Kinetics of Different Substituted Phenolic Compounds’ Aqueous OH Oxidation in Atmosphere

Atmosphere, Journal Year: 2025, Volume and Issue: 16(5), P. 567 - 567

Published: May 9, 2025

Atmospheric aqueous-phase reactions have been recognized as an important source of secondary organic aerosols (SOAs). However, the unclear reaction kinetics and mechanics hinder in-depth understanding SOA sources formation processes. This study selected ten different substituted phenolic compounds (termed PhCs) emitted from biomass burning precursors, to investigate using OH oxidation under simulated sunlight. The factors influencing rates were examined, contribution reactive oxygen species (ROS) was evaluated through quenching kinetic analysis experiments. results showed that pseudo-first-order rate constants (kobs) for ranged 1.03 × 10−4 7.85 s−1 sunlight irradiation with initial H2O2 concentration 3 mM. Precursors electron-donating groups (-OH, -OCH3, -CH3, etc.) exhibited higher electrophilic radical reactivity due enhanced electron density benzene ring, leading than those electron-withdrawing (-NO2, -CHO, -COOH). At pH 2, second-order (kPhCs, OH) lower at 5. kobs did not show dependence on pH. presence O2 facilitated phenols’ photodecay. Inorganic salts transition metal ions varying effects rates. Specifically, NO3− Cu2+ promoted kPhCs, OH, Cl− significantly while SO42− inhibited reaction. determined be in range 109~1010 L mol−1 via bimolecular method, a modest relationship their potential found. Additionally, multiple substituents can suppress toward •OH based Hammett plots. Quenching experiments revealed played dominant role compound degradation (exceeding 65%). Electron paramagnetic resonance confirmed generation singlet (1O2) system, probe-based quantification further explored concentrations 1O2 system. Based concentrations, atmospheric lifetimes estimated, providing valuable insights expanding databases chemical transformation persistence substances atmosphere.

Language: Английский

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Heterogeneous Reactions of Phenol on Different Components of Mineral Dust Aerosol: Formation of Oxidized Organic and Nitro-Phenolic Compounds

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(4), P. 259 - 272

Published: Feb. 23, 2024

Phenol, a common semi-volatile compound associated with different emissions including from plants and biomass burning, as well anthropogenic its derivatives, are important components of secondary organic aerosols (SOAs). Gas aqueous phase reactions phenol, in the presence photochemical drivers, fairly understood. However, despite observations showing aromatic content within SOA size mass increases during dust episodes, heterogeneous phenol mineral dusts poorly In current study, surface at gas/solid interface SiO2, α-Fe2O3, TiO2 have been investigated. Whereas reversible adsorption occurs on SiO2 surfaces, for both α-Fe2O3 reacts to form wide range OH substituted products. For surfaces that nitrated by gas-phase nitric acid prior exposure unique compounds nitro-phenolic compounds. Moreover, additional chemistry was observed when adsorbed products were exposed SO2 result formation nitrite nitrate redox SO2. Overall, this study reveals extensive complexity prevalent leading surfaces.

Language: Английский

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Aqueous Photosensitization of Syringaldehyde: Reactivity, Effects of Environmental Factors, and Formation of Brown Carbon Products

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(6), P. 1193 - 1203

Published: May 18, 2024

Phenolic aldehydes as brown carbon (BrC) chromophores may contribute to the mass of aqueous secondary organic aerosol (aqSOA) due their potential atmospheric photosensitizers. However, there is still a lack knowledge about sensitizing ability and impact environmental factors. In this work, we studied photosensitized behavior phenolic aldehyde, syringaldehyde (SyrAld), in solutions. Under illumination, influences factors such precursor concentration, solution pH, codissolved inorganic constituents (NaCl Na2SO4), matter (vanillyl alcohol, VAL, methoxyphenol produced during biomass burning) were investigated. Our results show that increasing pH salt concentration causes strong red shift absorption peak SyrAld, chloride salts sulfate exert different effects on photochemical reactivity SyrAld. Interestingly, opposite SyrAld VAL oxidation observed at wavelengths light. UV-B irradiation, inhibited degradation by light shielding effect, while under UV-A photosensitization promoted degradation. The major photooxidation products identified hydroxylated induced reactive oxygen species (OH radicals) dimerized direct triplet excited state (3SyrAld*) using UPLC-Q-TOF-MS. This work suggests play significant roles determining fate waters.

Language: Английский

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Aqueous-Phase Photooxidation of Vanillin in the Presence of Nitrite: Characteristics, Products, and Mechanism

ACS ES&T Air, Journal Year: 2024, Volume and Issue: 1(8), P. 860 - 870

Published: June 17, 2024

The present study investigates the reaction characteristics and mechanisms involved in aqueous-phase photooxidation of vanillin (VL) presence nitrite (NO2–). research entails a comprehensive analysis decay kinetics VL, composition products, changes absorbance under different pH conditions VL/NO2– molar ratios. results indicate notably rapid rate VL acidic conditions, with ratio emerging as crucial factor process. Notably, photoreaction between NO2– leads to formation secondary organic aerosols (aqSOA) comprising hydroxylation nitration oligomers that exhibit strong absorption near-ultraviolet visible light regions. findings, through theoretical calculations, shed on pathways This investigation contributes valuable insights into atmospheric phenolic compounds initiated by NO2–. obtained are particularly significant for understanding evolution aqSOA brown carbon (BrC).

