Chem. J. Chinese Universities

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Internal Mixture of NaCl and Fe2O3 Serving as an Efficient Scavenger for Sulfur Dioxide

YIN Yong, CHEN Hai-Han, KONG Ling-Dong, CHEN Jian-Min*   

  1. Center for the Atmospheric Chemistry Study, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China
  • Received:2006-10-29 Revised:1900-01-01 Online:2007-07-10 Published:2007-07-10
  • Contact: CHEN Jian-Min

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

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