Kinetics and mechanism of the uptake of N₂O₅ on mineral dust at 298 K

S. Seisel (1) , C. Börensen (2) , R. Vogt (2) , R. Zellner (1)

1 Institute for Physical and Theoretical Chemistry
2 Ford Forschungszentrum Aachen

The heterogeneous reaction of N₂O₅ with mineral (Saharan) dust has been studied at T=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 ?=(8.0±0.3)·10^?2. This uptake slowly saturates into a steady state uptake of ?=(1.3±0.3)10^?2 suggesting that reaction of N₂O₅ with the mineral dust surface and hydrolysis of N₂O₅ on the surface take place simultaneously. Moreover, the product investigations suggest that N₂O₅ is irreversibly taken up forming nitrate on the surface. The uptake rates of N₂O₅ on Saharan dust are large enough to influence the photo-oxidant budget of the atmosphere.

Domaines: Océan, Atmosphère

S. Seisel, C. Börensen, R. Vogt, R. Zellner. Kinetics and mechanism of the uptake of N₂O₅ on mineral dust at 298 K. Atmospheric Chemistry and Physics Discussions, 2005, 5 (4), pp.5645-5667. ⟨hal-00301682⟩