Sulfate and ammonium formed on mineral dust can be mutually accelerated through the heterogeneous reactions of coexisting SO 2 and NH 3 . However, little is known about the underlying mechanism, especially the pivotal reactive sites. Using combined Born-Oppenheimer molecular dynamics simulations and density functional theory calculations, the results show that, compared to that of SO 2 or NH 3 alone on the γ-Al 2 O 3 surface, the increased level of formation of sulfate and ammonium can be attributed to the promoted activity of the surface-bridged hydroxyl with the coexistence of SO 2 and NH 3 . In the specific mechanism, the O and H of the surface-bridged hydroxyl group are attacked by the adjacent SO 2 and NH 3 , respectively, which directly enhances the formation of absorbed sulfite and ammonium, and indirectly facilitates the production of sulfate by oxidation of atmospheric O 2 . The proposed mechanisms can be broadly applied to other aluminum-based suspended dust particles, such as kaolinite, montmorillonite, and clay dust.
Keyphrases
- molecular dynamics simulations
- density functional theory
- room temperature
- health risk assessment
- health risk
- human health
- ionic liquid
- molecular dynamics
- polycyclic aromatic hydrocarbons
- perovskite solar cells
- heavy metals
- molecular docking
- risk assessment
- drinking water
- hydrogen peroxide
- climate change
- low birth weight
- carbon dioxide
- organic matter