Effect of Sulfuric Acid on the Uptake of Sulfur Dioxide on Soot
Abstract
The uptake of SO2 on soot may lead to the formation of sulfuric acid on the soot. The sulfuric acid then can affect the further uptake of SO2 on the soot. We are interested in the effect of submonolayer H2SO4 on the uptake of SO2. We measured the uptake of SO2 on n-hexane soot as a function SO2 pressure (10-7 to 10-4 Torr) and sulfuric acid coverage between -140\deg and -120\deg C. We generate sulfuric acid by adsorbing varying amounts of SO3 on soot, covering the SO3 with a thick layer of condensed H2O, and heating to 193 K to react the SO3 and H2O and to remove the excess H2O. The sulfuric acid coverage is in the range of monolayer or sub-monolayer. Adsorption of SO2 on soot with and without the sulfuric acid shows that the acid reduces the SO2 uptake by a factor of two or more. Varying the amount of acid has little effect on uptake. However, increasing the thickness of the soot substrate causes a significant increase in SO2 uptake.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM...A51B02S
- Keywords:
-
- 0305 Aerosols and particles (0345;
- 4801);
- 0317 Chemical kinetic and photochemical properties