4
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Tao J, Shen T, Kang L, Zhang L, Liu Y, Tian Y, Feng L. Unveil the mechanism of photosensitized fluoroquinolones enhancing chlortetracycline photodegradation under simulated sunlight: Batch experiments and DFT calculation. ENVIRONMENTAL RESEARCH 2023; 237:116961. [PMID: 37619632 DOI: 10.1016/j.envres.2023.116961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 08/26/2023]
Abstract
Fluoroquinolones (FQs), as the most commonly used antibiotics, are ubiquitous in the aquatic environment. The FQs' self-sensitization process could generate reactive oxygen species (ROS), which could react with other coexisting organic pollutants, impacting their transformation behaviors. However, the FQs' influences and mechanisms on the photochemical transformation of coexisting antibiotics are not yet revealed. In this study, we found ofloxacin (OFL) and norfloxacin (NOR), the two common FQs, can obviously accelerate chlortetracycline (CTC) photodegradation. In the presence of OFL and NOR (i.e., 10 μM), CTC photodegradation rate constants increased by 181.1% and 82.9%, respectively. With the help of electron paramagnetic resonance (EPR) and quenching experiments, this enhancement was attributed to aromatic ketone structure in FQs, which absorbed photons to generate ROS (i.e., 3OFL*, 3NOR*,1O2, and •OH). Notably, 3OFL* or 3NOR* was dominantly contributed to the enhanced CTC photodegradation, with the contribution ratios of 79.9% and 77.3% in CTC indirect photodegradation, respectively. Compared to CTC direct photodegradation, some new photodegradation products were detected in FQs solution, suggesting that 3OFL* or 3NOR* may oxide CTC through electron transfer. Moreover, the higher triple-excited state energy of OFL and NOR over DFT calculation implied that energy transfer from 3OFL* or 3NOR* to CTC was also theoretically feasible. Therefore, the presence of FQs could significantly accelerate the photodegradation of coexisting antibiotics mainly via electron or energy transfer of 3FQs*. The present study provided a new insight for accurately evaluating environmental behaviors and risks when multiple antibiotics coexist.
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Affiliation(s)
- Jiaqi Tao
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Tianyi Shen
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Longfei Kang
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Liqiu Zhang
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yongze Liu
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yajun Tian
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China.
| | - Li Feng
- College of Environment Science and Technology, Beijing Forestry University, Beijing, 100083, China.
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5
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Kong S, Liu X, Jiang H, Hong W, Zhang J, Song W, Yan S. Photobleaching-induced changes in the optical and photochemical properties of algal organic matter. WATER RESEARCH 2023; 243:120395. [PMID: 37549448 DOI: 10.1016/j.watres.2023.120395] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/09/2023]
Abstract
Algal organic matter (AOM), a significant source of endogenous dissolved organic matter (DOM) is released in high concentrations during cyanobacterial blooms, along with cyanotoxins. Subsequent photobleaching of AOM is an important phenomenon to investigate. In this study, intracellular organic matter (IOM) and extracellular organic matter (EOM) were extracted from cultured cyanobacteria taken from Taihu Lake in China. The formation of photochemically produced reactive intermediates in different stages of IOM and EOM photobleaching was compared to Suwannee River DOM (SRDOM, reference standard DOM). Results revealed notable differences influenced by the pigment component among IOM, EOM, and SRDOM. The pigment in IOM contributed to a triplet state pool with strong energy-transfer but limited electron-transfer capabilities. Notably, IOM exhibited the highest triplets state quantum yield value in the visible region, suggesting its potential significance in pollutant degradation in deeper water layers. For EOM, one of the pools exhibits photolability and remarkable electron-transfer capability, indicating it as a high-energy triplet state component. Moreover, three cyanotoxins (MC-LR, ACA, and ATX-a) were detected in the extracted AOM, and their photodegradation was monitored during the AOM photobleaching process. This highlights the potential role of AOM as a photosensitizer in the natural self-cleaning mechanisms of water bodies, facilitating the degradation of organic pollutants through photochemical reactions. The findings of this study contribute to understanding the dynamic nature of AOM and its implications in environmental processes.
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Affiliation(s)
- Shengquan Kong
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Xiaojing Liu
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Hongyu Jiang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Wenjie Hong
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Jibiao Zhang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China.
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6
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Wei B, Li L, Xie X, Qi K, Wang Y, Wang Z. Effect of adsorption on ferrihydrite on the photoreactivity of dissolved black carbon for photodegradation of sulfadiazine. CHEMOSPHERE 2023:139359. [PMID: 37379979 DOI: 10.1016/j.chemosphere.2023.139359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/30/2023] [Accepted: 06/25/2023] [Indexed: 06/30/2023]
Abstract
The selective adsorption of dissolved black carbon (DBC) on inorganic minerals is a widespread geochemical process in the natural environment, which could change the chemical and optical properties of DBC. However, it remains unclear how selective adsorption affects the photoreactivity of DBC for photodegradation of organic pollutants. This paper was the first to investigate the effect of DBC adsorption on ferrihydrite at different Fe/C molar ratios (Fe/C molar ratios of 0, 7.50 and 11.25, and marked as DBC0, DBC7.50 and DBC11.25) on the photoproduction of reactive intermediates generated from DBC and their interaction with sulfadiazine (SD). Results showed that UV absorbance, aromaticity, molecular weight and contents of phenolic antioxidants of DBC were significantly decreased after adsorption on ferrihydrite, and higher decrease was observed at higher Fe/C ratio. Photodegradation kinetics experiments showed that observed photodegradation rate constant of SD (kobs) increased from 3.99 × 10-5 s-1 in DBC0 to 5.69 × 10-5 s-1 in DBC7.50 while decreased to 3.44 × 10-5 s-1 in DBC11.25, in which 3DBC* played important roles and 1O2 played a minor role, while ·OH was not involved in the reaction. Meanwhile, the second-order reaction rate constant between 3DBC* and SD (kSD, 3DBC*) increased from 0.84 × 108 M-1 s-1 for DBC0 to 2.53 × 108 M-1 s-1 for DBC7.50 while decreased to 0.90 × 108 M-1 s-1 for DBC11.25. The above results might be mainly attributed to the fact that the decrease of phenolic antioxidants in DBC weakened the back-reduction of 3DBC* and reactive intermediates of SD as the Fe/C ratio increased, while the decrease of quinones and ketones reduced the photoproduction of 3DBC*. The research revealed adsorption on ferrihydrite affected the photodegradation of SD by changing the reactivity of 3DBC*, which was helpful to understand the dynamic roles of DBC in the photodegradation of organic pollutants.
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Affiliation(s)
- Bin Wei
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Liangyu Li
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xiaoyun Xie
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
| | - Kemin Qi
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yaodong Wang
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Zhaowei Wang
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
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7
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Fu Y, Yan Y, Wei Z, Spinney R, Dionysiou DD, Vione D, Liu M, Xiao R. Overlooked Transformation of Nitrated Polycyclic Aromatic Hydrocarbons in Natural Waters: Role of Self-Photosensitization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37327199 DOI: 10.1021/acs.est.3c02276] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Photochemical transformation is an important process that involves trace organic contaminants (TrOCs) in sunlit surface waters. However, the environmental implications of their self-photosensitization pathway have been largely overlooked. Here, we selected 1-nitronaphthalene (1NN), a representative nitrated polycyclic aromatic hydrocarbon, to study the self-photosensitization process. We investigated the excited-state properties and relaxation kinetics of 1NN after sunlight absorption. The intrinsic decay rate constants of triplet (31NN*) and singlet (11NN*) excited states were estimated to be 1.5 × 106 and 2.5 × 108 s-1, respectively. Our results provided quantitative evidence for the environmental relevance of 31NN* in waters. Possible reactions of 31NN* with various water components were evaluated. With the reduction and oxidation potentials of -0.37 and 1.95 V, 31NN* can be either oxidized or reduced by dissolved organic matter isolates and surrogates. We also showed that hydroxyl (•OH) and sulfate (SO4•-) radicals can be generated via the 31NN*-induced oxidation of inorganic ions (OH- and SO42-, respectively). We further investigated the reaction kinetics of 31NN* and OH- forming •OH, an important photoinduced reactive intermediate, through complementary experimental and theoretical approaches. The rate constants for the reactions of 31NN* with OH- and 1NN with •OH were determined to be 4.22 × 107 and 3.95 ± 0.01 × 109 M-1 s-1, respectively. These findings yield new insights into self-photosensitization as a pathway for TrOC attenuation and provide more mechanistic details into their environmental fate.
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Affiliation(s)
- Yifu Fu
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Yiqi Yan
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Zongsu Wei
- Centre for Water Technology (WATEC) & Department of Engineering, Aarhus University, Hangøvej 2, Aarhus N DK-8200, Denmark
| | - Richard Spinney
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Davide Vione
- Department of Chemistry, University of Turin, Via Pietro Giuria 5, Torino 10125, Italy
| | - Min Liu
- State Key Laboratory of Powder Metallurgy, School of Physics and Electronics, Central South University, Changsha 410083, China
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China
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8
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Tan M, Shi W, Wang H, Di G, Xie Z, Fan S, Tang J, Dong F. Effective photodegradation of antibiotics by guest-host synergy between photosensitizer and bismuth vanadate: Underlying mechanism and toxicity assessment. CHEMOSPHERE 2023; 325:138362. [PMID: 36905996 DOI: 10.1016/j.chemosphere.2023.138362] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/15/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
The removal of antibiotics in wastewater has attracted increasing attention. Herein, a superior photosensitized photocatalytic system was developed with acetophenone (ACP) as the guest photosensitizer, bismuth vanadate (BiVO4) as the host catalyst and poly dimethyl diallyl ammonium chloride (PDDA) as the bridging complex, and used for the removal of sulfamerazine (SMR), sulfadiazine (SDZ) and sulfamethazine (SMZ) in water under simulated visible light (λ > 420 nm). The obtained ACP-PDDA-BiVO4 nanoplates attained a removal efficiency of 88.9%-98.2% for SMR, SDZ and SMZ after 60 min reaction and achieved kinetic rate constant approximately 10, 4.7 and 13 times of BiVO4, PDDA-BiVO4 and ACP-BiVO4, respectively, for SMZ degradation. In the guest-host photocatalytic system, ACP photosensitizer was found to have a great superiority in enhancing the light absorption, promoting the surface charge separation-transfer and efficient generation of holes (h+) and superoxide radical (·O2-), greatly contributing to the photoactivity. The SMZ degradation pathways were proposed based on the identified degradation intermediates, involving three main pathways of rearrangement, desulfonation and oxidation. The toxicity of intermediates was evaluated and the results demonstrated that the overall toxicity was reduced compared with parent SMZ. This catalyst maintained 92% photocatalytic oxidation performance after five cyclic experiments and displayed a co-photodegradation ability to others antibiotics (e.g., roxithromycin, ciprofloxacin et al.) in effluent water. Therefore, this work provides a facile photosensitized strategy for developing guest-host photocatalysts, which enabling the simultaneous antibiotics removal and effectively reduce the ecological risks in wastewater.
