DRIFTS and Knudsen cell study of the heterogeneous reactivity of SO2 and NO2 on mineral dust

[摘要] The heterogeneous oxidation ofSO₂ by NO₂ on mineral dust was studied using DiffuseReflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and a Knudsen cell. Thismade it possible to characterise, kinetically, both the formation of sulfate and nitrate assurface products and the gas phase loss of the reactive species. The gas phase loss rate wasdetermined to be first order in both SO₂ andNO₂. From the DRIFTS experiment the uptakecoefficient, g, for the formation of sulfate was determined to be of the order of10^-10 using the BET area as the reactive surface area. No significant formation of sulfate was seen in theabsence of NO₂. The Knudsen cell study gave uptake coefficients of the order of10^-6 and 10^-7 for SO₂ andNO₂ respectively. There was no significant difference in uptake whenSO₂ orNO₂ were introduced individually compared to experiments in whichSO₂ andNO₂ werepresent at the same time.

[学科分类] 大气科学