1
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Mabato BG, Li YJ, Huang DD, Chan CK. Aqueous-Phase Photoreactions of Mixed Aromatic Carbonyl Photosensitizers Yield More Oxygenated, Oxidized, and less Light-Absorbing Secondary Organic Aerosol (SOA) than Single Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:7924-7936. [PMID: 38652049 PMCID: PMC11080053 DOI: 10.1021/acs.est.3c10199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/25/2024]
Abstract
Aromatic carbonyls have been mainly probed as photosensitizers for aqueous secondary organic aerosol (aqSOA) and light-absorbing organic aerosol (i.e., brown carbon or BrC) formation, but due to their organic nature, they can also undergo oxidation to form aqSOA and BrC. However, photochemical transformations of aromatic carbonyl photosensitizers, particularly in multicomponent systems, are understudied. This study explored aqSOA formation from the irradiation of aromatic carbonyl photosensitizers in mixed and single systems under cloud/fog conditions. Mixed systems consisting of phenolic carbonyls only (VL + ActSyr + SyrAld: vanillin [VL] + acetosyringone [ActSyr] + syringaldehyde [SyrAld]) and another composed of both nonphenolic and phenolic carbonyls (DMB + ActSyr + SyrAld: 3,4-dimethoxybenzaldehyde [DMB], a nonphenolic carbonyl, + ActSyr + SyrAld) were compared to single systems of VL (VL*) and DMB (DMB*), respectively. In mixed systems, the shorter lifetimes of VL and DMB indicate their diminished capacity to trigger the oxidation of other organic compounds (e.g., guaiacol [GUA], a noncarbonyl phenol). In contrast to the slow decay and minimal photoenhancement for DMB*, the rapid photodegradation and significant photoenhancement for VL* indicate efficient direct photosensitized oxidation (i.e., self-photosensitization). Relative to single systems, the increased oxidant availability promoted functionalization in VL + ActSyr + SyrAld and accelerated the conversion of early generation aqSOA in DMB + ActSyr + SyrAld. Moreover, the increased availability of oxidizable substrates countered by stronger oxidative capacity limited the contribution of mixed systems to aqSOA light absorption. This suggests a weaker radiative effect of BrC from mixed photosensitizer systems than BrC from single photosensitizer systems. Furthermore, more oxygenated and oxidized aqSOA was observed with increasing complexity of the reaction systems (e.g., VL* < VL + ActSyr + SyrAld < VL + ActSyr + SyrAld + GUA). This work offers new insights into aqSOA formation by emphasizing the dual role of organic photosensitizers as oxidant sources and oxidizable substrates.
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Affiliation(s)
- Beatrix
Rosette Go Mabato
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
| | - Yong Jie Li
- Department
of Civil and Environmental Engineering, and Centre for Regional Ocean,
Faculty of Science and Technology, University
of Macau, Macau 999078, China
| | - Dan Dan Huang
- Shanghai
Academy of Environmental Sciences, Shanghai 200233, China
| | - Chak K. Chan
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
- Division
of Physical Sciences and Engineering, King
Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah 23955-6900, Kingdom
of Saudi Arabia
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2
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Zhang J, Shrivastava M, Ma L, Jiang W, Anastasio C, Zhang Q, Zelenyuk A. Modeling Novel Aqueous Particle and Cloud Chemistry Processes of Biomass Burning Phenols and Their Potential to Form Secondary Organic Aerosols. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:3776-3786. [PMID: 38346331 DOI: 10.1021/acs.est.3c07762] [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: 02/28/2024]
Abstract
Phenols emitted from biomass burning contribute significantly to secondary organic aerosol (SOA) formation through the partitioning of semivolatile products formed from gas-phase chemistry and multiphase chemistry in aerosol liquid water and clouds. The aqueous-phase SOA (aqSOA) formed via hydroxyl radical (•OH), singlet molecular oxygen (1O2*), and triplet excited states of organic compounds (3C*), which oxidize dissolved phenols in the aqueous phase, might play a significant role in the evolution of organic aerosol (OA). However, a quantitative and predictive understanding of aqSOA has been challenging. Here, we develop a stand-alone box model to investigate the formation of SOA from gas-phase •OH chemistry and aqSOA formed by the dissolution of phenols followed by their aqueous-phase reactions with •OH, 1O2*, and 3C* in cloud droplets and aerosol liquid water. We investigate four phenolic compounds, i.e., phenol, guaiacol, syringol, and guaiacyl acetone (GA), which represent some of the key potential sources of aqSOA from biomass burning in clouds. For the same initial precursor organic gas that dissolves in aerosol/cloud liquid water and subsequently reacts with aqueous phase oxidants, we predict that the aqSOA formation potential (defined as aqSOA formed per unit dissolved organic gas concentration) of these phenols is higher than that of isoprene-epoxydiol (IEPOX), a well-known aqSOA precursor. Cloud droplets can dissolve a broader range of soluble phenols compared to aqueous aerosols, since the liquid water contents of aerosols are orders of magnitude smaller than cloud droplets. Our simulations suggest that highly soluble and reactive multifunctional phenols like GA would predominantly undergo cloud chemistry within cloud layers, while gas-phase chemistry is likely to be more important for less soluble phenols. But in the absence of clouds, the condensation of low-volatility products from gas-phase oxidation followed by their reversible partitioning to organic aerosols dominates SOA formation, while the SOA formed through aqueous aerosol chemistry increases with relative humidity (RH), approaching 40% of the sum of gas and aqueous aerosol chemistry at 95% RH for GA. Our model developments of biomass-burning phenols and their aqueous chemistry can be readily implemented in regional and global atmospheric chemistry models to investigate the aqueous aerosol and cloud chemistry of biomass-burning organic gases in the atmosphere.