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Affiliation(s)
- Meihong Tan
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Wanping Shi
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Haifeng Wang
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Guanglan Di
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Zhengxin Xie
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Shisuo Fan
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Jun Tang
- School of Resource and Environment, Anhui Agricultural University, Hefei, 230036, China.
| | - Fengshou Dong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, PR China
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9
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Jiang W, Ma L, Niedek C, Anastasio C, Zhang Q. Chemical and Light-Absorption Properties of Water-Soluble Organic Aerosols in Northern California and Photooxidant Production by Brown Carbon Components. ACS EARTH & SPACE CHEMISTRY 2023; 7:1107-1119. [PMID: 37223426 PMCID: PMC10202033 DOI: 10.1021/acsearthspacechem.3c00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/14/2023] [Accepted: 04/17/2023] [Indexed: 05/25/2023]
Abstract
Atmospheric brown carbon (BrC) can impact the radiative balance of the earth and form photooxidants. However, the light absorption and photochemical properties of BrC from different sources remain poorly understood. To address this gap, dilute water extracts of particulate matter (PM) samples collected at Davis, CA over one year were analyzed using high resolution aerosol mass spectrometry (HR-AMS) and UV-vis spectroscopy. Positive matrix factorization (PMF) on combined AMS and UV-vis data resolved five water-soluble organic aerosol (WSOA) factors with distinct mass spectra and UV-vis spectra: a fresh and an aged water-soluble biomass burning OA (WSBBOAfresh and WSBBOAaged) and three oxygenated OA (WSOOAs). WSBBOAfresh is the most light-absorbing, with a mass absorption coefficient (MAC365 nm) of 1.1 m2 g-1, while the WSOOAs are the least (MAC365 nm = 0.01-0.1 m2 g-1). These results, together with the high abundance of WSBBOAs (∼52% of the WSOA mass), indicate that biomass burning activities such as residential wood burning and wildfires are an important source of BrC in northern California. The concentrations of aqueous-phase photooxidants, i.e., hydroxyl radical (·OH), singlet molecular oxygen (1O2*), and oxidizing triplet excited states of organic carbon (3C*), were also measured in the PM extracts during illumination. Oxidant production potentials (PPOX) of the five WSOA factors were explored. The photoexcitation of BrC chromophores from BB emissions and in OOAs is a significant source of 1O2* and 3C*. By applying our PPOX values to archived AMS data at dozens of sites, we found that oxygenated organic species play an important role in photooxidant formation in atmospheric waters.
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Affiliation(s)
- Wenqing Jiang
- Department
of Environmental Toxicology, University
of California, 1 Shields Avenue, Davis, California 95616, United States
- Agricultural
and Environmental Chemistry Graduate Program, University of California, 1 Shields Avenue, Davis, California 95616, United States
| | - Lan Ma
- Agricultural
and Environmental Chemistry Graduate Program, University of California, 1 Shields Avenue, Davis, California 95616, United States
- Department
of Land, Air, and Water Resources, University
of California, 1 Shields
Avenue, Davis, California 95616, United States
| | - Christopher Niedek
- Department
of Environmental Toxicology, University
of California, 1 Shields Avenue, Davis, California 95616, United States
- Agricultural
and Environmental Chemistry Graduate Program, University of California, 1 Shields Avenue, Davis, California 95616, United States
| | - Cort Anastasio
- Agricultural
and Environmental Chemistry Graduate Program, University of California, 1 Shields Avenue, Davis, California 95616, United States
- Department
of Land, Air, and Water Resources, University
of California, 1 Shields
Avenue, Davis, California 95616, United States
| | - Qi Zhang
- Department
of Environmental Toxicology, University
of California, 1 Shields Avenue, Davis, California 95616, United States
- Agricultural
and Environmental Chemistry Graduate Program, University of California, 1 Shields Avenue, Davis, California 95616, United States
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10
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Wang H, Zhang T, Ji Y, Lu J. Photodegradation of phenylurea herbicides sensitized by norfloxacin and the influence of natural organic matter. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130135. [PMID: 36303339 DOI: 10.1016/j.jhazmat.2022.130135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/20/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
The photochemical activity of fluoroquinolone antibiotics (FQs) has gained attention due to the discovery of their phototoxicity and photocarcinogenicity in clinics. This study reveals that norfloxacin (NOR) can sensitize the photodegradation of phenylurea (PU) herbicides. This is attributed to the formation of an excited triplet of norfloxacin (3NOR*) by UV-A irradiation of its quinolone chromophore, which can further react with O2 to form singlet oxygen (1O2). The second-order rate of 3NOR* with PU ranges from 1.54 × 1010 to 2.76 × 1010 M-1s-1. The steady-state concentrations of 3NOR* were calculated as (4.29-31.2)× 10-16 M at 10 μM NOR under UV365nm irradiation. Natural organic matter (NOM) inhibited the degradation of PU induced by 3NOR*. In the presence of 10 mg L-1 NOM, the pseudo-first-order rate constants (kobs,NOM) of the degradation of diuron (DIU), isoproturon (IPU), monuron (MOU), and chlorotoluron (CLU) decreased by 65%, 19%, 36%, and 62%, respectively. NOM mainly acts as a reductant which reacted with the radical intermediates of the PU generated by 3NOR*oxidation, thus reversing the oxidation. The inhibitory effect increases with increasing NOM concentration. Results of this study underscore the role of NOR as a photosensitizer in accelerating the abatement of PU pesticides in sunlit surface waters. This study significantly advances the understandings of the behavior of NOR in aquatic environments.
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Affiliation(s)
- Haiyan Wang
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Teng Zhang
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuefei Ji
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Junhe Lu
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China.
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11
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Wenk J, Graf C, Aeschbacher M, Sander M, Canonica S. Effect of Solution pH on the Dual Role of Dissolved Organic Matter in Sensitized Pollutant Photooxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15110-15122. [PMID: 34714642 PMCID: PMC8735754 DOI: 10.1021/acs.est.1c03301] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Dissolved organic matter (DOM) has a dual role in indirect phototransformations of aquatic contaminants by acting both as a photosensitizer and an inhibitor. Herein, the pH dependence of the inhibitory effect of DOM and the underlying mechanisms were studied in more than 400 kinetic irradiation experiments over the pH range of 6-11. Experiments employed various combinations of one of three DOM isolates, one of two model photosensitizers, the model antioxidant phenol, and one of nine target compounds (TCs), comprising several aromatic amines, in particular anilines and sulfonamides, and 4-cyanophenol. Using model photosensitizers without antioxidants, the phototransformation of most TCs increased with increasing pH, even for TCs for which pH did not affect speciation. This trend was attributed to pH-dependent formation yields of TC-derived radicals and their re-formation to the parent TC. Analogous trends were observed with DOM as a photosensitizer. Comparison of model and DOM photosensitizer data sets showed increasing inhibitory effects of DOM on TC phototransformation kinetics with increasing pH. In systems with anilines as a TC and phenol as a model antioxidant, pH trends of the inhibitory effect could be rationalized based on the reduction potential difference (ΔEred) of phenoxyl/phenol and anilinyl/aniline couples. Our results indicate that the light-induced transformation of aromatic amines in the aquatic environment is governed by the pH-dependent inhibitory effects of antioxidant phenolic moieties of DOM and pH-dependent processes related to the formation of amine oxidation intermediates.
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Affiliation(s)
- Jannis Wenk
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
- Department
of Chemical Engineering and Water Innovation & Research Centre
(WIRC), University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- . Tel: +44-1225-383246
| | - Cornelia Graf
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
- INFRAS
Research and Consulting, CH-3012 Berne, Switzerland
| | - Michael Aeschbacher
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Michael Sander
- Institute
of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Silvio Canonica
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
- . Tel: +41-58-765-5453. Fax: +41-58-765-5210
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12
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Lewer J, Huang J, Peloquin J, Kostal J. Structure-Energetics-Property Relationships Support Computational Design of Photodegradable Pesticides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11713-11722. [PMID: 34428037 DOI: 10.1021/acs.est.1c02556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Development of high-performing pesticides with tunable degradation properties is vital to increasing the safety and effectiveness of tomorrow's analogs. Chromophoric dissolved organic matter in the excited triple state (3CDOM*) is known to play a key role in the removal of pesticides via indirect photodegradation. However, the potential of these transformations to guide the design of safer chemicals has not yet been fully realized. Here, we report a two-tier computational framework developed to probe and predict both kinetics and thermodynamics of 3CDOM*-pesticide interactions. In the first tier, robust in silico models were constructed by fitting free energies obtained from density functional theory (DFT) calculations to cell potentials and second-order rate constants for the 3CDOM*-pesticide electron transfer. In the second tier, Gibbs free energies and corresponding free energy barriers, determined in solution using the Marcus theory, were applied to develop a quick yet accurate screening approach based on the frontier molecular orbital (FMO) Theory. Being highly mechanistic and spanning ca. 1500 unique 3CDOM*-pesticide interactions, our approach is both robust and broadly applicable. To that end, the outcomes of our computational models were integrated into an easy-to-use decision framework that can guide structure-based design of less persistent pesticide analogs.
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Affiliation(s)
- Jessica Lewer
- Department of Chemistry, The George Washington University, 800 22nd St NW, Ste 4000, Washington, District of Columbia 20052-0066, United States
| | - Jessica Huang
- Department of Chemistry, The George Washington University, 800 22nd St NW, Ste 4000, Washington, District of Columbia 20052-0066, United States
| | - John Peloquin
- Department of Chemistry, The George Washington University, 800 22nd St NW, Ste 4000, Washington, District of Columbia 20052-0066, United States
| | - Jakub Kostal
- Department of Chemistry, The George Washington University, 800 22nd St NW, Ste 4000, Washington, District of Columbia 20052-0066, United States
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13
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Felber T, Schaefer T, He L, Herrmann H. Aromatic Carbonyl and Nitro Compounds as Photosensitizers and Their Photophysical Properties in the Tropospheric Aqueous Phase. J Phys Chem A 2021; 125:5078-5095. [PMID: 34096724 DOI: 10.1021/acs.jpca.1c03503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Secondary organic aerosol formation in the atmospheric aqueous/particulate phase by photosensitized reactions is currently subject to uncertainties. To understand the impact of photosensitized reactions, photophysical and -chemical properties of photosensitizers, kinetic data, and reaction mechanisms of these processes are required. The photophysical properties of acetophenones, benzaldehydes, benzophenones, and naphthalenes were investigated in aqueous solution using laser flash excitation. Quantum yields of excited photosensitizers were determined giving values between 0.06-0.80 at 298 K and pH = 5. Molar absorption coefficients (εmax(3PS*) = (0.8-13) × 104 L mol-1 cm-1), decay rate constants in water (k1st = (9.4 ± 0.5) × 102 to (2.2 ± 0.1) × 105 s-1), and quenching rate constants with oxygen (kq(O2) = (1.7 ± 0.1-4.4 ± 0.4) × 109 L mol-1 s-1) of the excited triplet states were determined at 298 K and pH = 5. Photosensitized reactions of carboxylic acids and alkenes show second-order rate constants in the range of (37 ± 7.0-0.55 ± 0.1) × 104 and (27 ± 5.0-0.04 ± 0.01) × 108 L mol-1 s-1. The results show that different compound classes act differently as a photosensitizer and can be a sink for certain organic compounds in the atmospheric aqueous phase.
