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| Titel |
Kinetics and mechanism of heterogeneous oxidation of sulfur dioxide by ozone on surface of calcium carbonate |
| VerfasserIn |
L. Li, Z. M. Chen, Y. H. Zhang, T. Zhu, J. L. Li, J. Ding |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 9 ; Nr. 6, no. 9 (2006-06-29), S.2453-2464 |
| Datensatznummer |
250003971
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| Publikation (Nr.) |
 copernicus.org/acp-6-2453-2006.pdf |
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| Zusammenfassung |
| Sulfate particles play a key role in the air quality and the global
climate, but the heterogeneous formation mechanism of sulfates on
surfaces of atmospheric particles is not well established.
Carbonates, which act as a reactive component in mineral dust due to
their special chemical properties, may contribute significantly to
the sulfate formation by heterogeneous processes. This paper
presents a study on the oxidation of SO2 by O3 on
CaCO3 particles. Using Diffuse Reflectance Infrared Fourier
Transform Spectroscopy (DRIFTS), the formation of sulfite and
sulfate on the surface was identified, and the roles of O3 and
water in oxidation processes were determined. The results showed
that in the presence of O3, SO2can be oxidized to sulfate
on the surface of CaCO3 particles. The reaction is first order
in SO2 and zero order in O3. The reactive uptake
coefficient for SO2 [(0.6–9.8)×1014 molecule
cm-3] oxidation by O3 [(1.2–12)×1014
molecule cm-3] was determined to be
(1.4±0.3)×10-7 using the BET area as the
reactive area and (7.7±1.6)×10-4 using the
geometric area. A two-stage mechanism that involves adsorption of
SO2 followed by O3 oxidation is proposed and the
adsorption of SO2 on the CaCO3 surface is the
rate-determining step. The proposed mechanism can well explain the
experiment results. The atmospheric implications were explored based
on a box model calculation. It was found that the heterogeneous
reaction might be an important pathway for sulfate formation in the
atmosphere. |
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