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Affiliation(s)
- Jie Zhang
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Manish Shrivastava
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Lan Ma
- Department of Land, Air and Water Resources, University of California, Davis, California 95616-8627, United States
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
| | - Wenqing Jiang
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
- Department of Environmental Toxicology, University of California, Davis, California 95616-5270, United States
| | - Cort Anastasio
- Department of Land, Air and Water Resources, University of California, Davis, California 95616-8627, United States
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
| | - Qi Zhang
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
- Department of Environmental Toxicology, University of California, Davis, California 95616-5270, United States
| | - Alla Zelenyuk
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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3
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Brown EK, Rovelli G, Wilson KR. pH jump kinetics in colliding microdroplets: accelerated synthesis of azamonardine from dopamine and resorcinol. Chem Sci 2023; 14:6430-6442. [PMID: 37325131 PMCID: PMC10266468 DOI: 10.1039/d3sc01576a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/21/2023] [Indexed: 06/17/2023] Open
Abstract
Recent studies report the dramatic acceleration of chemical reactions in micron-sized compartments. In the majority of these studies the exact acceleration mechanism is unknown but the droplet interface is thought to play a significant role. Dopamine reacts with resorcinol to form a fluorescent product azamonardine and is used as a model system to examine how droplet interfaces accelerate reaction kinetics. The reaction is initiated by colliding two droplets levitated in a branched quadrupole trap, which allows the reaction to be observed in individual droplets where the size, concentration, and charge are carefully controlled. The collision of two droplets produces a pH jump and the reaction kinetics are quantified optically and in situ by measuring the formation of azamonardine. The reaction was observed to occur 1.5 to 7.4 times faster in 9-35 micron droplets compared to the same reaction conducted in a macroscale container. A kinetic model of the experimental results suggests that the acceleration mechanism arises from both the more rapid diffusion of oxygen into the droplet, as well as increased reagent concentrations at the air-water interface.
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Affiliation(s)
- Emily K Brown
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
- Department of Chemistry, University of California Berkeley CA 94720 USA
| | - Grazia Rovelli
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA +1 510-495-2474
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4
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Ma L, Worland R, Tran T, Anastasio C. Evaluation of Probes to Measure Oxidizing Organic Triplet Excited States in Aerosol Liquid Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6052-6062. [PMID: 37011016 DOI: 10.1021/acs.est.2c09672] [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: 06/19/2023]
Abstract
Oxidizing triplet excited states of organic matter (3C*) drive numerous reactions in fog/cloud drops and aerosol liquid water (ALW). Quantifying oxidizing triplet concentrations in ALW is difficult because 3C* probe loss can be inhibited by the high levels of dissolved organic matter (DOM) and copper in particle water, leading to an underestimate of triplet concentrations. In addition, illuminated ALW contains high concentrations of singlet molecular oxygen (1O2*), which can interfere with 3C* probes. Our overarching goal is to find a triplet probe that has low inhibition by DOM and Cu(II) and low sensitivity to 1O2*. To this end, we tested 12 potential probes from a variety of compound classes. Some probes are strongly inhibited by DOM, while others react rapidly with 1O2*. One of the probe candidates, (phenylthiol)acetic acid (PTA), seems well suited for ALW conditions, with mild inhibition and fast rate constants with triplets, but it also has weaknesses, including a pH-dependent reactivity. We evaluated the performance of both PTA and syringol (SYR) as triplet probes in aqueous extracts of particulate matter. While PTA is less sensitive to inhibition than SYR, it results in lower triplet concentrations, possibly because it is less reactive with weakly oxidizing triplets.
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Affiliation(s)
- Lan Ma
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Reed Worland
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Theo Tran
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Cort Anastasio
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
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5
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Li F, Zhou S, Du L, Zhao J, Hang J, Wang X. Aqueous-phase chemistry of atmospheric phenolic compounds: A critical review of laboratory studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158895. [PMID: 36130630 DOI: 10.1016/j.scitotenv.2022.158895] [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: 07/18/2022] [Revised: 09/12/2022] [Accepted: 09/16/2022] [Indexed: 06/15/2023]
Abstract
Phenolic compounds (PhCs) are crucial atmospheric pollutants typically emitted by biomass burning and receive particular concerns considering their toxicity, light-absorbing properties, and involvement in secondary organic aerosol (SOA) formation. A comprehensive understanding of the transformation mechanisms on chemical reactions in atmospheric waters (i.e., cloud/fog droplets and aerosol liquid water) is essential to predict more precisely the atmospheric fate and environmental impacts of PhCs. Laboratory studies play a core role in providing the fundamental knowledge of aqueous-phase chemical transformations in the atmosphere. This article critically reviews recent laboratory advances in SOA formation from the aqueous-phase reactions of PhCs. It focuses primarily on the aqueous oxidation of PhCs driven by two atmospheric reactive species: OH radicals and triplet excited state organics, including the important chemical kinetics and mechanisms. The effects of inorganic components (i.e., nitrate and nitrite) and transition metal ions (i.e., soluble iron) are highlighted on the aqueous-phase transformation of PhCs and on the properties and formation mechanisms of SOA. The review is concluded with the current knowledge gaps and future perspectives for a better understanding of the atmospheric transformation and SOA formation potential of PhCs.
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Affiliation(s)
- Fenghua Li
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
| | - Shengzhen Zhou
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China.
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jun Zhao
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Jian Hang
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Xuemei Wang
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Institute for Environmental and Climate Research, Jinan University, Guangzhou 510000, China
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6
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Wang S, Zhao Y, Chan AWH, Yao M, Chen Z, Abbatt JPD. Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere. Chem Rev 2023; 123:1635-1679. [PMID: 36630720 DOI: 10.1021/acs.chemrev.2c00430] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Organic peroxides (POs) are organic molecules with one or more peroxide (-O-O-) functional groups. POs are commonly regarded as chemically labile termination products from gas-phase radical chemistry and therefore serve as temporary reservoirs for oxidative radicals (HOx and ROx) in the atmosphere. Owing to their ubiquity, active gas-particle partitioning behavior, and reactivity, POs are key reactive intermediates in atmospheric multiphase processes determining the life cycle (formation, growth, and aging), climate, and health impacts of aerosol. However, there remain substantial gaps in the origin, molecular diversity, and fate of POs due to their complex nature and dynamic behavior. Here, we summarize the current understanding on atmospheric POs, with a focus on their identification and quantification, state-of-the-art analytical developments, molecular-level formation mechanisms, multiphase chemical transformation pathways, as well as environmental and health impacts. We find that interactions with SO2 and transition metal ions are generally the fast PO transformation pathways in atmospheric liquid water, with lifetimes estimated to be minutes to hours, while hydrolysis is particularly important for α-substituted hydroperoxides. Meanwhile, photolysis and thermolysis are likely minor sinks for POs. These multiphase PO transformation pathways are distinctly different from their gas-phase fates, such as photolysis and reaction with OH radicals, which highlights the need to understand the multiphase partitioning of POs. By summarizing the current advances and remaining challenges for the investigation of POs, we propose future research priorities regarding their origin, fate, and impacts in the atmosphere.