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Affiliation(s)
- Tamara Felber
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Thomas Schaefer
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Lin He
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Hartmut Herrmann
- Leibniz Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany
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14
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Lu J, Ji Y, Chovelon JM, Lu J. Fluoroquinolone antibiotics sensitized photodegradation of isoproturon. WATER RESEARCH 2021; 198:117136. [PMID: 33894578 DOI: 10.1016/j.watres.2021.117136] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Fluoroquinolone (FQ) antibiotics are a group of contaminants of emerging environmental concern. In the present study, we demonstrated that norfloxacin (NORF) and ofloxacin (OFLO), two typical FQs, have photochemical reactivity analogous to chromophoric dissolved natural organic matter (DOM) in surface waters and can sensitize the photodegradation of isoproturon (IPU), a phenylurea herbicide. Such photochemical reactivity is ascribed to the quinolone chromophore that is excited to a triplet state (3FQ*) upon UV-A irradiation. 3FQ* further reacts with dissolved oxygen to give rise to singlet oxygen. 3FQ* steady-state concentrations of 6.72 × 10-15 and 1.27 × 10-15 M were measured in 10 μM NORF and OFLO solutions, respectively, under UV365nm irradiation. The degradation of IPU was due to the reaction with 3FQ*, with bimolecular rate constants of 6.07 × 109 and 1.51 × 1010 for 3NORF* and 3OFLO*, respectively. Intriguingly, NORF and OFLO per se were unstable and photolyzed during UV-A irradiation, but the photochemical reactivities of the solutions were not lost accordingly. High-resolution mass spectrometry analysis revealed that defluorination and piperazine moiety oxidation were the main photolysis pathways, while the core quinolone structure remained intact. Thus, the photolysis products largely inherited the photochemical reactivity of the parent compounds. Since all FQs share the same quinolone structure, similar photochemical reactivity is expected. The presence of FQs in surface water would affect the transformation and fate of coexisting compounds. To the best of our knowledge, this is the first study examining the environmental behavior of FQs as photosensitizers. The findings greatly advance the understandings of the influence of FQs in aquatic environment.
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Affiliation(s)
- Jiaxin Lu
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuefei Ji
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jean-Marc Chovelon
- Université Claude Bernard Lyon 1, CNRS, IRCELYON, F-69626, Villeurbanne, France
| | - Junhe Lu
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China.
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15
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Remke SC, von Gunten U, Canonica S. Enhanced transformation of aquatic organic compounds by long-lived photooxidants (LLPO) produced from dissolved organic matter. WATER RESEARCH 2021; 190:116707. [PMID: 33373945 DOI: 10.1016/j.watres.2020.116707] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 06/12/2023]
Abstract
Dissolved organic matter (DOM) plays a crucial role in the photochemical transformation of organic contaminants in natural aquatic systems. The present study focuses on the characterization of a specific effect previously observed for electron-rich phenols, consisting in an acceleration of the DOM-photosensitized transformation of target compounds at low concentrations (< 1 µM). This effect was hypothesized to be caused by DOM-derived "long-lived" photooxidants (LLPO). Pseudo-first-order rate constants for the transformation of several phenols, anilines, sulfonamide antibiotics and phenylureas photosensitized by Suwannee River fulvic acid were determined under steady-state irradiation using the UVA and visible wavelengths from a medium-pressure mercury lamp. A significant enhancement (by a factor of 2.4 - 16) of the first-order transformation rate constant of various electron-rich target compounds was observed for an initial concentration of 0.1 μM compared to 5 μM . This effect points to a relevant reactivity of these compounds with LLPO. For phenols and anilines the enhancement effect occurred only above certain standard one-electron oxidation potentials. From these data series the standard one-electron reduction potential of LLPO was estimated to be in the range of 1.0 - 1.3 V versus the standard hydrogen electrode. LLPO are proposed to mainly consist of phenoxyl radicals formed by photooxidation of electron-poor phenolic moieties of the DOM. The plausibility of this hypothesis was successfully tested by studying the photosensitized transformation kinetics of 3,4-dimethoxyphenol in aqueous solutions containing a model photosensitizer (2-acetonaphthone) and a model electron-poor phenol (4-cyanophenol) as DOM surrogates.
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Affiliation(s)
- Stephanie C Remke
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), GC A2 454, Station 18, CH-1015 Lausanne, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), GC A2 454, Station 18, CH-1015 Lausanne, Switzerland
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland.
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16
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Wu B, Arnold WA, Ma L. Photolysis of atrazine: Role of triplet dissolved organic matter and limitations of sensitizers and quenchers. WATER RESEARCH 2021; 190:116659. [PMID: 33279742 DOI: 10.1016/j.watres.2020.116659] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/13/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Atrazine, a widely used herbicide, is susceptible to photolysis. The role of triplet excited states of chromophoric dissolved organic matter (3CDOM*) in the photolysis of atrazine, however, is not well understood. The direct photolysis of atrazine under irradiation sources (natural sunlight/environmentally relevant simulated solar light) and its indirect photochemical reactivity with model triplet photosensitizers (benzophenone, 2-acetonaphthone, 3'-methoxy-acetophenone, 4-carboxybenzophenone, rose bengal, methylene blue, and anthraquinone-2-sulphonate) was investigated. The reactivity of the model sensitizers and DOM (Suwannee River natural organic matter, river/lake water, and wastewater effluent), were compared. The direct photolysis quantum yield was determined as 0.0196 mol Einstein-1 in a solar simulator and 0.00437 mol Einstein-1 under natural sunlight. Considerable photosensitization was induced by triplet state (n-π*) model sensitizers, while insignificant effects on atrazine loss were discerned in natural organic matter even when oxygen, a triplet quencher, was removed. The triplet sensitizers benzophenone and 2-acetylnaphthone reacted with L-histidine and 2-propanol that were intended to quench/ scavenge 1O2 and hydroxyl radical •OH, respectively, and benzophenone reacted with NaN3 as a 1O2 scavenger and furfuryl alcohol as a 1O2 trapping agent, indicating quenchers may have unanticipated effects when using model sensitizers. Atrazine loss via reaction with 3DOM* will be relevant only in selected conditions, and this work provides a more comprehensive view on the use of model photosensitizers to mimic triplet 3DOM*.
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Affiliation(s)
- Bin Wu
- School of Environmental Science and Engineering, Tongji University, Shanghai, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Technology, Tongji University, Shanghai, China; Department of Civil, Environmental, and Geo- Engineering, University of Minnesota - Twin Cities, 500 Pillsbury Drive SE, Minneapolis, MN 55455, United States
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota - Twin Cities, 500 Pillsbury Drive SE, Minneapolis, MN 55455, United States
| | - Limin Ma
- School of Environmental Science and Engineering, Tongji University, Shanghai, China.
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17
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Felber T, Schaefer T, Herrmann H. Five-Membered Heterocycles as Potential Photosensitizers in the Tropospheric Aqueous Phase: Photophysical Properties of Imidazole-2-carboxaldehyde, 2-Furaldehyde, and 2-Acetylfuran. J Phys Chem A 2020; 124:10029-10039. [PMID: 33202138 DOI: 10.1021/acs.jpca.0c07028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photosensitized reactions of organic compounds in the atmospheric aqueous and particle phase might be potential sources for secondary organic aerosol (SOA) formation, addressed as aqueous SOA. However, data regarding the photophysical properties of photosensitizers, their kinetics, as well as reaction mechanisms of such processes in the aqueous/particle phase are scarce. The present study investigates the determination of the photophysical properties of imidazole-2-carboxaldehyde, 2-furaldehyde, and 2-acetylfuran as potential photosensitizers using laser flash excitation in aqueous solution. Quantum yields of the formation of the excited photosensitizers were obtained by a scavenging method with thiocyanate, resulting in values between 0.86 and 0.96 at 298 K and pH = 5. The time-resolved absorbance spectra of the excited photosensitizers were measured, and their molar attenuation coefficients were determined ranging between (0.30 and 1.4) × 104 L mol-1 cm-1 at their absorbance maxima (λmax = 335-440 nm). Additionally, the excited photosensitizers are quenched by water and molecular oxygen, resulting in quenching rate constants of k1st = (1.0 ± 0.2-1.8 ± 0.2) × 105 s-1 and kq(O2) = (2.1 ± 0.2-2.7 ± 0.2) × 109 L mol-1 s-1, respectively.
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Affiliation(s)
- Tamara Felber
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Thomas Schaefer
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstrasse 15, 04318 Leipzig, Germany
| | - Hartmut Herrmann
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstrasse 15, 04318 Leipzig, Germany
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18
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Carena L, Vione D. Mapping the Photochemistry of European Mid-Latitudes Rivers: An Assessment of Their Ability to Photodegrade Contaminants. Molecules 2020; 25:molecules25020424. [PMID: 31968645 PMCID: PMC7024250 DOI: 10.3390/molecules25020424] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/09/2020] [Accepted: 01/14/2020] [Indexed: 12/02/2022] Open
Abstract
The abiotic photochemical reactions that take place naturally in sunlit surface waters can degrade many contaminants that pose concern to water bodies for their potentially toxic and long-term effects. This works aims at assessing the ability of European rivers to photoproduce reactive transient intermediates, such as HO• radicals and the excited triplet states of chromophoric dissolved organic matter (3CDOM*), involved in pollutant degradation. A photochemical mapping of the steady-state concentrations of these transients was carried out by means of a suitable modeling tool, in the latitude belt between 40 and 50°N. Such a map allowed for the prediction of the photochemical lifetimes of the phenylurea herbicide isoproturon (mostly undergoing photodegradation upon reaction with HO• and especially 3CDOM*) across different European countries. For some rivers, a more extensive dataset was available spanning the years 1990–2002, which allowed for the computation of the steady-state concentration of the carbonate radicals (CO3•−). With these data, it was possible to assess the time trends of the photochemical half-lives of further contaminants (atrazine, ibuprofen, carbamazepine, and clofibric acid). The calculated lifetimes were in the range of days to weeks, which might or might not allow for efficient depollution depending on the river-water flow velocity.
