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HOSO2 Released from Mineral Dust: A Novel Channel of Heterogeneous Oxidation of Sulfur Dioxide during Dust Storms

Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Mineral dust has been recognized as an emerging source of radicals that may significantly influence the fate of environmental pollutants. While the production of hydroxyl (OH) radicals from an aqueous dust surface has been recently clarified, other radical-produced channels have been little understood. Here, we propose a novel channel of hydroxysulfonyl (HOSO 2 ) radical production from the aqueous surface of α-Fe 2 O 3, a ubiquitous iron mineral, during the heterogeneous oxidation of sulfur dioxide (SO 2 ). The reactive force field molecular dynamic (ReaxFF-MD) simulations and the density functional theory (DFT) calculations disclosed that the OH groups bound to the α-Fe 2 O 3 surface can oxidize the adsorbed SO 2 into HOSO 2 radicals in the presence of the surface water layer. The HOSO 2 radical can be released from the dust surface and subsequently contribute to the gaseous sulfuric acid (H 2 SO 4 ) formation. Our kinetic modeling revealed that, despite most SO 2 converting to interfacial sulfate through competing reactions on the aqueous dust surface, the abundant surface-bound OH groups and high dust particle concentration during dust storms may enable substantial gaseous H 2 SO 4 production. The level of gaseous H 2 SO 4 production from the HOSO 2 -released channel is likely comparable to that from the traditional gas-phase OH oxidation pathway. This study demonstrates that mineral-produced radicals may play a critical role in transforming atmospheric pollutants and hence modulate the impacts of mineral dust on local and regional air quality.
DOI: 10.1021/acsearthspacechem.4c00189
Language: English
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4401869248
FWCI: 0.572
Cites: 82
Cited by: 3
Related to: 10