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Affiliation(s)
- Shunyao Wang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai200240, China
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai200444, China
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, OntarioM5S 3E5, Canada
| | - Yue Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai200240, China
| | - Arthur W H Chan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, OntarioM5S 3E5, Canada
- School of the Environment, University of Toronto, Toronto, OntarioM5S 3E8, Canada
| | - Min Yao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai200240, China
| | - Zhongming Chen
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing100871, China
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, OntarioM5S 3H6, Canada
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7
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Xiao Y, Hu M, Li X, Zong T, Xu N, Hu S, Zeng L, Chen S, Song Y, Guo S, Wu Z. Aqueous secondary organic aerosol formation attributed to phenols from biomass burning. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157582. [PMID: 35882337 DOI: 10.1016/j.scitotenv.2022.157582] [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: 06/12/2022] [Revised: 07/17/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Biomass burning emits large quantities of phenols, which readily partition into the atmospheric aqueous phase and subsequently may react to produce aqueous secondary organic aerosol (aqSOA). For the first time, we quantitatively explored the influence of phenols emitted from biomass burning on aqSOA formation in the winter of Beijing. A typical haze episode associated with significant aqSOA formation was captured. During this episode, aqueous-phase processing of biomass burning promoted aqSOA formation was identified. Furthermore, high-resolution mass spectrum analysis provided molecular-level evidence of the phenolic aqSOA tracers. Estimation of aqSOA formation rate (RaqSOA) with compiled laboratory kinetic data indicated that biomass-burning phenols can efficiently produce aqSOA at midday, with RaqSOA of 0.42 μg m-3 h-1 accounting for 15 % of total aqSOA formation rate. The results highlight that aqSOA formation of phenols contributes the haze pollution. This implies the importance of regional joint control of biomass burning to mitigate the heavy haze.
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Affiliation(s)
- Yao Xiao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Xiao Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Taomou Zong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Nan Xu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shuya Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yu Song
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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8
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Aregahegn KZ, Felber T, Tilgner A, Hoffmann EH, Schaefer T, Herrmann H. Kinetics and Mechanisms of Aqueous-Phase Reactions of Triplet-State Imidazole-2-carboxaldehyde and 3,4-Dimethoxybenzaldehyde with α,β-Unsaturated Carbonyl Compounds. J Phys Chem A 2022; 126:8727-8740. [DOI: 10.1021/acs.jpca.2c05015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Kifle Z. Aregahegn
- Department of Chemistry, Debre Berhan University, P.O. Box 445, 1000 Debre Berhan, Ethiopia
| | - Tamara Felber
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, 04318 Leipzig, Germany
| | - Andreas Tilgner
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, 04318 Leipzig, Germany
| | - Erik H. Hoffmann
- 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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9
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Tong Y, Li M, Huang H, Long S, Sun W, Du J, Fan J, Wang L, Liu B, Peng X. Urea-Bond Scission Induced by Therapeutic Ultrasound for Biofunctional Molecule Release. J Am Chem Soc 2022; 144:16799-16807. [PMID: 36070479 DOI: 10.1021/jacs.2c03669] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrasound-triggered remote control of biomolecular functions in cells provides unique advantages for us to interrogate nature. However, strategies to design therapeutic ultrasound-responsive functional molecules remain elusive, and rare ultrasound-cleavable chemical bonds have been developed to date. Herein, therapeutic ultrasound (1 MHz)-induced scission of urea bonds for drug release is demonstrated for the first time. Such a transformation has been verified to be initiated by hydroxyl radicals generated in the interior of cavitation bubbles, occurring specifically at the cavitation bubble-liquid interface. A series of urea-bond-containing prodrugs based on methylene blue (MB), namely MBUs, are designed. Upon sonication with low-intensity therapeutic ultrasound, the urea bonds linked with primary amines can be selectively cleaved, and free MB is released in a physiologically relevant environment, accompanied by recovered absorbance, fluorescence, and photosensitivity. Moreover, an FDA-approved alkylating agent (i.e., melphalan) bearing urea bond is also developed (MBU-Mel), successfully achieving ultrasound-triggered drug release in deep-seated cancer cells (mimic with 1 cm pigskin), showing the scalability of our ultrasound-responsive molecule platform in bioactive molecules release. This may set the starting point for therapeutic ultrasound-induced drug release, making a forward step in "sonopharmacology".
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Affiliation(s)
- Yunkang Tong
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Mingle Li
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Haiqiao Huang
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Saran Long
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Wen Sun
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Jianjun Du
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Jiangli Fan
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
| | - Lei Wang
- State Key Laboratory of Fine Chemicals, Shenzhen University, Shenzhen 518071, China
| | | | - Xiaojun Peng
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China
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10
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Arciva S, Niedek C, Mavis C, Yoon M, Sanchez ME, Zhang Q, Anastasio C. Aqueous ·OH Oxidation of Highly Substituted Phenols as a Source of Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9959-9967. [PMID: 35775934 DOI: 10.1021/acs.est.2c02225] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Biomass burning (BB) releases large quantities of phenols (ArOH), which can partition into cloud/fog drops and aerosol liquid water (ALW), react, and form aqueous secondary organic aerosol (aqSOA). While simple phenols are too volatile to significantly partition into particle water, highly substituted ArOH partition more strongly and might be important sources of aqSOA in ALW. To investigate this, we measured the ·OH oxidation kinetics and aqSOA yields for six highly substituted ArOH from BB. Second-order rate constants are high, in the range (1.9-14) × 109 M-1 s-1 at pH 2 and (14-25) × 109 M-1 s-1 at pH 5 and 6. Mass yields of aqSOA are also high, with an average (±1σ) value of 82 (±12)%. ALW solutes have a range of impacts on phenol oxidation by ·OH: a BB sugar and some inorganic salts suppress oxidation, while a nitrate salt and transition metals enhance oxidation. Finally, we estimated rates of aqueous- and gas-phase formation of SOA from a single highly substituted phenol as a function of liquid water content (LWC), from conditions of cloud/fog (0.1 g-H2O m-3) to ALW (10 μg-H2O m-3). Formation of aqSOA is significant across the LWC range, although gas-phase ·OH becomes dominant under ALW conditions. We also see a generally large discrepancy between measured and modeled aqueous ·OH concentrations across the LWC range.
