Interactions between Heterogeneous Uptake and Adsorption of Sulfur Dioxide and Acetaldehyde on Hematite.
Interactions between Heterogeneous Uptake and Adsorption of Sulfur Dioxide and Acetaldehyde on Hematite.
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DOI：
10.1021/acs.jpca.5b01359
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发表时间：
2015-04
期刊：
影响因子：
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通讯作者：
Xi Zhao;Lingdong Kong;Zhenyu Sun;Xiaoxia Ding;T. Cheng;Xin Yang;Jianmin Chen
中科院分区：
文献类型：
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作者：
Xi Zhao;Lingdong Kong;Zhenyu Sun;Xiaoxia Ding;T. Cheng;Xin Yang;Jianmin Chen
大气中的二氧化硫和有机醛无处不在，通常与矿物粉尘气溶胶有关。这些物种中的一种在矿物气溶胶上的异相吸收和吸附可能会潜在地改变颗粒的性质，并进一步影响其他物种在涂层颗粒上随后的异相反应。本文利用原位漫反射红外傅里叶变换光谱(DRIFT)研究了二氧化硫和乙醛在赤铁矿上的非均相吸收和吸附的相互作用。结果表明，α-Fe_2O_3上SO2的预吸附能显著阻碍CH3CHO后续的非均相氧化生成乙酸酯，而CH3CHO的预吸附显著抑制了大量SO_2在α-Fe_2O_3表面的非均相反应，对少量SO_2的吸附影响不大。CH3CHO预吸附的α-Fe_2O_3上SO_2的非均相反应将颗粒表面存在的乙酸根转化为化学吸附的乙酸根，从而增强了吸附SO_2后的表面酸性。在这些过程中，不同的表面羟基表现出不同的反应活性。讨论了这项研究的大气影响。
Sulfur dioxide and organic aldehydes in the atmosphere are ubiquitous and often correlated with mineral dust aerosols. Heterogeneous uptake and adsorption of one of these species on mineral aerosols can potentially change the properties of the particles and further affect the subsequent heterogeneous reactions of the other species on the coating particles. In this study, the interactions between heterogeneous uptake and adsorption of sulfur dioxide and acetaldehyde on hematite are investigated by using in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) at room temperature. It is found that the preadsorption of SO2 on α-Fe2O3 can significantly hinder the subsequent heterogeneous oxidation of CH3CHO to acetate, while the preadsorption of CH3CHO significantly suppresses the heterogeneous reaction of large amounts of SO2 on the surface of α-Fe2O3 and has a little influence on the uptake of small amount of SO2. The heterogeneous reactions of SO2 on α-Fe2O3 preadsorbed by CH3CHO change the existing acetate on the particle surface into chemisorbed acetic acid, for the enhancement of surface acidity after the uptake of SO2. During these processes, different surface hydroxyl groups showed different reactivities. Atmospheric implications of this study are discussed.