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19
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Tian Y, Wei L, Yin Z, Feng L, Zhang L, Liu Y, Zhang L. Photosensitization mechanism of algogenic extracellular organic matters (EOMs) in the photo-transformation of chlortetracycline: Role of chemical constituents and structure. WATER RESEARCH 2019; 164:114940. [PMID: 31401329 DOI: 10.1016/j.watres.2019.114940] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
The ubiquitous algogenic extracellular organic matters (EOMs) could enhance solar photodegradation of antibiotics such as Chlortetracycline (CTC), however, the role of chemical constituents and structure in their photosensitizing process was not clear. In this paper, EOMs were extracted from chlorella vulgaris (CV-EOMs), scenedesmus meyen (SM-EOMs) and microcystis aeruginosa (MA-EOMs) to explore their photosensitive efficiencies and mechanisms. All of the EOMs showed higher photosensitive efficiencies than natural organic matter (NOM). The quenching assays and competitive kinetics experiments confirmed the dominant role of 3EOMs* in accelerating CTC photodegradation. The quantum yield coefficients of 3EOMs* (fTMP) of CV-EOMs, SM-EOMs, MA-EOMs, NOM were 139.89 ± 5.46, 125.35 ± 4.69, 91.76 ± 3.53, and 72.84 ± 4.45 L/(mol-photon), respectively. Specific chemical constituents and structure of EOMs were characterized by nuclear magnetic resonance (NMR), fourier transform ion cyclotron resonance mass spectrometry (FT-CIR-MS) and X-ray photoelectron spectroscopy (XPS). The results showed the positive linear correlation of fTMP with content of carbonyl groups in EOMs. In addition, reduction of carbonyl groups in EOMs by NaBH4 significantly decreased CTC photodegradation rate. Density Functional Theory (DFT) calculation suggested the susceptible excitation of carbonyl groups in EOMs under solar light was ascribed to the lowest required energy of electronic transition from HOMO to LUMO (assigned as n-π* transition). The energy of triplet excited-states benzophenone, p-methoxy acetophenone and acetophenone (the EOMs model compounds) was calculated to be 284.92, 288.85 and 265.50 kJ/mol, which were higher than that of CTC (i.e., 217.46 kJ/mol), indicating the energy transfer from excited triplet state to excited triplet state CTC was possible. This study provided mechanism insights into photosensitization effects of allogenic EOMs on photochemical fate of pollutants in aqueous environment.
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Affiliation(s)
- Yajun Tian
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Lianxue Wei
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Ze Yin
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Lirong Zhang
- Chinese Academy of Environment Planning, Beijing, 100012, China
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
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20
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Canonica S, Schönenberger U. Inhibitory Effect of Dissolved Organic Matter on the Transformation of Selected Anilines and Sulfonamide Antibiotics Induced by the Sulfate Radical. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11783-11791. [PMID: 31517485 DOI: 10.1021/acs.est.9b04105] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dissolved organic matter (DOM) has been shown to inhibit the oxidation of aromatic amines initiated by excited triplet states, an effect that was attributed to the reduction of oxidation intermediates back to their parent compounds. The present study focuses on the quantification of an analogous inhibitory effect of DOM on aqueous oxidations induced by the sulfate radical (SO4·-). Second-order rate constants for the SO4·--induced transformation of selected anilines and sulfonamide antibiotics were determined by competition kinetics in the presence and absence of DOM from three different isolates at pH 8. In the presence of 1 mgC L-1 of DOM, a significant reduction in the rate constant was observed for most of the compounds compared to DOM-free solutions, but for two electron-rich anilines, increases in the rate constant were measured. For 4-cyanoaniline and sulfamethoxazole, the DOM concentration dependence of the rate constant consisted of a sharp decrease up to ∼1.0 mgC L-1 of DOM followed by a region of slight changes or even increases for higher DOM concentrations (up to 5 mgC L-1). This behavior was attributed to the occurrence of the aforementioned inhibitory effect and a counteracting accelerated transformation of the contaminants due to reactions with secondary radical oxidants resulting from DOM oxidation by SO4·-. Both effects of inhibition and secondary oxidants should be considered when assessing the abatement of aromatic amines in SO4·--based advanced oxidation processes.
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Affiliation(s)
- Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133 , CH-8600 Dübendorf , Switzerland
| | - Ursula Schönenberger
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133 , CH-8600 Dübendorf , Switzerland
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21
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Ossola R, Schmitt M, Erickson PR, McNeill K. Furan Carboxamides as Model Compounds To Study the Competition between Two Modes of Indirect Photochemistry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9594-9603. [PMID: 31335132 DOI: 10.1021/acs.est.9b02895] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Singlet oxygen (1O2) and triplet chromophoric dissolved organic matter (3CDOM*) are photochemically produced reactive intermediates responsible for the photodegradation of several micropollutants in the sunlit surface waters. However, elucidating the mechanism of reactions involving both 1O2 and 3CDOM* can be complicated by the deeply interconnected nature of these two reactive species. In this work, we synthesized a series of model compounds inspired by the chemical structure of fenfuram, a fungicide used in the 1980s, and used them to investigate structure-reactivity relationships in photodegradation reactions involving 1O2 and 3CDOM*. A combination of steady-state and time-resolved approaches was employed to successfully predict the extent of 1O2-induced degradation. Conversely, the prediction of triplet-induced reactivity was complicated by the presence of repair mechanisms whose extent and relative importance were difficult to predict. The results of our work indicate that bimolecular rate constants measured via time-resolved techniques alone are not sufficient to accurately predict environmental half-lives, as intrinsic differences in the reaction mechanism can amplify the importance of secondary degradation pathways.
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Affiliation(s)
- Rachele Ossola
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Markus Schmitt
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Paul R Erickson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
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Schmitt M, Moor KJ, Erickson PR, McNeill K. Sorbic Acid as a Triplet Probe: Reactivity of Oxidizing Triplets in Dissolved Organic Matter by Direct Observation of Aromatic Amine Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8087-8096. [PMID: 31269391 DOI: 10.1021/acs.est.9b01789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sorbic acid (2,4-hexadienoic acid; HDA) isomerization is frequently used to probe triplet-state dissolved organic matter (3CDOM*) reactivity, but there remain open questions about the reaction kinetics of 3CDOM* with HDA due to the difficulties of directly measuring 3CDOM* quenching rate constants. Using our recently developed approach based on observing the radical cation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) formed through oxidation of TMPD by 3CDOM*, we studied 3CDOM* quenching kinetics with HDA monitored via transient absorption spectroscopy. A competition kinetics-based approach utilizing formation yields of TMPD•+ was developed, validated with model sensitizers, and used to determine bimolecular rate constants between 3CDOM* oxidants and HDA for diverse DOM isolates and natural waters samples, yielding values in the range of (2.4-7.7) × 108 M-1 s-1. The unquenchable fraction of TMPD-oxidizing triplets showed that, on average, 41% of 3CDOM* oxidants cannot be quenched by HDA. Conversely, cycloheptatriene quenched nearly all TMPD•+-forming triplets in CDOM, suggesting that most 3CDOM* oxidants possess energies greater than 150 kJ mol-1. Comparing results with our companion study, we found slight, but noticeable differences in the 3CDOM* quenching rate constants by HDA and unquenchable triplet fractions determined by oxidation of TMPD and energy transfer to O2 (1O2 formation) methods.
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Affiliation(s)
- Markus Schmitt
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Kyle J Moor
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Paul R Erickson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science , ETH Zurich , 8092 Zurich , Switzerland
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Zhou C, Zhou Q, Zhang X. Transformation of acetaminophen in natural surface water and the change of aquatic microbes. WATER RESEARCH 2019; 148:133-141. [PMID: 30359943 DOI: 10.1016/j.watres.2018.10.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/07/2018] [Accepted: 10/13/2018] [Indexed: 06/08/2023]
Abstract
The kinetics and transformation pathway of acetaminophen (APAP) in natural surface water (one sample from the Yangtze River and three others from different lakes), and the changes of aquatic microbes in surface water were revealed in this study. Both photochemical and microbial reactions contributed to the transformation of APAP under irradiance of 1.0-250 mW/cm2. Microbial compositions were significantly different among surface water, and same microbial transformation product (1,4-bezoquinone) was detected as the predominant biotransformation intermediate in four studied surface water, but the lag phase (12-50-h) for the transformation was highly dependent on the aquatic microbial abundance and composition. The lag phase no longer existed with irradiance increased to 5.9 mW/cm2. Aquatic microbial abundance and composition were influenced by the presence of APAP and radiation, and the influence extent was dependent on microbial species. The findings demonstrated that the individual contribution of biotic and abiotic process to the overall transformation of APAP and maybe other phenol in surface water varied as the background composition of surface water and the external environment changed, and biotransformation dominated (>73%) the overall transformation of APAP in surface water.
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Affiliation(s)
- Chi Zhou
- Hubei Water Resources Research Institute, Wuhan, 430070, PR China; School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China
| | - Qing Zhou
- School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China
| | - Xu Zhang
- School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China.
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24
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Wang J, Chen J, Qiao X, Wang Y, Cai X, Zhou C, Zhang Y, Ding G. DOM from mariculture ponds exhibits higher reactivity on photodegradation of sulfonamide antibiotics than from offshore seawaters. WATER RESEARCH 2018; 144:365-372. [PMID: 30053627 DOI: 10.1016/j.watres.2018.07.043] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 07/14/2018] [Accepted: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Mariculture activities and river inputs lead to coastal seawaters with DOM levels that are comparable to or even higher than those in terrestrial water bodies. However, effects of seawater DOM, and especially of DOM occurring in areas impacted by mariculture, on photodegradation of organic micropollutants, are largely unknown. In this study, simulated sunlight irradiation experiments were performed to probe the effects of DOM extracted from mariculture impacted seawaters and from offshore areas, on photodegradation of three sulfonamide antibiotics (SAs). Results show that the SAs are transformed mainly by indirect photodegradation induced by triplet excited DOM (3DOM*). Compared with DOM from the more pristine coastal waters, the DOM from mariculture impacted areas undergoes less photobleaching, contains higher percentage of humic-like materials and higher proportions of aromatic and carbonyl structures. Thus, the DOM from mariculture areas exhibits higher rates of light absorption, higher formation quantum yields of 3DOM*, higher 3DOM* steady-state concentrations and higher reactivity on photodegradation of the SAs. Photochemistry of the seawater DOM is different from that reported for freshwater lake DOM. This study highlights the importance of probing the effects of DOM from coastal seawaters on photodegradation of organic micropollutants since coastal seawaters are sinks of many aquatic pollutants.
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Affiliation(s)
- Jieqiong Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China.
| | - Xianliang Qiao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China
| | - Yan Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China
| | - Xiyun Cai
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China
| | - Chengzhi Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China
| | - Yaoling Zhang
- Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China
| | - Guanghui Ding
- College of Environmental Science and Engineering, Dalian Maritime University, Linghai Road 1, Dalian 116026, China
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Zhou Z, Chen B, Qu X, Fu H, Zhu D. Dissolved Black Carbon as an Efficient Sensitizer in the Photochemical Transformation of 17β-Estradiol in Aqueous Solution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10391-10399. [PMID: 30130961 DOI: 10.1021/acs.est.8b01928] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dissolved black carbon (DBC) is an important component of the dissolved organic matter (DOM) pool. Nonetheless, little is known about its role in the photochemical processes of organic contaminants. This study investigated the effect of DBC on the phototransformation of 17β-estradiol in aqueous solutions under simulated sunlight. Four well-studied dissolved humic substances (DHS) were included as comparisons. DBC acted as a very effective sensitizer to facilitate the phototransformation of 17β-estradiol. The apparent quantum yield for 17β-estradiol phototransformation mediated by DBC was approximately six times higher than that by DHS at the same carbon concentration. Quenching experiments suggested that direct reaction with triplet-excited state DBC (3DBC*) was the predominant pathway of 17β-estradiol phototransformation. The higher mediation efficiency of DBC than DHS is likely due to the higher contents of aromatic groups and smaller molecular sizes, which facilitated the generation of 3DBC*. The apparent quantum yield of triplet-excited states production for DBC was 4-8 times higher than that for DHS. The results suggest that 3DBC* may have a considerable contribution to the overall photoreactivity of triplet-excited state DOM in aquatic systems. Our findings also imply that DBC can play an important role in the phototransformation of organic contaminants in the environments.