Language: Английский

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Effects of Copper on the Chemical Kinetics and Brown Carbon Formation in the Aqueous ∙OH oxidation of Phenolic Compounds

Environmental Science Processes & Impacts, Journal Year: 2024, Volume and Issue: 26(9), P. 1526 - 1542

Published: Jan. 1, 2024

Many phenolic compounds (PhCs) in biomass burning and fossil fuel combustion emissions can partition into atmospheric aqueous phases (

Language: Английский

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Aqueous photochemical aging of water-soluble smoke particles from crop straws burning

Atmospheric Environment, Journal Year: 2024, Volume and Issue: unknown, P. 120897 - 120897

Published: Oct. 1, 2024

Language: Английский

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Measurement Report: Bio-physicochemistry of tropical clouds at Maïdo (Réunion Island, Indian Ocean): overview of results from the BIO-MAÏDO campaign

Published: Aug. 1, 2023

Abstract. The BIO-MAÏDO (Bio-physicochemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols formation) campaign was conducted from the 13th March to 4th April 2019 Réunion Island implied several scientific teams state-of-the-art instrumentation. part project with main objective is improve our understanding cloud formation (SOA) biogenic volatile compounds (BVOC) precursors in a environment. Instruments were deployed five sites: receptor site, observatory (MO) 2165 m asl, four sites along slope mountain. obtained dataset includes measurements gas-phase mixing ratio (VOC), characterization physical, chemical, biological (bacterial diversity) properties chemical (identification viable bacteria through culture-based approaches) water. In addition, turbulent parameters boundary layer, radiative fluxes, emissions fluxes BVOC surrounding vegetation measured help interpretation observed concentrations different phases. Dynamical analyses show two preferred trajectories routes for air masses arriving MO during daytime both corresponding return branches trade winds associated up-slopes thermal breezes. These likely encountered processing transport slope. highest oxygenated VOC (OVOC) above site located endemic forest contribution OVOC total MO. Chemical composition particles shows higher concentration oxalic acid more oxidized aerosol than other This signature photochemical aging potentially influenced by processing. Despite an in-depth analysis water, around 80 % average dissolved undefined highlighting complexity matter.

Language: Английский

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Atmospheric humic-like substances (HULIS) in Chongqing, Southwest China: Abundance, light absorption properties, and potential sources

Atmospheric Research, Journal Year: 2023, Volume and Issue: 295, P. 107016 - 107016

Published: Sept. 13, 2023

Language: Английский

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Measurement report: Bio-physicochemistry of tropical clouds at Maïdo (Réunion, Indian Ocean): overview of results from the BIO-MAÏDO campaign

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(7), P. 4129 - 4155

Published: April 8, 2024

Abstract. The BIO-MAÏDO (Bio-physicochemistry of tropical clouds at Maïdo: processes and impacts on secondary organic aerosols formation) campaign was conducted from 13 March to 4 April 2019 the island Réunion. main objective project improve understanding cloud formation (SOA) biogenic volatile compound (BVOC) precursors in a environment. Instruments were deployed five sites: receptor site, Maïdo Observatory (MO) 2165 m a.s.l. four sites along slope mountain. Observations include measurements compounds (VOCs) characterization physical, chemical biological (bacterial diversity culture-based approaches) properties water. Turbulent parameters boundary layer, radiative fluxes emissions BVOCs surrounding vegetation measured help interpret observed concentrations different phases. Dynamical analyses showed two preferred trajectory routes for air masses arriving MO during daytime. Both trajectories correspond return branches trade winds associated with upslope thermal breezes, where likely encountered processing. highest mixing ratios oxygenated VOCs (OVOCs) above site located endemic forest contribution OVOCs total MO. Chemical compositions particles daytime higher oxalic acid, tracer processing photochemical aging, more oxidized aerosol than other sites. Approximately 20 % dissolved analyzed. Additional by ultra-high-resolution mass spectrometry will explore complexity missing matter.

Language: Английский

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Experimental Study on Composition and Optic of Secondary Organic Aerosol Generated by Aqueous Photoxidation of Toluene in Presence of Copper Ions

Polish Journal of Environmental Studies, Journal Year: 2024, Volume and Issue: unknown

Published: July 2, 2024

Toluene and other aromatics can dissolve in atmospheric aqueous phases undergo photooxidation reactions, forming secondary organic aerosol (SOA) after water evaporation.Copper ion is a typical heavy metal able to change the composition optics of SOA.The reaction solution for OH-initiated toluene presence copper ions atomized by TSI 9302, absorbed silica gel simulate formation SOA particles this study.The formed are on-line off-line, characterized mass spectrometry spectroscopy.Experimental results demonstrate that laser desorption/ionization spectra contain molecular peaks at m/z = 108, 124, 140 cresol, mehtyl dihydroxybenzene, methyl trihydroxybenzene.The absorption peak intensity phenolic compounds 277 nm UV-Vis collection increases, electrospray ionization negative show polymer as high 641.These indicate catalyze production more hydroxyphenyl ether polymers polymerization cresol.These products have capacity strong light absorption, leading significant increase averaged coefficient () 200-600 SOA, which gently rises with an increment ions.These provide basis studying components ions.

Language: Английский

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