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Affiliation(s)
- Stephanie Arciva
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
| | - Christopher Niedek
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Camille Mavis
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
| | - Melanie Yoon
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
| | - Martin Esparza Sanchez
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
| | - Qi Zhang
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Cort Anastasio
- Department of Land, Air, and Water Resource, University of California, Davis, California 95616, United States
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11
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Liu C, Chen D, Chen X. Atmospheric Reactivity of Methoxyphenols: A Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2897-2916. [PMID: 35188384 DOI: 10.1021/acs.est.1c06535] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Methoxyphenols emitted from lignin pyrolysis are widely used as potential tracers for biomass burning, especially for wood burning. In the past ten years, their atmospheric reactivity has attracted increasing attention from the academic community. Thus, this work provides an extensive review of the atmospheric reactivity of methoxyphenols, including their gas-phase, particle-phase, and aqueous-phase reactions, as well as secondary organic aerosol (SOA) formation. Emphasis was placed on kinetics, mechanisms, and SOA formation. The reactions of methoxyphenols with OH and NO3 radicals were the predominant degradation pathways, which also had significant SOA formation potentials. The reaction mechanism of methoxyphenols with O3 is the cycloaddition of O3 to the benzene ring or unsaturated C═C bond, while H-abstraction and radical adduct formation are the main degradation channels of methoxyphenols by OH and NO3 radicals. Based on the published studies, knowledge gaps were pointed out. Future studies including experimental simulations and theoretical calculations of other representative kinds of methoxyphenols should be systematically carried out under complex pollution conditions. In addition, the ecotoxicity of their degradation products and their contribution to SOA formation from the atmospheric aging of biomass-burning plumes should be seriously assessed.
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Affiliation(s)
- Changgeng Liu
- School of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, P.R. China
| | - Dandan Chen
- School of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, P.R. China
| | - Xiao'e Chen
- School of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, P.R. China
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12
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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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13
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Ma L, Guzman C, Niedek C, Tran T, Zhang Q, Anastasio C. Kinetics and Mass Yields of Aqueous Secondary Organic Aerosol from Highly Substituted Phenols Reacting with a Triplet Excited State. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5772-5781. [PMID: 33851829 DOI: 10.1021/acs.est.1c00575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biomass burning emits large amounts of phenols, which can partition into cloud/fog drops and aerosol liquid water (ALW) and react to form aqueous secondary organic aerosol (aqSOA). Triplet excited states of organic compounds (3C*) are likely oxidants, but there are no rate constants with highly substituted phenols that have high Henry's law constants (KH) and are likely important in ALW. To address this gap, we investigated the kinetics of six highly substituted phenols with the triplet excited state of 3,4-dimethoxybenzaldehyde. Second-order rate constants at pH 2 are all fast, (2.6-4.6) × 109 M-1 s-1, while values at pH 5 are 2-5 times smaller. Rate constants are reasonably described by a quantitative structure-activity relationship with phenol oxidation potentials, allowing rate constants of other phenols to be predicted. Triplet-phenol kinetics are unaffected by ammonium sulfate, sodium chloride, galactose (a biomass-burning sugar), or Fe(III). In contrast, ammonium nitrate increases the rate of phenol loss by making hydroxyl radicals, while Cu(II) inhibits phenol decay. Mass yields of aqueous SOA from triplet reactions are large and range from 59 to 99%. Calculations using our data along with previous oxidant measurements indicate that phenols with high KH can be an important source of aqSOA in ALW, with 3C* typically the dominant oxidant.
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Affiliation(s)
- Lan Ma
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Chrystal Guzman
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Christopher Niedek
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Theodore Tran
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Qi Zhang
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Cort Anastasio
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
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14
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Rahbar A, Zahedi E, Aghaie H, Giahi M, Zare K. DFT Insight into the Kinetics and Mechanism of the OH
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‐Initiated Atmospheric Oxidation of Catechol: OH
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Addition and Hydrogen Abstraction Pathways. ChemistrySelect 2021. [DOI: 10.1002/slct.202100524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ali Rahbar
- Department of Chemistry, Science and Research Branch Islamic Azad University Tehran Iran
| | - Ehsan Zahedi
- Department of Chemistry, Herbal Medicines Raw Materials Research Center, Shahrood Branch Islamic Azad University, Shahrood Iran
| | - Hossein Aghaie
- Department of Chemistry, Science and Research Branch Islamic Azad University Tehran Iran
| | - Masoud Giahi
- Department of Chemistry, South-Tehran Branch Islamic Azad University Tehran Iran
| | - Karim Zare
- Department of Chemistry, Science and Research Branch Islamic Azad University Tehran Iran
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15
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Characterization of Products from the Aqueous-Phase Photochemical Oxidation of Benzene-Diols. ATMOSPHERE 2021. [DOI: 10.3390/atmos12050534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chemical processing in atmospheric aqueous phases, including cloud and fog drops, might be significant in reconciling the gap between observed and modeled secondary organic aerosol (SOA) properties. In this work, we conducted a relatively comprehensive investigation of the reaction products generated from the aqueous-phase photochemical oxidation of three benzene-diols (resorcinol, hydroquinone, and methoxyhydroquinone) by hydroxyl radical (·OH), triplet excited state (3C*) 3,4-dimethoxybenzaldehyde (3,4-DMB), and direct photolysis without any added oxidants. The results show that OH-initiated photo-degradation is the fastest of all the reaction systems. For the optical properties, the aqueous oxidation products generated under different reaction conditions all exhibited photo-enhancement upon illumination by simulated sunlight, and the light absorption was wavelength dependent on and increased as a function of the reaction time. The oxygen-to-carbon (O/C) ratio of the products also gradually increased against the irradiation time, indicating the persistent formation of highly oxygenated low-volatility products throughout the aging process. More importantly, aqueous-phase products from photochemical oxidation had an increased oxidative potential (OP) compared with its precursor, indicating they may more adversely impact health. The findings in this work highlight the importance of aqueous-phase photochemical oxidation, with implications for aqueous SOA formation and impacts on both the chemical properties and health effects of OA.
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16
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Jiang W, Misovich MV, Hettiyadura APS, Laskin A, McFall AS, Anastasio C, Zhang Q. Photosensitized Reactions of a Phenolic Carbonyl from Wood Combustion in the Aqueous Phase-Chemical Evolution and Light Absorption Properties of AqSOA. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5199-5211. [PMID: 33733745 DOI: 10.1021/acs.est.0c07581] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Guaiacyl acetone (GA) is a phenolic carbonyl emitted in significant quantities by wood combustion that undergoes rapid aqueous-phase oxidation to produce aqueous secondary organic aerosol (aqSOA). We investigate the photosensitized oxidation of GA by an organic triplet excited state (3C*) and the formation and aging of the resulting aqSOA in wood smoke-influenced fog/cloud water. The chemical transformations of the aqSOA were characterized in situ using a high-resolution time-of-flight aerosol mass spectrometer. Additionally, aqSOA samples collected over different time periods were analyzed using high-performance liquid chromatography coupled with a photodiode array detector and a high-resolution Orbitrap mass spectrometer (HPLC-PDA-HRMS) to provide details on the molecular composition and optical properties of brown carbon (BrC) chromophores. Our results show efficient formation of aqSOA from GA, with an average mass yield around 80%. The composition and BrC properties of the aqSOA changed significantly over the course of reaction. Three generations of aqSOA products were identified via positive matrix factorization analysis of the aerosol mass spectrometry data. Oligomerization and functionalization dominated the production of the first-generation aqSOA, whereas fragmentation and ring-opening reactions controlled the formation of more oxidized second- and third-generation products. Significant formation of BrC was observed in the early stages of the photoreaction, while organic acids were produced throughout the experiment. High-molecular weight molecules (m/z > 180) with high aromaticity were identified via HPLC-PDA-HRMS and were found to account for a majority of the UV-vis absorption of the aqSOA.