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Affiliation(s)
- Zhicheng Zhou
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Beining Chen
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Heyun Fu
- State Key Laboratory of Pollution Control and Resource Reuse/School of the Environment , Nanjing University , Nanjing , Jiangsu 210046 , China
| | - Dongqiang Zhu
- School of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
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26
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Berto S, Carena L, Chiavazza E, Marletti M, Fin A, Giacomino A, Malandrino M, Barolo C, Prenesti E, Vione D. Off-line and real-time monitoring of acetaminophen photodegradation by an electrochemical sensor. CHEMOSPHERE 2018; 204:556-562. [PMID: 29602587 DOI: 10.1016/j.chemosphere.2018.03.069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/09/2018] [Accepted: 03/10/2018] [Indexed: 06/08/2023]
Abstract
The photochemistry of N-acetyl-para-aminophenol (acetaminophen, APAP) is here investigated by using differential pulse voltammetry (DPV) analysis to monitor APAP photodegradation upon steady-state irradiation. The purpose of this work is to assess the applicability of DPV to monitor the photochemical behaviour of xenobiotics, along with the development of an electrochemical set-up for the real-time monitoring of APAP photodegradation. We here investigated the APAP photoreactivity towards the main photogenerated reactive transients species occurring in sunlit surface waters (hydroxyl radical HO, carbonate radical CO3-, excited triplet state of anthraquinone-2-sulfonate used as proxy of the chromophoric DOM, and singlet oxygen 1O2), and determined relevant kinetic parameters. A standard procedure based on UV detection coupled with liquid chromatography (HPLC-UV) was used under identical experimental conditions to compare and verify the DPV-based results. The latter were in agreement with HPLC data, with the exception of the triplet-sensitized processes. In the other cases, DPV could be used as an alternative to the well-tested but more costly and time-consuming HPLC-UV technique. We have also assessed the reaction rate constant between APAP and HO by real-time DPV, which allowed for the monitoring of APAP photodegradation inside the irradiation chamber. Unfortunately, real-time DPV measurements are likely to be affected by temperature variations of the irradiated samples. Overall, DPV appeared as a fast, cheap and reasonably reliable technique when used for the off-line monitoring of APAP photodegradation. When a suitable real-time procedure is developed, it could become a very straightforward method to study the photochemical behaviour of electroactive xenobiotics.
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Affiliation(s)
- Silvia Berto
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy.
| | - Luca Carena
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy.
| | - Enrico Chiavazza
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
| | - Matteo Marletti
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
| | - Andrea Fin
- Dept. of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0358, United States
| | - Agnese Giacomino
- Dept. of Drug Science and Technology, University of Torino, Via P. Giuria 9, 10125 Turin, Italy
| | - Mery Malandrino
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
| | - Claudia Barolo
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy; INSTM and NIS Centre, University of Torino, Via Quarello 15A, 10135 Turin, Italy
| | - Enrico Prenesti
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
| | - Davide Vione
- Dept. of Chemistry, University of Torino, Via P. Giuria 7, 10125 Turin, Italy
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27
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Minella M, Rapa L, Carena L, Pazzi M, Maurino V, Minero C, Brigante M, Vione D. An experimental methodology to measure the reaction rate constants of processes sensitised by the triplet state of 4-carboxybenzophenone as a proxy of the triplet states of chromophoric dissolved organic matter, under steady-state irradiation conditions. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2018; 20:1007-1019. [PMID: 29876570 DOI: 10.1039/c8em00155c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
By a combination of transient absorption spectroscopy and steady-state irradiation experiments, we investigated the transformation of phenol and furfuryl alcohol (FFA) sensitised by irradiated 4-carboxybenzophenone (CBBP). The latter is a reasonable proxy molecule to assess the reactivity of the excited triplet states of the chromophoric dissolved organic matter that occurs in natural waters. The main reactive species for the transformation of both phenol and FFA was the CBBP triplet state, despite the fact that FFA is a commonly used probe for 1O2. In the case of FFA it was possible to develop a simple kinetic model that fitted well the experimental data obtained by steady-state irradiation, in a wide range of FFA concentration values. In the case of phenol the model was made much more complex by the likely occurrence of back reactions between radical species (e.g., phenoxyl and superoxide). This problem can be tackled by considering only the experimental data at low phenol concentration, where the degradation rate increases linearly with concentration. We do not recommend the use of 1O2 scavengers/quenchers such as sodium azide to elucidate CBBP photoreaction pathways, because the azide provides misleading results by also acting as a triplet-state quencher. Based on the experimental data, we propose a methodology for the measurement of the CBBP triplet-sensitisation rate constants from steady-state irradiation experiments, allowing for a better assessment of the triplet-sensitised degradation of emerging contaminants.
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Affiliation(s)
- Marco Minella
- Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, 10125 Torino, Italy.
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28
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Yuan Q, Toroz D, Kidley N, Gould IR. Mechanism of Photoinduced Triplet Intermolecular Hydrogen Transfer between Cycloxydim and Chlorothalonil. J Phys Chem A 2018; 122:4285-4293. [PMID: 29659278 DOI: 10.1021/acs.jpca.7b12523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The possible reaction mechanisms for the experimentally observed hydrogen transfer between the herbicide cycloxydim (CD) and the triplet fungicide chlorothalonil (CT) were identified with density functional theory (DFT) and time-dependent density function theory (TDDFT) computations. Excited energy transfer (EET) calculations indicate that reactants for intermolecular hydrogen transfer were formed via energy transfer from triplet CT to ground state CD. Three possible reaction pathways after EET were identified, and hydrogen transfer from the hydroxyl group on the cyclohexane ring of CD to CT exhibited the lowest energy barrier. Natural population analysis (NPA) along the reaction pathways has confirmed that the pathways involved either electron transfer induced proton transfer or coupled electron-proton transfer, leading to different potential energy profiles. Electrostatic potential (ESP) study substantiated the reaction mechanisms in different pathways. This study suggests an explanation for the accelerated photodegradation of CD by CT and provides a pipeline for future studies of photoinduced intermolecular hydrogen transfer.
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Affiliation(s)
- Qi Yuan
- Institute of Chemical Biology, Department of Chemistry , Imperial College , London SW7 2AZ , U.K
| | - Dimitrios Toroz
- Institute of Chemical Biology, Department of Chemistry , Imperial College , London SW7 2AZ , U.K
| | - Nathan Kidley
- Syngenta, Jealott's Hill, Bracknell , Berkshire RG42 6EY , U.K
| | - Ian R Gould
- Institute of Chemical Biology, Department of Chemistry , Imperial College , London SW7 2AZ , U.K
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Kaur R, Anastasio C. First Measurements of Organic Triplet Excited States in Atmospheric Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:5218-5226. [PMID: 29611699 DOI: 10.1021/acs.est.7b06699] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Photooxidants chemically transform organic compounds in atmospheric drops and particles. Photooxidants such as hydroxyl radical (•OH) and singlet molecular oxygen (1O2*) have been characterized in cloud and fog drops, but there are no measurements of the triplet excited states of organic matter (3C*). These "triplets", which are formed from excitation of chromophoric dissolved organic matter (CDOM), i.e., brown carbon, are difficult to measure because they are a mixture of species instead of a single entity. Here, we use a two-probe technique to measure the steady-state concentrations, rates of photoformation, and quantum yields of oxidizing triplet states during simulated-sunlight illumination of bulk fog waters. Concentrations of 3C* are (0.70-15) × 10-14 M with an average (±σ) value of 5.0 (±5.1) × 10-14 M. The average 3C* photoformation rate is 130 (±130) μM h-1, while the average quantum yield is 3.7 (±4.5)%. Based on our previous measurements of •OH and 1O2* in the same fog samples, the ratio of the steady-state concentrations for 1O2*:3C*:•OH is approximately 3:1:0.04, respectively. At our measured concentrations, triplet excited states can be the dominant aqueous oxidants for organic compounds such as phenols from biomass combustion.
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Pan Y, Garg S, Waite TD, Yang X. Copper Inhibition of Triplet-Induced Reactions Involving Natural Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2742-2750. [PMID: 29425033 DOI: 10.1021/acs.est.7b05655] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The triplet excited state of natural organic matter (3NOM*) is an important reactive intermediate in sensitizing transformation of a wide range of environmentally relevant organic compounds, but the impact of trace metals on the fate and reactivity of 3NOM* is poorly understood. In this study, we investigate the effect of low concentrations of copper on 3NOM*-mediated oxidation (electron transfer) and energy transfer reactions. The oxidative efficiency of 3NOM* from Suwannee River NOM (SRNOM) and the widely used model triplet sensitizer 4-carboxybenzophenone were determined by measuring the photooxidation of 2,4,6-trimethylphenol (TMP). The pseudo-first-order photooxidation rate constants of TMP decreased markedly in the presence of trace amounts of Cu(II) (25-500 nM) with the decrease associated with the continuous reduction of the oxidation intermediates of TMP (i.e., TMP•(-H)) by the photochemically produced Cu(I). A kinetic model is developed that adequately describes the Cu inhibition effect in TMP photooxidation in irradiated SRNOM solutions. The 3NOM* energy transfer ability was assessed by measuring the isomerization of sorbic acid with the rate of this process markedly retarded in the presence of significantly higher (micromolar) concentrations of Cu(II) than previously used. This result is attributed to (i) decreased formation of high energy 3NOM* due to formation of Cu-NOM complexes and (ii) increased loss of 3NOM* as a result of quenching by Cu. Since 3NOM* is the precursor to singlet oxygen (1O2) formation, the steady-state concentrations of 1O2 also decreased in the presence of micromolar concentrations of Cu(II) with the quenching rate constant of 3NOM* by Cu calculated to be 1.08 × 1010 M-1 s-1.
