Significant Variability in the Photocatalytic Activity of Natural Titanium-Containing Minerals: Implications for Understanding and Predicting Atmospheric Mineral Dust Photochemistry
Autor: | Devon T. McGrath, Michael J. Katz, Maya Abou-Ghanem, Anton O. Oliynyk, Sarah A. Styler, Andrew J. Locock, Laura C Matchett, Zhihao Chen |
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Rok vydání: | 2020 |
Předmět: |
Anatase
Ozone 010504 meteorology & atmospheric sciences Photochemistry engineering.material Mineral dust 010402 general chemistry 01 natural sciences chemistry.chemical_compound Environmental Chemistry 0105 earth and related environmental sciences Titanium Pollutant Minerals Atmosphere Dust General Chemistry 0104 chemical sciences Trace gas chemistry 13. Climate action Rutile Titanium dioxide engineering Environmental science Ilmenite |
Zdroj: | Environmental Science & Technology. 54:13509-13516 |
ISSN: | 1520-5851 0013-936X |
DOI: | 10.1021/acs.est.0c05861 |
Popis: | The billions of tons of mineral dust released into the atmosphere each year provide an important surface for reaction with gas-phase pollutants. These reactions, which are often enhanced in the presence of light, can change both the gas-phase composition of the atmosphere and the composition and properties of the dust itself. Because dust contains titanium-rich grains, studies of dust photochemistry have largely employed commercial titanium dioxide as a proxy for its photochemically active fraction; to date, however, the validity of this model system has not been empirically determined. Here, for the first time, we directly investigate the photochemistry of the complement of natural titanium-containing minerals most relevant to mineral dust, including anatase, rutile, ilmenite, titanite, and several titanium-bearing species. Using ozone as a model gas-phase pollutant, we show that titanium-containing minerals other than titanium dioxide can also photocatalyze trace gas uptake, that samples of the same mineral phase can display very different reactivity, and that prediction of dust photoreactivity based on elemental/mineralogical analysis and/or light-absorbing properties is challenging. Together, these results show that the photochemistry of atmospheric dust is both richer and more complex than previously considered, and imply that a full understanding of the scope and impact of dust-mediated processes will require the community to engage with this complexity via the study of ambient mineral dust samples from diverse source regions. |
Databáze: | OpenAIRE |
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