Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
1680-7375
5
4
2005
10.5194/acpd-5-5645-2005
http://www.atmos-chem-phys-discuss.net/5/5645/2005/
http://www.atmos-chem-phys-discuss.net/5/5645/2005/acpd-5-5645-2005.html
http://www.atmos-chem-phys-discuss.net/5/5645/2005/acpd-5-5645-2005.pdf
5645
5667
2005-08-02
Kinetics and mechanism of the uptake of N<sub>2</sub>O<sub>5</sub> on mineral dust at 298 K
S. Seisel
C. Börensen
R. Vogt
R. Zellner
Institute for Physical and Theoretical Chemistry, University Duisburg-Essen, Germany
Ford Forschungszentrum Aachen, Aachen, Germany
The heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with mineral (Saharan) dust has
been studied at <i>T</i>=298 K using a combination of Knudsen and DRIFTS cell for
kinetic and product investigations, respectively. The initial uptake
coefficient has been determined to be γ=(8.0±0.3)·10<sup>−2</sup>.
This uptake slowly saturates into a steady state uptake of
γ=(1.3±0.3)10<sup>−2</sup> suggesting that reaction of
N<sub>2</sub>O<sub>5</sub> with the mineral dust surface and hydrolysis of
N<sub>2</sub>O<sub>5</sub> on the surface take place simultaneously. Moreover, the
product investigations suggest that N<sub>2</sub>O<sub>5</sub> is irreversibly taken up
forming nitrate on the surface. The uptake rates of N<sub>2</sub>O<sub>5</sub> on
Saharan dust are large enough to influence the photo-oxidant budget of the
atmosphere.