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Affiliation(s)
- Wenqing Jiang
- Department of Environmental Toxicology, University of California, Davis, California 95616-5270, United States
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
| | - Maria V Misovich
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
| | - Anusha P S Hettiyadura
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2050, United States
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907-2050, United States
| | - Alexander S McFall
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616-5270, United States
| | - Cort Anastasio
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616-5270, United States
| | - Qi Zhang
- Department of Environmental Toxicology, University of California, Davis, California 95616-5270, United States
- Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
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17
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Li F, Tsona NT, Li J, Du L. Aqueous-phase oxidation of syringic acid emitted from biomass burning: Formation of light-absorbing compounds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:144239. [PMID: 33412376 DOI: 10.1016/j.scitotenv.2020.144239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Syringic acid is a methoxyphenol model compound derived from biomass burning, and its photooxidation processes have important effects on atmospheric chemistry. However, its aqueous-phase photochemistry remains unclear. In this study, we systematically report the photooxidation of syringic acid induced by OH radicals in the aqueous phase. Employing the relative rate technique, the bimolecular rate constant for syringic acid reaction with OH radicals was acquired to be (1.1 ± 0.3) × 1010 M-1 s-1. Notably, colored products were formed as the reaction progressed. Furthermore, the UV-vis and fluorescence spectra confirmed the formation of light-absorbing organic species, and the results agreed well with previous results on atmospheric and natural humic-like substances (HULIS). The photooxidation products were detected by high performance liquid chromatography mass spectrometry (HPLC/MS), and a possible reaction mechanism was proposed. The aqueous-phase reaction of syringic acid would undergo functionalization process forming a hydroxylation product that enhances the degree of oxidation of aqueous secondary organic aerosol (aqSOA), and goes through dimerization process by C-C or C-O coupling of phenoxy radicals which may conduce to the formation of HULIS. These findings suggest that the photooxidation of syringic acid is an important pathway for highly oxygenated phenolic aqSOA formation, providing a secondary source for HULIS in a liquid phase or in deliquescent particles surrounded by a layer of water.
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Affiliation(s)
- Fenghua Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Narcisse T Tsona
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jianlong Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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18
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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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19
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An Z, Sun J, Han D, Mei Q, Wei B, Wang X, Xie J, Zhan J, He M. Effect of pH on ·OH-induced degradation progress of syringol/syringaldehyde and health effect. CHEMOSPHERE 2020; 255:126893. [PMID: 32402872 DOI: 10.1016/j.chemosphere.2020.126893] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
Syringol and syringaldehyde are widely present pollutants in atmosphere and wastewater due to lignin pyrolysis and draining of pulp mill effluents. The hydroxylation degradation mechanisms and kinetics and health effect assessment of them under high and low-NOx regimes in atmosphere and wastewater have been studied theoretically. The effect of pH on reaction mechanisms and rate constants in their ·OH-initiated degradation processes has been fully investigated. Results have suggested that aqueous solution played a positive role in the ·OH-initiated degradation reactions by decreasing the energy barriers of most reactions and changing the reactivity order of initial reactions. For Sy- and Sya- (anionic species of syringol and syringaldehyde), most initial reaction routes were more likely to occur than that of HSy and Hsya (neutral species of syringol and syringaldehyde). As the pH increased from 1 to 14, the overall rate constants (at 298 K) of syringol and syringaldehyde with ·OH in wastewater increased from 5.43 × 1010 to 9.87 × 1010 M-1 s-1 and from 3.70 × 1010 to 1.14 × 1011 M-1 s-1, respectively. In the NOx-rich environment, 4-nitrosyringol was the most favorable product, while ring-opening oxygenated chemicals were the most favorable products in the NOx-poor environment. On the whole, the NOx-poor environment could decrease the toxicities during the hydroxylation processes of syringol and syringaldehyde, which was the opposite in a NOx-rich environment. ·OH played an important role in the methoxyphenols degradation and its conversion into harmless compounds in the NOx-poor environment.
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Affiliation(s)
- Zexiu An
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China
| | - Jianfei Sun
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China
| | - Dandan Han
- School of Chemistry and Chemical Engineering, Heze University, Heze, 274015, PR China
| | - Qiong Mei
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China
| | - Bo Wei
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China
| | - Xueyu Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
| | - Ju Xie
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, PR China
| | - Jinhua Zhan
- Key Laboratory for Colloid & Interface Chemistry of Education Ministry, Department of Chemistry, Shandong University, Jinan, 250100, PR China
| | - Maoxia He
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China.
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20
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Hullar T, Bononi FC, Chen Z, Magadia D, Palmer O, Tran T, Rocca D, Andreussi O, Donadio D, Anastasio C. Photodecay of guaiacol is faster in ice, and even more rapid on ice, than in aqueous solution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1666-1677. [PMID: 32671365 DOI: 10.1039/d0em00242a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Snowpacks contain a wide variety of inorganic and organic compounds, including some that absorb sunlight and undergo direct photoreactions. How the rates of these reactions in, and on, ice compare to rates in water is unclear: some studies report similar rates, while others find faster rates in/on ice. Further complicating our understanding, there is conflicting evidence whether chemicals react more quickly at the air-ice interface compared to in liquid-like regions (LLRs) within the ice. To address these questions, we measured the photodegradation rate of guaiacol (2-methoxyphenol) in various sample types, including in solution, in ice, and at the air-ice interface of nature-identical snow. Compared to aqueous solution, we find modest rate constant enhancements (increases of 3- to 6-fold) in ice LLRs, and much larger enhancements (of 17- to 77-fold) at the air-ice interface of nature-identical snow. Our computational modeling suggests the absorption spectrum for guaiacol red-shifts and increases on ice surfaces, leading to more light absorption, but these changes explain only a small portion (roughly 2 to 9%) of the observed rate constant enhancements in/on ice. This indicates that increases in the quantum yield are primarily responsible for the increased photoreactivity of guaiacol on ice; relative to solution, our results suggest that the quantum yield is larger by a factor of roughly 3-6 in liquid-like regions and 12-40 at the air-ice interface.
