This title appears in the Scientific Report :
2017
Please use the identifier:
http://hdl.handle.net/2128/15734 in citations.
Please use the identifier: http://dx.doi.org/10.5194/acp-2017-610 in citations.
Multiphase Reaction of SO2 with NO2 on CaCO3 Particles. 1. Oxidation of SO2 by NO2
Multiphase Reaction of SO2 with NO2 on CaCO3 Particles. 1. Oxidation of SO2 by NO2
Heterogeneous/multiphase reaction of SO2 with NO2 on solid or aqueous particles is thought to be a potentially important source of sulfate in the atmosphere, for example, during heavily polluted episodes (haze), but the reaction mechanism and rate are uncertain. In this study, we investigated the he...
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Personal Name(s): | Zhao, Defeng |
---|---|
Song, Xiaojuan / Zhu, Tong (Corresponding author) / Zhang, Zefeng / Liu, Yingjun | |
Contributing Institute: |
Troposphäre; IEK-8 |
Published in: | Atmospheric chemistry and physics / Discussions, 610 (2017) S. 1 - 23 |
Imprint: |
Katlenburg-Lindau
EGU
2017
|
DOI: |
10.5194/acp-2017-610 |
Document Type: |
Journal Article |
Research Program: |
Tropospheric trace substances and their transformation processes |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.5194/acp-2017-610 in citations.
Heterogeneous/multiphase reaction of SO2 with NO2 on solid or aqueous particles is thought to be a potentially important source of sulfate in the atmosphere, for example, during heavily polluted episodes (haze), but the reaction mechanism and rate are uncertain. In this study, we investigated the heterogeneous/multiphase reaction of SO2 with NO2 on individual CaCO3 particles in N2 using Micro-Raman spectroscopy in order to assess the importance of the direct oxidation of SO2 by NO2. In the SO2/NO2/H2O/N2 gas mixture, the CaCO3 solid particle was first converted to the Ca(NO3)2 droplet by the reaction with NO2 and the deliquescence of Ca(NO3)2, and then NO2 oxidized SO2 in the Ca(NO3)2 droplet forming CaSO4, which appeared as needle-shaped crystals. Sulfate was mainly formed after the complete conversion of CaCO3 to Ca(NO3)2, that is, during the multiphase oxidation of SO2 by NO2. The precipitation of CaSO4 from the droplet solution promoted sulfate formation. The reactive uptake coefficient of SO2 for sulfate formation is on the order of 10−8, and RH enhanced the uptake coefficient. We estimate that the direct multiphase oxidation of SO2 by NO2 is not an important source of sulfate in the ambient atmosphere compared with the SO2 oxidation by OH in the gas phase. |