Photothermal Synergistic Effect of Pt₁/CuO-CeO₂ Single-Atom Catalysts Significantly Improving Toluene Removal

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(12), P. 8722 - 8732

Published: May 17, 2022

Photothermal synergistic catalytic oxidation of toluene over single-atom Pt catalysts was investigated. Compared with the conventional thermocatalytic in dark, conversion and CO2 yield 0.39Pt1/CuO-CeO2 under simulated solar irradiation (λ = 320-2500 nm, optical power density 200 mW cm-2) at 180 °C could be increased about 48%. An amount CuO added to CeO2 disperse a maximal loading 0.83 wt %. The effect between photo- thermocatalysis is very important for development new pollutant treatment technology high efficiency low energy consumption. Both light heat played an role present photothermal oxidation. showed good redox performance excellent properties utilized full-spectrum energy. Light illumination induced generation reactive oxygen species (•OH •O2-), which accelerated transformation intermediates, promoted release active sites on catalyst surface, improved reaction.

Language: Английский

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Gas-to-Aerosol Phase Partitioning of Atmospheric Water-Soluble Organic Compounds at a Rural Site in China: An Enhancing Effect of NH₃ on SOA Formation

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(7), P. 3915 - 3924

Published: March 17, 2022

Partitioning gaseous water-soluble organic compounds (WSOC) to the aerosol phase is a major formation pathway of atmospheric secondary aerosols (SOA). However, fundamental mechanism WSOC-partitioning process remains elusive. By simultaneous measurements both gas-phase WSOC (WSOCg) and aerosol-phase (WSOCp) formic acetic acids at rural site in Yangtze River Delta (YRD) region China during winter 2019, we showed that WSOCg campaign dominantly partitioned dry period (relative humidity (RH) < 80%) but liquid water (ALW) humid (RH > 80%), suggesting two distinct SOA processes region. In period, temperature was driving factor for uptake WSOCg. contrast, factors controlling absorption were ALW content pH, which significantly elevated by NH3 through NH4NO3 neutralization with acids. Additionally, found relative abundances WSOCp strong linear correlation throughout spatial distribution consistent NH3, further indicating key role national scale. Since constitutes part SOA, such promoting effect on production elevating partitioning suggests emission control necessary mitigating haze pollution, especially China.

Language: Английский

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Nitrogen-Containing Compounds Enhance Light Absorption of Aromatic-Derived Brown Carbon

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(7), P. 4005 - 4016

Published: Feb. 22, 2022

The formation of secondary brown carbon (BrC) is chemically complex, leading to an unclear relationship between its molecular composition and optical properties. Here, we present in-depth investigation molecular-specific properties aging BrC produced from the photooxidation ethylbenzene at varied NOx levels for first time. Due pronounced unsaturated products, mass absorption coefficient (MAC) organic aerosols (ESOA) 365 nm was higher than that biogenic SOA by a factor 10. A high level ([ethylbenzene]0/[NOx]0 < 10 ppbC ppb–1) found significantly increase average MAC300–700nm ESOA 0.29 m2 g–1. data two complementary high-resolution spectrometers quantum chemical calculations suggested nitrogen-containing compounds were largely responsible enhanced light high-NOx ESOA, multifunctional nitroaromatic (such as C8H9NO3 C8H9NO4) identified important chromophores. High-NOx underwent photobleaching upon direct exposure ultraviolet light. Photolysis did not lead significant decomposition C8H9NO4, indicating may serve relatively stable nitrogen reservoirs would effectively absorb solar radiation during daytime.

Language: Английский

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Precursors and Pathways Leading to Enhanced Secondary Organic Aerosol Formation during Severe Haze Episodes

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 55(23), P. 15680 - 15693

Published: Nov. 13, 2021

Molecular analyses help to investigate the key precursors and chemical processes of secondary organic aerosol (SOA) formation. We obtained sources molecular compositions in PM2.5 winter Beijing by online offline mass spectrometer measurements. Photochemical aqueous processing were both involved producing SOA during haze events. Aromatics, isoprene, long-chain alkanes or alkenes, carbonyls such as glyoxal methylglyoxal all important precursors. The enhanced formation severe event was predominantly contributed that promoted elevated amounts water for which multifunctional nitrates most followed compounds having four oxygen atoms their formulae. latter included dicarboxylic acids various oxidation products from isoprene aromatics well oligomers uptake. Nitrated phenols, organosulfates, methanesulfonic acid also but contributions minor. Our results highlight importance reducing nitrogen oxides nitrate future control. Additionally, highly oxygenated molecules with a low degree unsaturation polluted urban environments requires further research.

