Geocatalytic Uptake of Ozone onto Natural Mineral Dust

Wang, Xianjie; Romanías, Manolis N.; Thévenet, F.; Rousseau, Antoine

doi:10.3390/catal8070263

Cited by 12 publications

(19 citation statements)

References 41 publications

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“…However, this may not be the case after eruptions, when the mixing ratios of halogen-containing gases have returned to background levels, but volcanic dust emissions persist. Ozone depletion has also been observed within Saharan and Gobi dust plumes; here, in contrast, ozone loss has been attributed to the direct uptake of ozone (as observed in the laboratory − ) and/or the scavenging of its precursors (i.e., nitrogen oxides) by mineral dust. Although the composition of lower-latitude dusts differs significantly from that of Icelandic dust, these observations nonetheless suggest that the interaction of ozone with high-latitude dust may also be important.…”

Section: Introductionmentioning

confidence: 88%

Ozone Chemistry and Photochemistry at the Surface of Icelandic Volcanic Dust: Insights from Elemental Speciation Analysis

Abou-Ghanem

Jensen

Styler

et al. 2021

ACS Earth Space Chem.

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Volcanic particulate matter (PM), whether emitted directly as ash or indirectly via suspension of glaciogenic sediments, comprises a large fraction of atmospheric PM in Iceland, a major high-latitude dust source area. This PM leads to direct reductions in air quality and health; in addition, because it provides a surface for reactions with trace pollutant gases, it also has the potential to indirectly influence the chemical composition of the troposphere. Here, we investigate the reaction of gas-phase ozone with a volcanic dust sample obtained from the Mýrdalssandur source region in southern Iceland. We find that the steady-state surface area-scaled ozone uptake coefficient (γBET) for this sample decreases with increasing ozone mixing ratio and relative humidity, which implies that the reaction proceeds via a Langmuir–Hinshelwood mechanism with water vapor as competitive adsorbate. Using the γBET values we obtain here, we conclude that the ozone flux to volcanic PM would be <10% of its flux to the ground surface under typical Icelandic weather conditions, even during major dust events. Interestingly, although the Mýrdalssandur dust sample is high in elemental Ti, which in its anatase and rutile forms is a powerful semiconductor photocatalyst, its photochemistry is relatively modest. We use electron microprobe analysis to help resolve this apparent contradiction: in particular, we show that the bulk of the Ti in this sample is present in its glass fraction, with the remainder present not as anatase or rutile but rather in other predicted mineral phases (pyroxene, plagioclase, ilmenite, titanomagnetite, and olivine). These results highlight the advantages of using elemental speciation analysis to understand the atmospheric reactivity of volcanic PM.

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Section: Introductionmentioning

confidence: 88%

Ozone Chemistry and Photochemistry at the Surface of Icelandic Volcanic Dust: Insights from Elemental Speciation Analysis

Abou-Ghanem

Jensen

Styler

et al. 2021

ACS Earth Space Chem.

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“…It has therefore been suggested that it exhibits higher surface reactivity toward gaseous species . Our recent work also reveals that Gobi dust shows higher surface reactivity toward ozone uptake than classical single metal oxides, which are recognized as ozone decomposers . Moreover, Gobi Desert is the second largest emission source of dust on earth, which makes Gobi dust one of the most representative mineral dust constituents in the atmosphere. − …”

Section: Introductionmentioning

confidence: 85%

“…It is chiefly emitted into the atmosphere from arid or semiarid areas on earth, with an annual emission of ca. 1600 Tg and global-scale transport. − Atmospheric chemistry studies have demonstrated that the mineral dust in the atmosphere, such as mixtures of clays, feldspars, quartz, calcium carbonate, and metal oxides, , provides surfaces for heterogeneous interactions with gaseous species molecules, thus influencing the environmental fate of atmospheric trace gases. − Among the diversity of natural dust, the dust from the Gobi Desert in Asia, Gobi dust, has a higher Al/Si ratio compared to the dust from other origins, such as dust from the Saharan regions. It has therefore been suggested that it exhibits higher surface reactivity toward gaseous species .…”

Section: Introductionmentioning

confidence: 99%

“…10 Our recent work also reveals that Gobi dust shows higher surface reactivity toward ozone uptake than classical single metal oxides, which are recognized as ozone decomposers. 9 Moreover, Gobi Desert is the second largest emission source of dust on earth, which makes Gobi dust one of the most representative mineral dust constituents in the atmosphere. 12−14 Organic acids are key chemical trace constituents in the atmosphere, and they account for approximately 25% of the non-methane hydrocarbon species.…”

Section: ■ Introductionmentioning

confidence: 99%

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Uptake Mechanism of Acetic Acid onto Natural Gobi Dust

Wang

Romanías

Pei

et al. 2020

ACS Earth Space Chem.

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A challenge for understanding the environmental fate of atmospheric organic acids is to evaluate the impacts of their heterogeneous interactions with mineral dust aerosols in the atmosphere. However, the uptake of organic acids on authentic natural mineral dust is rarely investigated under atmosphere-relevant conditions. Herein, we investigated the uptake of acetic acid (AcA) onto a natural mineral dust from the Gobi Desert, Gobi dust, under atmosphere-relevant conditions, combining both the gas-phase and adsorbed-phase approaches. Gobi dust is evidenced to reversibly and irreversibly adsorb AcA molecules under both dry and humid conditions. In the presence of moisture, the fraction of the reversibly adsorbed AcA is promoted, which addresses the impact of water molecules with AcA on minerals. Physisorbed AcA monomer, dimer, and chemisorbed acetate are identified based on real-time surface monitoring using diffuse reflectance infrared Fourier transform spectroscopy. This study provides original data and insights into the impacts of heterogeneous interactions with mineral dust on the environmental fate of acetic acid. It also provides complete and visual mechanisms for a comprehensive understanding of the involved surface reactions. This study initiates the exploration of the heterogeneous kinetics of the fractions of reversibly and irreversibly adsorbed AcA on natural mineral dust under atmospheric conditions.

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“…Some GC material could act as a catalyst, as it was already observed for metal oxides, zeolites and carbon-based materials which can enhance the ozone-oxidation of VOCs (Brodu et al, 2012;Kastner et al, 2008;Masuda et al, 2001;Oyama, 2000). On the surface of these catalysts, the ozone reacts with the active sites (Lewis acid site) to form secondary oxidizing agents (atomic oxygen, peroxide ions, hydroxyl radicals), which subsequently react with the pollutants (Abou Saoud et al, 2019;Brodu et al, 2018;Wang et al, 2018).…”

Section: Varying Gc Parametersmentioning

confidence: 98%