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Affiliation(s)
- Yanheng Pan
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology , Sun Yat-sen University , Guangzhou 510275 , China
| | - Shikha Garg
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - T David Waite
- School of Civil and Environmental Engineering , The University of New South Wales , Sydney , New South Wales 2052 , Australia
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology , Sun Yat-sen University , Guangzhou 510275 , China
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31
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Jiang B, Xin S, Liu Y, He H, Li L, Tang Y, Luo S, Bi X. The role of thiocyanate in enhancing the process of sulfite reducing Cr(VI) by inhibiting the formation of reactive oxygen species. JOURNAL OF HAZARDOUS MATERIALS 2018; 343:1-9. [PMID: 28934687 DOI: 10.1016/j.jhazmat.2017.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/03/2017] [Accepted: 09/08/2017] [Indexed: 06/07/2023]
Abstract
The reductive detoxification of Cr(VI) by sulfite is known as the prevailing strategy and can be successfully implemented for the treatment of Cr(VI)-contaminated waters. However, this method inevitably faces the challenges of excessive consumption of sulfite due to the generations of highly oxidative OH and SO4- during the process of sulfite reducing Cr(VI). In this study, we find that a small quantity of thiocyanate (SCN) can catalytically enhance the process efficiency of Cr(VI) reduction by sulfite and effectively prevent the excessive consumption of sulfite. Specifically, when adding 5μM SCN into 100μM Cr(VI) + 600μM sulfite reaction system at pH 3.5, Cr(VI) reduction amount and [sulfite]oxidation/[Cr(VI)]reduction ratio value were approximately 2 and 0.45, respectively, times those in the SCN-free case. The maximum Cr(VI) reduction amount can be achieved at an initial [SCN]/[Cr(VI)] molar ratio of 2.0. Electron spin resonance measurement, combined with the fluorescence spectrum detection, verified that the process of sulfite reducing Cr(VI) mediated by SCN probably proceeds via the non-radical pathway, avoiding the formation of OH and SO4- under aerobic condition.
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Affiliation(s)
- Bo Jiang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China.
| | - Shuaishuai Xin
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Yijie Liu
- School of Science, Qingdao University of Technology, Qingdao 266033, PR China
| | - Haihong He
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Lin Li
- College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, PR China
| | - Yizhen Tang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Siyi Luo
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Xuejun Bi
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
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32
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Lin VS, Grandbois M, McNeill K. Fluorescent Molecular Probes for Detection of One-Electron Oxidants Photochemically Generated by Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9033-9041. [PMID: 28723081 DOI: 10.1021/acs.est.7b02138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report a dual probe system based on 4'-substituted biphenyl-2-carboxylic acids (BPAs) for analysis of photooxidants generated by dissolved organic matter. The BPA probes are converted to the corresponding benzocoumarins (BZCs) at different rates depending on the mechanism of oxidation; thus, two probes used simultaneously can differentiate strong triplet excited state sensitizers from hydroxylating species such as hydroxyl radical (•OH) present in dissolved organic matter (DOM). Comparison of the ratios of BZC-CH3 and BZC-CF3 product formation using model photooxidants such as NaNO2, a •OH precursor, and model triplet sensitizer lumichrome gave a range of 2 to 250. Application of these probes to DOM isolates and whole natural waters afforded intermediate ratios. Although the oxidation potential of BPAs (>ca. 1.80 V SHE) is significantly higher than the estimated average reduction potential of typical 3CDOM* samples, these results have demonstrated the presence of a small pool of oxidants in the selected DOM isolates and whole water samples that is capable of oxidizing aromatic carboxylates. As an analytical tool, this probe pair can be used between pH 4-6 without affecting the product formation ratio and may find applications in various systems involving complex mixtures of photochemically produced oxidants of differing natures.
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Affiliation(s)
- Vivian S Lin
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , CH-8092, Zurich, Switzerland
| | - Matthew Grandbois
- The Dow Chemical Company , 455 Forest Street, Marlborough, Massachusetts 01568, United States
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , CH-8092, Zurich, Switzerland
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33
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Al-Nu'airat J, Altarawneh M, Gao X, Westmoreland PR, Dlugogorski BZ. Reaction of Aniline with Singlet Oxygen (O 21Δ g). J Phys Chem A 2017; 121:3199-3206. [PMID: 28406298 DOI: 10.1021/acs.jpca.7b00765] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dissolved organic matter (DOM) acts as an effective photochemical sensitizer that produces the singlet delta state of molecular oxygen (O21Δg), a powerful oxidizer that removes aniline from aqueous solutions. However, the exact mode of this reaction, the p- to o-iminobenzoquinone ratio, and the selectivity of one over the other remain largely speculative. This contribution resolves these uncertainties. We report, for the first time, a comprehensive mechanistic and kinetic account of the oxidation of aniline with the singlet delta oxygen using B3LYP and M06 functionals in both gas and aqueous phases. Reaction mechanisms have been mapped out at E, H, and G scales. The 1,4-cycloaddition of O21Δg to aniline forms a 1,4-peroxide intermediate (M1), which isomerizes via a closed-shell mechanism to generate a p-iminobenzoquinone molecule. On the other hand, the O21Δg ene-type reaction forms an o-iminobenzoquinone product when the hydroperoxyl bond breaks, splitting hydroxyl from the 1,2-hydroperoxide (M3) moiety. The gas-phase model predicts the formation of both p- and o-iminobenzoquinones. In the latter model, the M1 adduct displays the selectivity of up to 96%. A water-solvation model predicts that M1 decomposes further, forming only p-iminobenzoquinone with a rate constant of k = 1.85 × 109 (L/(mol s)) at T = 313 K. These results corroborate the recent experimental findings of product concentration profile in which p-iminobenzoquinonine represents the only detected product.
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Affiliation(s)
- Jomana Al-Nu'airat
- School of Engineering and Information Technology, Murdoch University , 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Mohammednoor Altarawneh
- School of Engineering and Information Technology, Murdoch University , 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Xiangpeng Gao
- School of Engineering and Information Technology, Murdoch University , 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Phillip R Westmoreland
- Department of Chemical and Biomolecular Engineering, North Carolina State University , Raleigh North Carolina 27695-7905, United States
| | - Bogdan Z Dlugogorski
- School of Engineering and Information Technology, Murdoch University , 90 South Street, Murdoch, Western Australia 6150, Australia
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Rering C, Williams K, Hengel M, Tjeerdema R. Comparison of Direct and Indirect Photolysis in Imazosulfuron Photodegradation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:3103-3108. [PMID: 28368590 DOI: 10.1021/acs.jafc.7b00134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Imazosulfuron, a sulfonylurea herbicide used in rice cultivation, has been shown to undergo photodegradation in water, but neither the photochemical mechanism nor the role of indirect photolysis is known. The purpose of this study was to investigate the underlying processes that operate on imazosulfuron during aqueous photodegradation. Our data indicate that in the presence of oxygen, most photochemical degradation proceeds through a direct singlet-excited state pathway, whereas triplet-excited state imazosulfuron enhanced decay rates under low dissolved oxygen conditions. Oxidation by hydroxyl radical and singlet oxygen were not significant. At dissolved organic matter (DOM) concentrations representative of rice field conditions, fulvic acid solutions exhibited faster degradation than rice field water containing both humic and fulvic acid fractions. Both enhancement, via reaction with triplet-state DOM, and inhibition, via competition for photons, of degradation was observed in DOM solutions.
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Affiliation(s)
- Caitlin Rering
- Center for Medicinal and Veterinary Entomology, U.S. Department of Agriculture , 1600 S.W. 23rd Drive, Gainesville, Florida 32608, United States
| | - Katryn Williams
- Environmental Toxicology Department, University of California-Davis , 4138 Meyer Hall, One Shields Avenue, Davis, California 95616, United States
| | - Matt Hengel
- Environmental Toxicology Department, University of California-Davis , 4138 Meyer Hall, One Shields Avenue, Davis, California 95616, United States
| | - Ronald Tjeerdema
- Environmental Toxicology Department, University of California-Davis , 4138 Meyer Hall, One Shields Avenue, Davis, California 95616, United States
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Zhou H, Lian L, Yan S, Song W. Insights into the photo-induced formation of reactive intermediates from effluent organic matter: The role of chemical constituents. WATER RESEARCH 2017; 112:120-128. [PMID: 28153698 DOI: 10.1016/j.watres.2017.01.048] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/21/2017] [Accepted: 01/23/2017] [Indexed: 05/21/2023]
Abstract
In the present study, the formation of triplet states of organic matters (3OM∗) from effluent organic matter (EfOM) under simulated solar irradiation was investigated. EfOM was separated into hydrophobic (HPO), transphilic (TPI), and hydrophilic (HPI) components. The quantum yield coefficients (ƒTMP) of 3OM∗ were measured for each component and compared to those of reference natural organic matter (NOM). NaBH4 reduction was performed on the EfOM, and the effect of aromatic ketones moieties on triplet formation was also determined. Furthermore, the apparent quantum yield of 1O2 (Φ1O2) and O2•- (ΦO2•-) was measured. Our results suggested that the HPI fraction acted as a sink for 3OM∗. A linear correlation was observed between ƒTMP and Φ1O2 for NOM/EfOM, except for NaBH4-reduced effluent and HPI components. Both ƒTMP and Φ1O2 were positively correlated with the contribution rates of NaBH4-reducible moieties (aromatic ketones) toward 3OM∗. Aromatic ketones were primarily responsible for the production of 3OM∗ from EfOM, whereas quinone moieties played a key role in the production of 3OM∗ in NOM-enriched solutions. Understanding the role of chemical constituents on the photo activity of EfOM/NOM is essential for providing useful insights on their photochemical effects in aquatic systems.
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Affiliation(s)
- Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Lushi Lian
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, PR China.
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36
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Amorati R, Valgimigli L, Viglianisi C, Schmallegger M, Neshchadin D, Gescheidt G. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols to Benzophenone Triplets. Chemistry 2017; 23:5299-5306. [DOI: 10.1002/chem.201605931] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Riccardo Amorati
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Luca Valgimigli
- University of Bologna; Department of Chemistry “G. Ciamician”; Via S. Giacomo 11 40126 Bologna Italy
| | - Caterina Viglianisi
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino Italy
| | - Max Schmallegger
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Dmytro Neshchadin
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Georg Gescheidt
- Institute of Physical and Theoretical Chemistry; Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
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37
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Martin MV, Mignone RA, Rosso JA, David Gara P, Pis Diez R, Borsarelli CD, Mártire DO. Transient spectroscopic characterization and theoretical modeling of fulvic acid radicals formed by UV-A radiation. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2016.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rosario-Ortiz FL, Canonica S. Probe Compounds to Assess the Photochemical Activity of Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12532-12547. [PMID: 27736067 DOI: 10.1021/acs.est.6b02776] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The photochemical properties of dissolved organic matter (DOM) have been of interest to scientists and engineers since the 1970s. Upon light absorption, chromophoric DOM (CDOM) can sensitize the formation of different short-lived reactive intermediates (RIs), including hydroxyl radical (•OH), singlet oxygen (1O2) and superoxide radical anion (O2•-). In addition, a fraction of the excited singlet states in CDOM decays into excited triplet states (3CDOM*), which are also important photochemical transients in environmental systems. These RIs have a significant impact on different processes in sunlit waters, including degradation of organic contaminants and the inactivation of pathogens. Due to their transient nature and low steady-state concentrations, the use of common analytical techniques for the direct measurement of these species is impractical. Therefore, specific probe compounds (PCs) are used. PCs include furfuryl alcohol for 1O2, and terephthalic acid for •OH. In this publication, we present a critical review of the use of PCs for the assessment of the formation of photochemically generated RIs. We first introduce the concept of a PC, including the kinetic treatment and necessary assumptions needed to conduct a specific measurement. Afterward, we present short overviews of the most studied RIs and review relevant issues regarding the use of specific PCs for their measurement. We finalize by offering recommendations regarding the use of PCs in environmental photochemistry.