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Affiliation(s)
- Ted Hullar
- Department of Land, Air and Water Resources, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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Chen Y, Li N, Li X, Tao Y, Luo S, Zhao Z, Ma S, Huang H, Chen Y, Ye Z, Ge X. Secondary organic aerosol formation from 3C ⁎-initiated oxidation of 4-ethylguaiacol in atmospheric aqueous-phase. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:137953. [PMID: 32213404 DOI: 10.1016/j.scitotenv.2020.137953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/13/2020] [Accepted: 03/13/2020] [Indexed: 06/10/2023]
Abstract
In this study, we investigated aqueous-phase triplet excited states (3C⁎)-induced photo-degradation of 4-ethylguaiacol (EG) under both simulated sunlight and ultraviolet (UV) light irradiations. Through quencher experiments, the relative contributions of reactive oxygen species (ROS, such as 1O2/O2-/·OH) and 3C⁎ were calculated and results showed three reactive species, e.g., 3C⁎, 1O2 and O2-, all seemed to play important roles in the photo-degradation of EG, but contribution from ·OH was relatively minor. High steady-state 1O2 concentration after 1 h irradiation further revealed the major contribution of 1O2 to photo-degradation under Xe light irradiation. The degradation experiment under three saturated gases (air, O2 and N2) showed that the degradation rate in air-saturated condition was the largest owing to synergistic effect of 1O2 and 3C⁎. Oxidative capacity of aqueous secondary organic aerosol (aqSOA) increased with reaction time by monitoring oxygen-to‑carbon (O/C) ratio and carbon oxidation state (OSc) via an aerodyne soot particle aerosol mass spectrometer (SP-AMS). Moreover, aqSOA mass yields were calculated via SP-AMS data. The UV-vis spectral change suggested formation of light-absorbing organics at first stage under simulated sunlight irradiation. Based on the identified products and the reactive intermediates, we postulated that 3C⁎-induced oxidation might be attributed to direct reactions by 3C⁎ and 1O2, chemical reaction by ROS, as well as oligomerization via H-abstraction. To the best of our knowledge, this is the first time to explore systematically reaction pathways of 4-ethylguaiacol under 3C∗ radical on the basis of thorough analysis of products and reactive species. Our findings highlight the impacts of aqSOA from biomass burning emissions on air quality and climate change.
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Affiliation(s)
- Yantong Chen
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Nanwang Li
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Xudong Li
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Ye Tao
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shipeng Luo
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Zhuzi Zhao
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shuaishuai Ma
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Hongying Huang
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Yanfang Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhaolian Ye
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China.
| | - Xinlei Ge
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
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22
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McFall AS, Johnson AW, Anastasio C. Air-Water Partitioning of Biomass-Burning Phenols and the Effects of Temperature and Salinity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3823-3830. [PMID: 32162913 DOI: 10.1021/acs.est.9b06443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Biomass burning (BB) emits organic gases that, with chemical aging, can form secondary organic aerosol (SOA) in both the gas and aqueous phases. One class of biomass-burning emissions, phenols, are of interest because they react rapidly in the aqueous phase to efficiently form SOA, which might affect climate and human health. However, while measurements exist for the air-water partitioning constants of some simple phenols, Henry's law constants (KH) are unknown for more complex BB phenols. In this work, we use a custom-built apparatus to measure KH for a suite of biomass-burning phenols that span a wide range of air-water partitioning coefficients. Comparing our measurements to predicted values from EPI Suite shows that this model consistently overestimates KH unless a suitable measured phenol KH value is included to adjust the calculations. In addition, we determine the effect of five salts on phenol partitioning by measuring the Setschenow coefficients (KS). Across the eight phenols we examined, values of KS depend primarily on salt identity and descend in the order (NH4)2SO4 > NaCl > NH4Cl ≥ KNO3 > NH4NO3. Lastly, we use our KH and KS results to discuss the aqueous processing of biomass-burning phenols in cloud/fog water versus aerosol liquid water.
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Affiliation(s)
- Alexander S McFall
- Department of Land, Air, and Water Resources, University of California, Davis, Davis, California 95670, United States
| | - Alex W Johnson
- Department of Land, Air, and Water Resources, University of California, Davis, Davis, California 95670, United States
| | - Cort Anastasio
- Department of Land, Air, and Water Resources, University of California, Davis, Davis, California 95670, United States
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Kroflič A, Schaefer T, Huš M, Phuoc Le H, Otto T, Herrmann H. OH radicals reactivity towards phenol-related pollutants in water: temperature dependence of the rate constants and novel insights into the [OH-phenol]˙ adduct formation. Phys Chem Chem Phys 2020; 22:1324-1332. [PMID: 31850419 DOI: 10.1039/c9cp05533a] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Substituted phenols are known to readily react with the hydroxyl radical (OH˙), which is the most powerful atmospheric oxidant and is also most often used in advanced oxidation processes (AOP) for wastewater treatment. We report temperature-dependent (278.15-318.15 K) second order kinetic rate constants for the aqueous-phase reactions of OH˙ with phenol and four substituted phenols: catechol, phloroglucinol, pyrogallol and 3-methylcatechol, with the last two measured for the first time. The constructed Hammett plots for mono- and di-substituted phenols have the potential to be further applied for predicting the reaction rate constants of other substituted phenols at 298.15 K. This will significantly facilitate the optimization of AOP and improve the predictive capabilities of atmospheric multiphase models in the future. Moreover, an advancement in the understanding of the underlying mechanism, i.e. OH˙ addition to the aromatic ring is made by theoretical calculations at the M06-2X level. We demonstrate that the position of substituents on the aromatic ring is important for the [OH-phenol]˙ adduct formation, which is supported by the experiment and theoretical calculations. Adjacent and nonadjacent electron donor/acceptor substituents differently impact the interplay between the activation energy and entropy. We also show that explicit solvation has to be accounted for in theoretical models in order to explicitly describe the formation of the transition state.
