关键词: 矿尘与海盐混合物, 矿尘与海盐混合物, 红外漫反射, 红外漫反射, 复相反应, 复相反应, 吸附常数, 吸附常数, 硫酸盐, 硫酸盐

Abstract: Internal mixing of sea-salt and mineral dust is often observed in coastal regions and the adjacent marine boundary layer, but the influence on atmospheric chemistry is not well known. In this paper the investigation of the reaction of SO₂ on the surface of mixed particles composed of Fe₂O₃ and NaCl was made by means of DRIFTS and XPS and the corresponding reactive uptake coefficients were calculated. The main products were sulfate/bisulfate and the minor product was sulfite/bisulfite. It was shown that the reaction rates with SO₂ are correlated with zero order kinetis. The reactive uptake coefficient for SO₂ oxidation by O₂ was determined. Different proportions of NaCl resulted in distinct reaction abilities. With increasing the proportion of NaCl, the BET uptake coefficient increased at first and decreased afterwards. When NaCl accounted for 70% of the mixture, the BET uptake coefficient accounted to 4.62×10^-6, which is 8.07 times as much as that of pure α-Fe₂O₃(5.72×10^-7). The FeCl₂-SO₃^- formed and served as a temporal reservoir of sulfur species, which can be used to explain the experiment results. The mixture shows a significant capacity to scavenge SO₂, it is important to implicate the heterogeneous gas-to-particle conversion mechanism of atmospheric SO₂, reevaluate the impact involving mineral dust mixed with sea salt and the influence of the aerosol radiative forcing and the sulfate cooling effect.

Key words: NaCl mixed with hematite, NaCl mixed with hematite, DRIFTS, DRIFTS, Heterogeneous reaction, Heterogeneous reaction, Uptake coefficient, Uptake coefficient, Sulfate, Sulfate