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Affiliation(s)
- Fernando L Rosario-Ortiz
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 CH-8600, Dübendorf, Switzerland
- Department of Civil, Environmental and Architectural Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133 CH-8600, Dübendorf, Switzerland
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Avetta P, Fabbri D, Minella M, Brigante M, Maurino V, Minero C, Pazzi M, Vione D. Assessing the phototransformation of diclofenac, clofibric acid and naproxen in surface waters: Model predictions and comparison with field data. WATER RESEARCH 2016; 105:383-394. [PMID: 27657658 DOI: 10.1016/j.watres.2016.08.058] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 08/24/2016] [Accepted: 08/27/2016] [Indexed: 05/27/2023]
Abstract
Phototransformation is important for the fate in surface waters of the pharmaceuticals diclofenac (DIC) and naproxen (NAP) and for clofibric acid (CLO), a metabolite of the drug clofibrate. The goal of this paper is to provide an overview of the prevailing photochemical processes, which these compounds undergo in the different conditions found in freshwater environments. The modelled photochemical half-life times of NAP and DIC range from a few days to some months, depending on water conditions (chemistry and depth) and on the season. The model indicates that direct photolysis is the dominant degradation pathway of DIC and NAP in sunlit surface waters, and potentially toxic cyclic amides were detected as intermediates of DIC direct phototransformation. With modelled half-life times in the month-year range, CLO is predicted to be more photostable than DIC or NAP and to be degraded mainly by reaction with the •OH radical and with the triplet states of chromophoric dissolved organic matter (3CDOM*). The CLO intermediates arising from these processes and detected in this study (hydroquinone and 4-chlorophenol) are, respectively, a chronic toxicant to aquatic organisms and a possible carcinogen for humans. Hydroquinone is formed with only ∼5% yield upon CLO triplet-sensitised transformation, but it is highly toxic for algae and crustaceans. In contrast, the formation yield of 4-chlorophenol reaches ∼50% upon triplet sensitisation and ∼10% by ·OH reaction. The comparison of model predictions with field data from a previous study yielded a very good agreement in the case of DIC and, when using 4-carboxybenzophenone as proxy for triplet sensitisation by CDOM, a good agreement was found for CLO as well. In the case of NAP, the comparison with field data suggests that its direct photolysis quantum yield approaches or even falls below the lower range of literature values.
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Affiliation(s)
- Paola Avetta
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Debora Fabbri
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Marco Minella
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Marcello Brigante
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France; CNRS, UMR 6296, ICCF, BP 80026, F-63177 Aubière, France
| | - Valter Maurino
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Claudio Minero
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Marco Pazzi
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1)
| | - Davide Vione
- Università degli Studi di Torino, Dipartimento di Chimica, Via P. Giuria 5, 10125 Torino, Italy(1); Università degli Studi di Torino, Centro Interdipartimentale NatRisk, Via L. Da Vinci 44, 10095 Grugliasco (TO), Italy(2).
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40
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Yuan C, Chakraborty M, Canonica S, Weavers LK, Hadad CM, Chin YP. Isoproturon Reappearance after Photosensitized Degradation in the Presence of Triplet Ketones or Fulvic Acids. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12250-12257. [PMID: 27737542 DOI: 10.1021/acs.est.6b03655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Isoproturon (IPU) is a phenylurea herbicide used to control broad-leaf grasses on grain fields. Photosensitized transformation induced by excited triplet states of dissolved organic matter (3DOM*) has been identified as an important degradation pathway for IPU in sunlit waters, but the reappearance of IPU in the absence of light is observed after the initial photolysis. In this study, we elucidate the kinetics of this photodegradation and dark-reappearance cycling of IPU in the presence of DOM proxies (aromatic ketones and reference fulvic acids). Using mass spectrometry and nuclear magnetic resonance spectroscopic techniques, a semi-stable intermediate (IPUint) was found to be responsible for IPU reversion and was identified as a hydroperoxyl derivative of IPU. IPUint is photogenerated from incorporation of diatomic oxygen to IPU and is subjected to thermolysis whose rate depends on temperature, pH, the presence of DOM, and inorganic ions. These results are important to understand the overall aquatic fate of IPU and structurally similar compounds under diurnal conditions.
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Affiliation(s)
| | | | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
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41
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McNeill K, Canonica S. Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:1381-1399. [PMID: 27722628 DOI: 10.1039/c6em00408c] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Excited triplet states of chromophoric dissolved organic matter (3CDOM*) play a major role among the reactive intermediates produced upon absorption of sunlight by surface waters. After more than two decades of research on the aquatic photochemistry of 3CDOM*, the need for improving the knowledge about the photophysical and photochemical properties of these elusive reactive species remains considerable. This critical review examines the efforts to date to characterize 3CDOM*. Information on 3CDOM* relies mainly on the use of probe compounds because of the difficulties associated with directly observing 3CDOM* using transient spectroscopic methods. Singlet molecular oxygen (1O2), which is a product of the reaction between 3CDOM* and dissolved oxygen, is probably the simplest indicator that can be used to estimate steady-state concentrations of 3CDOM*. There are two major modes of reaction of 3CDOM* with substrates, namely triplet energy transfer or oxidation (via electron transfer, proton-coupled electron transfer or related mechanisms). Organic molecules, including several environmental contaminants, that are susceptible to degradation by these two different reaction modes are reviewed. It is proposed that through the use of appropriate sets of probe compounds and model photosensitizers an improved estimation of the distribution of triplet energies and one-electron reduction potentials of 3CDOM* can be achieved.
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Affiliation(s)
- Kristopher McNeill
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland.
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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42
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Leresche F, von Gunten U, Canonica S. Probing the Photosensitizing and Inhibitory Effects of Dissolved Organic Matter by Using N,N-dimethyl-4-cyanoaniline (DMABN). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10997-11007. [PMID: 27617886 DOI: 10.1021/acs.est.6b02868] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dissolved organic matter (DOM) can act as a photosensitizer and an inhibitor in the phototransformation of several nitrogen-containing organic contaminants in surface waters. The present study was performed to select a probe molecule that is suitable to measure these antagonistic properties of DOM. Out of nine studied nitrogen-containing aromatic compounds, 4-cyanoaniline, N,N-dimethyl-4-cyanoaniline (DMABN), sotalol (a β-blocker) and sulfadiazine (a sulfonamide antibiotic) exhibited a marked photosensitized transformation that could be substantially inhibited by addition of phenol as a model antioxidant. The photosensitized transformation of DMABN, the selected probe compound, was characterized in detail under UV-A and visible irradiation (λ > 320 nm) to avoid direct phototransformation. Low reactivity of DMABN with singlet oxygen was found (second-order rate constant <2 × 107 M-1 s-1). Typically at least 85% of the reactivity of DMABN could be inhibited by DOM or the model antioxidant phenol. The photosensitized transformation of DMABN mainly proceeded (>72%) through demethylation yielding N-methyl-4-cyanoaniline and formaldehyde as primary products. In solutions of standard DOM extracts and their mixtures the phototransformation rate constant of DMABN was shown to vary nonlinearly with the DOM concentration. Model equations describing the dependence of such rate constants on DOM and model antioxidant concentrations were successfully used to fit experimental data.
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Affiliation(s)
- Frank Leresche
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
- School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich , Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
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McKay G, Couch KD, Mezyk SP, Rosario-Ortiz FL. Investigation of the Coupled Effects of Molecular Weight and Charge-Transfer Interactions on the Optical and Photochemical Properties of Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8093-102. [PMID: 27377760 PMCID: PMC8903045 DOI: 10.1021/acs.est.6b02109] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We studied the formation of photochemically produced reactive intermediates (RI) from dissolved organic matter (DOM). Specifically, we focused on the effects of variable molecular weight and chemical reduction on the optical properties of DOM (absorbance and fluorescence) and the formation of singlet oxygen ((1)O2), DOM triplet excited states ((3)DOM*), and the hydroxyl radical ((•)OH). The data are largely evaluated in terms of a charge-transfer (CT) model, but deficiencies in the model to explain the data are pointed out when evident. A total of two sets of samples were studied that were subjected to different treatments; the first set included secondary-treated wastewaters and a wastewater-impacted stream, and the second was a DOM isolate. Treatments included size fractionation and chemical reduction using sodium borohydride. Taken as a whole, the results demonstrate that decreasing molecular weight and borohydride reduction work in opposition regarding quantum efficiencies for (1)O2 and (3)DOM* production but in concert for fluorescence and (•)OH production. The optical and photochemical data provide evidence for a limited role of CT interactions occurring in lower-molecular-weight DOM molecules. In addition, the data suggest that the observed optical and photochemical properties of DOM are a result of multiple populations of chromophores and that their relative contribution is changed by molecular-weight fractionation and borohydride reduction.
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Affiliation(s)
- Garrett McKay
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Corresponding Authors: G.M.: . F.L.R.-O.:
| | - Kylie D. Couch
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemistry and Biochemistry, California State University, Long Beach, California 90840, United States
| | - Stephen P. Mezyk
- Department of Chemistry and Biochemistry, California State University, Long Beach, California 90840, United States
| | - Fernando L. Rosario-Ortiz
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Corresponding Authors: G.M.: . F.L.R.-O.:
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44
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Jiang B, Wang Z. Response to Comment on "Synergetic Transformations of Multiple Pollutants Driven by Cr(VI)-Sulfite Reactions". ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6109-6111. [PMID: 27172104 DOI: 10.1021/acs.est.6b01877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Bo Jiang
- School of Environmental and Municipal Engineering, Qingdao University of Technology , Qingdao 266033, China
| | - Zhaohui Wang
- College of Environmental Science and Engineering, Donghua University , Shanghai, 201620, China
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45
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Souchier M, Casellas C, Ingrand V, Chiron S. Insights into reductive dechlorination of triclocarban in river sediments: Field measurements and in vitro mechanism investigations. CHEMOSPHERE 2016; 144:425-432. [PMID: 26386432 DOI: 10.1016/j.chemosphere.2015.08.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 08/19/2015] [Accepted: 08/29/2015] [Indexed: 06/05/2023]
Abstract
Triclocarban (TCC) reductive dechlorination was investigated using a combination of field and laboratory experiments. Field monitoring revealed that TCC reductive dechlorination in river sediments leads to formation of two isomers of its lesser chlorinated congener namely 3,4'-dichlorocarbanilide and 4,4'-dichlorocarbanilide. Monochlorocarbanilide was not detected in sediments supporting that transformation of dichlorocarbanilide into monochlorocarbanilide is the rate limiting step of TCC dechlorination. In vitro experiments were conducted to study TCC potential reductive dechlorination mechanisms. These experiments demonstrated that 4,4'-dichlorocarbanilide was specifically formed upon a nucleophilic addition reaction under anaerobic conditions. The 3,4'-diclorocarbanilide was formed upon a two steps radical mechanism under aerobic conditions which includes TCC activation by one electron oxidation followed by a nucleophilic substitution reaction with glutathione. In vitro results suggested that strict anaerobic conditions might not be required for TCC reductive dechlorination in the environment. Moreover, in vitro reactions were performed using biomimetic or enzymatic systems supposing that TCC dechlorination might occur through microbial action in situ. Measured dichlorocarbanilide isomers/triclocarban ratios were used to evaluate the relative significance of both dechlorination pathways and the pathway leading to 3,4'-dichlorocarbanilide was found significant in all investigated river sediment samples.