Language: Английский

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A review of secondary organic aerosols formation focusing on organosulfates and organic nitrates

Journal of Hazardous Materials, Journal Year: 2022, Volume and Issue: 430, P. 128406 - 128406

Published: Feb. 2, 2022

Language: Английский

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Amorphous SnO2 decorated ZnSn(OH)6 promotes interfacial hydroxyl polarization for deep photocatalytic toluene mineralization

Journal of Hazardous Materials, Journal Year: 2022, Volume and Issue: 444, P. 130436 - 130436

Published: Nov. 18, 2022

Language: Английский

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Mist cannon trucks can exacerbate the formation of water-soluble organic aerosol and PM_2.5 pollution in the road environment

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(12), P. 6775 - 6788

Published: June 20, 2023

Abstract. Mist cannon trucks have been widely applied in megacities China to reduce the road dust, since they are considered be more water saving and efficient than traditional sprinkling trucks. However, their effect on formation of water-soluble organic compounds pollution control fine particles (PM2.5) remains unknown. We characterized variations chemical compositions PM2.5 collected sides during simulated operations mist truck via Fourier transform ion cyclotron resonance mass spectrometry chromatography. The concentrations carbon showed a significant increase (62 %–70 %) after air spraying. Furthermore, we found that compounds, particularly nitrates, increased significantly interactions reactive gas-phase organics, atmospheric oxidants aerosol liquid spraying, although spraying had better suppressing dust ground aspersion. Moreover, segment where passed by was promoted, with an up 13 % concentration 25–35 min, average. Thus, application potentially worsens environment through levels production large number PM2.5. overall results provide not only valuable insights processes associated but also management strategies regulate operation China.

Language: Английский

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Wintertime fine aerosol particles composition and its evolution in two megacities of southern and northern China

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 914, P. 169778 - 169778

Published: Jan. 3, 2024

Language: Английский

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Effects of Relative Humidity and Photoaging on the Formation, Composition, and Aging of Ethylbenzene SOA: Insights from Chamber Experiments on Chlorine Radical-Initiated Oxidation of Ethylbenzene

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(4), P. 675 - 688

Published: April 1, 2024

The oxidation of alkyl-substituted aromatic molecules produces oxygenated volatile organic compounds (OVOCs) and secondary aerosols (SOA) that are major components ambient urban air. Despite their ubiquity, the impacts variable conditions, such as relative humidity (RH) actinic exposure, on physicochemical processes contribute to SOA formation still subject ongoing research refinement. In this work, we perform laboratory environmental chamber experiments use an I– FIGAERO–CIMS examine molecular composition high-NOx ethylbenzene products in response varied (dry 40% RH, 60% RH) during either dark aging or photoaging (with ∼354 nm UV-A lights). Experiments performed a mixed Cl OH radical environment. Compared chemistry, chemistry forms greater amount nitroaromatic by enhancing benzaldehyde phenolic H abstraction while also forming several organochlorine may serve tracers for which C2H3ClO2 (presumably chloroacetic acid) appears be most consistent stable. Organonitrate (ON) undergo hydrolytic photolytic losses. Nitroaromatic condense more efficiently under humid presumably due relatively high solubility hydroxy dihydroxy molecules, but do not appear stable condensed phase photoaging. Small oxygenates make up substantial portion increases at RH (due increased uptake) photolysis fragmentation). Photoaging initially leads degree oligomerization before continued eventual loss these other compounds. Our results show substantially impact evolution many gas- particle-phase species produced suggest factors can exert strong control over evolution, particularly regions.

Language: Английский

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Time-Resolved Molecular Characterization of Secondary Organic Aerosol Formed from OH and NO₃Radical Initiated Oxidation of a Mixture of Aromatic Precursors

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(31), P. 11572 - 11582

Published: July 27, 2023

Aromatic hydrocarbons (ArHCs) and oxygenated aromatic (ArHC–OHs) are emitted from a variety of anthropogenic activities important precursors secondary organic aerosol (SOA) in urban areas. Here, we analyzed compared the composition SOA formed oxidation mixture VOCs by OH NO3 radicals. The VOC was composed toluene (C7H8), p-xylene + ethylbenzene (C8H10), 1,3,5-trimethylbenzene (C9H12), phenol (C6H6O), cresol (C7H8O), 2,6-dimethylphenol (C8H10O), 2,4,6-trimethylphenol (C9H12O) proportion where were chosen to approximate day-time traffic-related emissions Delhi, alcohols make up 20% mixture. These prominent other cities as well, including those influenced biomass combustion. In experiments, large contributions CxHyOzN dimers (C15–C18) observed, corresponding fast formation within 15–20 min after start chemistry. Additionally, different combinations initial VOCs, highlighting importance exploring SOAs mixed systems. contrast, experiments with radicals yielded gradual mass formation, CxHyOz monomers (C6–C9) being dominant constituents. evolution time tracked degradation observed concurrent monomer species. rates dimer decomposition ∼2–3 times higher previously determined for α-pinene O3 SOA, dependence particle-phase reactions on oxidants. produced did not dramatically change over same frame. No measurable effects humidity SOA.

Language: Английский

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