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Affiliation(s)
- Ana Kroflič
- Leibniz-Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany. and National Institute of Chemistry, Department of Analytical Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Thomas Schaefer
- Leibniz-Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany.
| | - Matej Huš
- National Institute of Chemistry, Department of Catalysis and Chemical Reaction Engineering, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Hoa Phuoc Le
- Leibniz-Institute for Tropospheric Research (TROPOS), Atmospheric Chemistry Department (ACD), Permoserstrasse 15, 04318 Leipzig, Germany.
| | - Tobias Otto
- 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. and School of Environmental Science and Engineering, Shandong University, Binhairoad 72, 266237 Qingdao, China
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Ye Z, Qu Z, Ma S, Luo S, Chen Y, Chen H, Chen Y, Zhao Z, Chen M, Ge X. A comprehensive investigation of aqueous-phase photochemical oxidation of 4-ethylphenol. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:976-985. [PMID: 31390715 DOI: 10.1016/j.scitotenv.2019.06.276] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/11/2019] [Accepted: 06/18/2019] [Indexed: 06/10/2023]
Abstract
Secondary organic aerosol (SOA) species formed in atmospheric aqueous phases is recently recognized as an important contributor to fine aerosols, which is known to be a prominent human health risk factor internationally. This work, for the first time, systematically investigated aqueous-phase photochemical oxidation of 4-ethylphenol (4-EP) - a model compound from biomass burning and a surrogate of intermediate volatility organic compounds, under both ultraviolet (UV) (Hg lamp) and simulated sunlight (Xe lamp). We found that 4-EP could degrade upon hydroxal radical (OH) oxidation under UV light nearly 15 times faster than that under simulated sunlight, but large aqueous SOA (aqSOA) yields (108%-122%) were observed under both situations. AqSOA masses and oxidation states continuously increased under simulated sunlight, yet they increased first then decreased quickly under UV light. We proposed a reaction scheme based on identified products, showing that oligomerization, functionalization and fragmentation all can occur during 4-EP oxidation. Our results demonstrate that OH radical may suppress oligomerization and functionalization, but is favorable for fragmentation. Under UV light with H2O2 (high OH), fragmentation was dominant, producing more volatile and smaller molecules, and less aqSOA in later oxidation; Under simulated sunlight with H2O2 (moderate OH), functionalization that can form hydroxylated monomer was more important. Moreover, 4-EP oxidation by the organic triplet excited state (3C*) could form species with stronger visible light absorptivity than those from OH-mediated oxidation, and the absorptivity showed positive link with contents of humic-like substances.
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Affiliation(s)
- Zhaolian Ye
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Zhenxiu Qu
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shuaishuai Ma
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Shipeng Luo
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Yantong Chen
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Hui Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yanfang Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhuzi Zhao
- College of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Mindong Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Xinlei Ge
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
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He L, Schaefer T, Otto T, Kroflič A, Herrmann H. Kinetic and Theoretical Study of the Atmospheric Aqueous-Phase Reactions of OH Radicals with Methoxyphenolic Compounds. J Phys Chem A 2019; 123:7828-7838. [PMID: 31397571 DOI: 10.1021/acs.jpca.9b05696] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Methoxyphenols, which are emitted through biomass burning, are an important species in atmospheric chemistry. In the present study, temperature-dependent aqueous-phase OH radical reactions of six methoxyphenols and two related phenols have been investigated through laser flash photolysis and the density functional theory. The rate constants obtained were in a range of (1.1-1.9) × 1010 L mol-1 s-1 with k(3-MC) > k(Cre) ≈ k(Syr) ≈ k(MEP) > k(Res) > k(3-MP) > k(2-EP) ≈ k(2-MP). We derived the parameters of these reactions from the obtained T-dependent rate constants and found a mean Arrhenius activation energy of 16.9 kJ mol-1. The diffusion rate constants were calculated for each case and compared to the measured ones. Generally, the rate constants are found to be close to fully diffusion-controlled (kdiff = (1.4-1.5) × 1010 L mol-1 s-1 for all reactions). A structure-function relationship was established through the measurement result, which could be used for predicting unknown rate constants of other phenolic compounds. All of these findings are expected to enhance the predictive capabilities of models, such as the chemical aqueous-phase radical mechanism.
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Affiliation(s)
- Lin He
- 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
| | - Tobias Otto
- Atmospheric Chemistry Department (ACD) , Leibniz-Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , 04318 Leipzig , Germany
| | - Ana Kroflič
- Atmospheric Chemistry Department (ACD) , Leibniz-Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , 04318 Leipzig , Germany.,Department of Analytical Chemistry , National Institute of Chemistry , Hajdrihova 19 , SI-1000 Ljubljana , Slovenia
| | - Hartmut Herrmann
- Atmospheric Chemistry Department (ACD) , Leibniz-Institute for Tropospheric Research (TROPOS) , Permoserstrasse 15 , 04318 Leipzig , Germany.,School of Environmental Science and Engineering , Shandong University , Binhai Road 72 , 266237 Qingdao , China
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Tomaz S, Cui T, Chen Y, Sexton KG, Roberts JM, Warneke C, Yokelson RJ, Surratt JD, Turpin BJ. Photochemical Cloud Processing of Primary Wildfire Emissions as a Potential Source of Secondary Organic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11027-11037. [PMID: 30153017 DOI: 10.1021/acs.est.8b03293] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We investigated the gas-phase chemical composition of biomass burning (BB) emissions and their role in aqueous secondary organic aerosol (aqSOA) formation through photochemical cloud processing. A high-resolution time-of-flight chemical ionization mass spectrometer using iodide reagent ion chemistry detected more than 100 gas-phase compounds from the emissions of 30 different controlled burns during the 2016 Fire Influence on Regional and Global Environments Experiment (FIREX) at the Fire Science Laboratory. Compounds likely to partition to cloudwater were selected based on high atomic oxygen-to-carbon ratio and abundance. Water solubility was confirmed by detection of these compounds in water after mist chamber collection during controlled burns and analysis using ion chromatography and electrospray ionization interfaced to high-resolution time-of-flight mass spectrometry. Known precursors of aqSOA were found in the primary gaseous BB emissions (e.g., phenols, acetate, and pyruvate). Aqueous OH oxidation of the complex biomass burning mixtures led to rapid depletion of many compounds (e.g., catechol, levoglucosan, methoxyphenol) and formation of others (e.g., oxalate, malonate, mesoxalate). After 150 min of oxidation (approximatively 1 day of cloud processing), oxalate accounted for 13-16% of total dissolved organic carbon. Formation of known SOA components suggests that cloud processing of primary BB emissions forms SOA.