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Affiliation(s)
- Marine Souchier
- Veolia Recherche et Innovation, Chemin de la Digue, BP 76, 78603 Maisons-Laffitte Cedex, France
| | - Claude Casellas
- UMR Hydrosciences 5569, Université Montpellier, 15 Avenue Ch. Flahault, 34093 Montpellier Cedex 5, France
| | - Valérie Ingrand
- Veolia Recherche et Innovation, Chemin de la Digue, BP 76, 78603 Maisons-Laffitte Cedex, France
| | - Serge Chiron
- UMR Hydrosciences 5569, Université Montpellier, 15 Avenue Ch. Flahault, 34093 Montpellier Cedex 5, France.
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46
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Vione D, De Laurentiis E, Berto S, Minero C, Hatipoglu A, Cinar Z. Modeling the photochemical transformation of nitrobenzene under conditions relevant to sunlit surface waters: Reaction pathways and formation of intermediates. CHEMOSPHERE 2016; 145:277-283. [PMID: 26688265 DOI: 10.1016/j.chemosphere.2015.11.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/12/2015] [Indexed: 06/05/2023]
Abstract
Nitrobenzene (NB) would undergo photodegradation in sunlit surface waters, mainly by direct photolysis and triplet-sensitized oxidation, with a secondary role of the *OH reaction. Its photochemical half-life time would range from a few days to a couple of months under fair-weather summertime irradiation, depending on water chemistry and depth. NB phototransformation gives phenol and the three nitrophenol isomers, in different yields depending on the considered pathway. The minor *OH role in degradation would make NB unsuitable as *OH probe in irradiated natural water samples, but the selectivity towards *OH could be increased by monitoring the formation of phenol from NB+*OH. The relevant reaction would proceed through ipso-addition of *OH on the carbon atom bearing the nitro-group, forming a pre-reactive complex that would evolve into a transition state (and then into a radical addition intermediate) with very low activation energy barrier.
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Affiliation(s)
- Davide Vione
- Università degli Studi di Torino, Dipartimento di Chimica, Via P.Giuria 5, 10125, Torino, Italy.
| | - Elisa De Laurentiis
- Università degli Studi di Torino, Dipartimento di Chimica, Via P.Giuria 5, 10125, Torino, Italy
| | - Silvia Berto
- Università degli Studi di Torino, Dipartimento di Chimica, Via P.Giuria 5, 10125, Torino, Italy
| | - Claudio Minero
- Università degli Studi di Torino, Dipartimento di Chimica, Via P.Giuria 5, 10125, Torino, Italy
| | - Arzu Hatipoglu
- Yildiz Technical University, Department of Chemistry, 34220, Istanbul, Turkey
| | - Zekiye Cinar
- Yildiz Technical University, Department of Chemistry, 34220, Istanbul, Turkey
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47
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Karpuzcu ME, McCabe AJ, Arnold WA. Phototransformation of pesticides in prairie potholes: effect of dissolved organic matter in triplet-induced oxidation. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:237-245. [PMID: 26745785 DOI: 10.1039/c5em00374a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Photochemical reactions involving a variety of photosensitizers contribute to the abiotic transformation of pesticides in prairie pothole lakes (PPLs). Despite the fact that triplet excited state dissolved organic matter (DOM) enhances phototransformation of pesticides by acting as a photosensitizer, it may also decrease the overall phototransformation rate through various mechanisms. In this study, the effect of DOM on the phototransformation of four commonly applied pesticides in four different PPL waters was investigated under simulated sunlight using photoexcited benzophenone-4-carboxylate as the oxidant with DOM serving as an anti-oxidant. For atrazine and mesotrione, a decrease in phototransformation rates was observed, while phototransformations of metolachlor and isoproturon were not affected by DOM inhibition. Phototransformation rates and the extent of inhibition/enhancement by DOM varied spatially and temporally across the wetlands studied. Characterization of DOM from the sites and different seasons suggested that the DOM type and variations in the DOM structure are important factors controlling phototransformation rates of pesticides in PPLs.
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Affiliation(s)
- M Ekrem Karpuzcu
- University of Minnesota, Department of Civil, Environmental, and Geo-Engineering, Minneapolis, MN 55455, USA. and Istanbul Technical University, Department of Environmental Engineering, Maslak 34469, Istanbul, Turkey
| | - Andrew J McCabe
- University of Minnesota, Department of Civil, Environmental, and Geo-Engineering, Minneapolis, MN 55455, USA.
| | - William A Arnold
- University of Minnesota, Department of Civil, Environmental, and Geo-Engineering, Minneapolis, MN 55455, USA.
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48
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Barsotti F, Brigante M, Sarakha M, Maurino V, Minero C, Vione D. Photochemical processes induced by the irradiation of 4-hydroxybenzophenone in different solvents. Photochem Photobiol Sci 2016; 14:2087-96. [PMID: 26463252 DOI: 10.1039/c5pp00214a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The singlet and triplet excited states of 4-hydroxybenzophenone (4BPOH) undergo deprotonation in the presence of water to produce the anionic ground-state, causing fluorescence quenching and photoactivity inhibition. The same process does not take place in an aprotic solvent such as acetonitrile. In acetonitrile, 4BPOH is fluorescent (interestingly, one of its fluorescence peaks overlaps with peak C of humic substances), it yields singlet oxygen upon irradiation and induces the triplet-sensitised transformation of phenol (with a rate constant of (6.6 ± 0.3) × 10(7) M(-1) s(-1) (μ ± σ) between phenol itself and a triplet 4BPOH). The 4BPOH shows an intermediate behaviour in a partially protic solvent such as 2-propanol, where some deprotonation of the excited states is observed. In acetonitrile/2-propanol mixtures (at least up to 50% of 2-propanol) there is also some evidence of alcohol oxidation by the 4BPOH triplet state, while the experimental data are silent concerning such a possibility in pure 2-propanol. Considering that benzophenones are important components of chromophoric dissolved organic matter (CDOM) in surface waters, the present findings could have significance for the photoactivity of the hydrophilic surface layers vs. the hydrophobic cores of CDOM.
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Affiliation(s)
- Francesco Barsotti
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy
| | - Marcello Brigante
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France
| | - Mohamed Sarakha
- Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France
| | - Valter Maurino
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy
| | - Claudio Minero
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy
| | - Davide Vione
- Dipartimento di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy and Centro NatRisk, Via L. Da Vinci 44, 10095 Grugliasco (TO), Italy.
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49
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Calza P, Vione D, Galli F, Fabbri D, Dal Bello F, Medana C. Study of the photochemical transformation of 2-ethylhexyl 4-(dimethylamino)benzoate (OD-PABA) under conditions relevant to surface waters. WATER RESEARCH 2016; 88:235-244. [PMID: 26512801 DOI: 10.1016/j.watres.2015.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/15/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
We studied the aquatic environmental fate of 2-ethylhexyl 4-(dimethylamino)benzoate (OD-PABA), a widespread sunscreen, to assess its environmental persistence and photoinduced transformation. Direct photolysis is shown to play a key role in phototransformation, and this fast process is expected to be the main attenuation route of OD-PABA in sunlit surface waters. The generation of transformation products (TPs) was followed via HPLC/HRMS. Five (or four) TPs were detected in the samples exposed to UVB (or UVA) radiation, respectively. The main detected TPs of OD-PABA, at least as far as HPLC-HRMS peak areas are concerned, would involve a dealkylation or hydroxylation/oxidation process in both direct photolysis and indirect phototransformation. The latter was simulated by using TiO2-based heterogeneous photocatalysis, involving the formation of nine additional TPs. Most of them resulted from the further degradation of the primary TPs that can also be formed by direct photolysis. Therefore, these secondary TPs might also occur as later transformation intermediates in natural aquatic systems.
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Affiliation(s)
- P Calza
- Department of Chemistry, University of Torino, Via P. Giuria 5, 10125, Torino, Italy
| | - D Vione
- Department of Chemistry, University of Torino, Via P. Giuria 5, 10125, Torino, Italy; NatRisk Inter-Department Centre, University of Torino, Via L. da Vinci 44, 10095, Grugliasco (TO), Italy.
| | - F Galli
- Department of Chemistry, University of Torino, Via P. Giuria 5, 10125, Torino, Italy
| | - D Fabbri
- Department of Chemistry, University of Torino, Via P. Giuria 5, 10125, Torino, Italy
| | - F Dal Bello
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via P. Giuria 5, 10125, Torino, Italy
| | - C Medana
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via P. Giuria 5, 10125, Torino, Italy
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50
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Calza P, Vione D, Fabbri D, Aigotti R, Medana C. Imidazolium-Based Ionic Liquids in Water: Assessment of Photocatalytic and Photochemical Transformation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:10951-10958. [PMID: 26302036 DOI: 10.1021/acs.est.5b02738] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The photoinduced transformation of two ionic liquids, 1-methylimidazolium hydrogensulfate (HMIM) and 1-ethyl-3-methylimidazolium hydrogensulfate (EMIM), was investigated under photocatalytic conditions in the presence of irradiated TiO2. We monitored substrate disappearance, transformation products (TPs), degree of mineralization, and toxicity of the irradiated systems. Acute toxicity measures suggested in both cases the occurrence of more toxic TPs than the parent molecules. A total of five TPs were detected by HPLC-HRMS from HMIM and nine from EMIM. Complete mineralization and stoichiometric release of nitrogen was achieved for both compounds within 4 h of irradiation. The photochemical transformation kinetics and pathways in surface waters (direct photolysis and indirect photoreactions) were studied for EMIM, to assess its persistence in sunlit water bodies such as rivers or lakes. Environmental phototransformation would be dominated by direct photolysis, with half-life times of up to one month under fine-weather conditions.
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Affiliation(s)
- Paola Calza
- Department of Chemistry and ‡Department of Molecular Biotechnology and Health Sciences, University of Torino , via P. Giuria 5, 10125 Torino, Italy
| | - Davide Vione
- Department of Chemistry and ‡Department of Molecular Biotechnology and Health Sciences, University of Torino , via P. Giuria 5, 10125 Torino, Italy
| | - Debora Fabbri
- Department of Chemistry and ‡Department of Molecular Biotechnology and Health Sciences, University of Torino , via P. Giuria 5, 10125 Torino, Italy
| | - Riccardo Aigotti
- Department of Chemistry and ‡Department of Molecular Biotechnology and Health Sciences, University of Torino , via P. Giuria 5, 10125 Torino, Italy
| | - Claudio Medana
- Department of Chemistry and ‡Department of Molecular Biotechnology and Health Sciences, University of Torino , via P. Giuria 5, 10125 Torino, Italy
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