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Affiliation(s)
- Sophie Tomaz
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Tianqu Cui
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Yuzhi Chen
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Kenneth G Sexton
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - James M Roberts
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
| | - Carsten Warneke
- Chemical Sciences Division , NOAA Earth System Research Laboratory , Boulder , Colorado 80305 , United States
- Cooperative Institute for Research in Environmental Sciences , University of Colorado , Boulder , Colorado 80309 , United States
| | - Robert J Yokelson
- Department of Chemistry and Biochemistry , University of Montana , Missoula , Montana 59812 , United States
| | - Jason D Surratt
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Barbara J Turpin
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health , The University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
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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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Arnold WA, Oueis Y, O'Connor M, Rinaman JE, Taggart MG, McCarthy RE, Foster KA, Latch DE. QSARs for phenols and phenolates: oxidation potential as a predictor of reaction rate constants with photochemically produced oxidants. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:324-338. [PMID: 27942650 DOI: 10.1039/c6em00580b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Quantitative structure-activity relationships (QSARs) for prediction of the reaction rate constants of phenols and phenolates with three photochemically produced oxidants, singlet oxygen, carbonate radical, and triplet excited state sensitizers/organic matter, are developed. The predictive variable is the one-electron oxidation potential (E1), which is calculated for each species using density functional theory. The reaction rate constants are obtained from the literature, and for singlet oxygen, are augmented with new experimental data. Calculated E1 values have a mean unsigned error compared to literature values of 0.04-0.06 V. For singlet oxygen, a single linear QSAR that includes both phenols and phenolates is developed that predicts experimental rate constants, on average, to within a factor of three. Predictions for only 6 out of 87 compounds are off by more than a factor of 10. A more limited data set for carbonate radical reactions with phenols and phenolates also gives a single linear QSAR with prediction of rate constant being accurate to within a factor of three. The data for the reactions of phenols with triplet state sensitizers demonstrate that two sensitizers, 2-acetonaphthone and methylene blue, most closely predict the reactivity trend of triplet excited state organic matter with phenols. Using sensitizers with stronger reduction potentials could lead to overestimation of rate constants and thus underestimation of phenolic pollutant persistence.
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Affiliation(s)
- William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Yan Oueis
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Meghan O'Connor
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
| | - Johanna E Rinaman
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Miranda G Taggart
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Rachel E McCarthy
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Kimberley A Foster
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
| | - Douglas E Latch
- Department of Chemistry, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA.
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Chen Z, Anastasio C. Concentrations of a triplet excited state are enhanced in illuminated ice. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:12-21. [PMID: 28060386 DOI: 10.1039/c6em00534a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Photochemical reactions influence the fates and lifetimes of organic compounds in snow and ice, both through direct photoreactions and via photoproduced transient species such as hydroxyl radical (˙OH) and, perhaps, triplet excited states of organic compounds (i.e., triplets). While triplets can be important oxidants in atmospheric drops and surface waters, little is known of this class of oxidants in frozen samples. To investigate this, we examined the photoreaction of phenol with the triplet state of 3,4-dimethoxybenzaldehyde (3DMB*), a product from biomass combustion, in illuminated laboratory ices. Our results show that the rate of phenol loss due to 3DMB* is, on average, increased by a factor of 95 ± 50 in ice compared to the equivalent liquid sample. We find that this experimentally measured freeze concentration factor, FEXP, is independent of total solute concentration and temperature, in contrast to what is expected from a liquid-like region whose composition follows freezing point depression. We also find that FEXP for triplets is independent of pH, although the rates of phenol loss increase with decreasing pH in both solution and ice. The enhancement in the rate of phenol loss in/on ice indicates that concentrations of triplet excited states are enhanced in ice relative to solution and suggests that this class of oxidants might be a significant sink for organics in snow and ice.
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Affiliation(s)
- Zeyuan Chen
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA. and Atmospheric Science Graduate Group, University of California, Davis, 1 Shields Ave., Davis, CA, USA
| | - Cort Anastasio
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA. and Atmospheric Science Graduate Group, University of California, Davis, 1 Shields Ave., Davis, CA, USA
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Finlayson-Pitts BJ. Introductory lecture: atmospheric chemistry in the Anthropocene. Faraday Discuss 2017; 200:11-58. [DOI: 10.1039/c7fd00161d] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The term “Anthropocene” was coined by Professor Paul Crutzen in 2000 to describe an unprecedented era in which anthropogenic activities are impacting planet Earth on a global scale. Greatly increased emissions into the atmosphere, reflecting the advent of the Industrial Revolution, have caused significant changes in both the lower and upper atmosphere. Atmospheric reactions of the anthropogenic emissions and of those with biogenic compounds have significant impacts on human health, visibility, climate and weather. Two activities that have had particularly large impacts on the troposphere are fossil fuel combustion and agriculture, both associated with a burgeoning population. Emissions are also changing due to alterations in land use. This paper describes some of the tropospheric chemistry associated with the Anthropocene, with emphasis on areas having large uncertainties. These include heterogeneous chemistry such as those of oxides of nitrogen and the neonicotinoid pesticides, reactions at liquid interfaces, organic oxidations and particle formation, the role of sulfur compounds in the Anthropocene and biogenic–anthropogenic interactions. A clear and quantitative understanding of the connections between emissions, reactions, deposition and atmospheric composition is central to developing appropriate cost-effective strategies for minimizing the impacts of anthropogenic activities. The evolving nature of emissions in the Anthropocene places atmospheric chemistry at the fulcrum of determining human health and welfare in the future.
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Heath AA, Valsaraj KT. Effects of Temperature, Oxygen Level, Ionic Strength, and pH on the Reaction of Benzene with Hydroxyl Radicals at the Air-Water Interface in Comparison to the Bulk Aqueous Phase. J Phys Chem A 2015; 119:8527-36. [PMID: 26158391 DOI: 10.1021/acs.jpca.5b05152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atmospheric aerosols (e.g., fog droplets) are complex, multiphase mediums. Depending on location, time of day, and/or air mass source, there can be considerable variability within these droplets, relating to temperature, pH, and ionic strength. Due to the droplets' inherently small size, the reactions that occur within these droplets are determined by bulk aqueous phase and air-water interfacial conditions. In this study, the reaction of benzene and hydroxyl radicals is examined kinetically in a thin-film flow-tube reactor. By varying the aqueous volume (e.g., film thickness) along the length of the reactor, both bulk and interfacial reaction rates are measured from a single system. Temperature, pH, and ionic strength are varied to model conditions typical of fog events. Oxygen-poor conditions are measured to study oxygen's overall effect on the reaction pathway. Initial rate activation energies and the bulk aqueous phase and interfacial contributions to the overall rate constant are also obtained.
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Affiliation(s)
- Aubrey A Heath
- Cain Department of Chemical Engineering, Louisiana State University, 212 Jesse Coates Hall, Baton Rouge, Louisiana 70803-7303, United States
| | - Kalliat T Valsaraj
- Cain Department of Chemical Engineering, Louisiana State University, 212 Jesse Coates Hall, Baton Rouge, Louisiana 70803-7303, United States
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