Kinetics of Heterogeneous Reaction of Sulfur Dioxide on Authentic Mineral Dust: Effects of Relative Humidity and Hydrogen Peroxide
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- 作者：Liubin Huang ; Yue Zhao ; Huan Li ; Zhongming Chen
- 刊名：Environmental Science & Technology
- 出版年：2015
- 出版时间：September 15, 2015
- 年：2015
- 卷：49
- 期：18
- 页码：10797-10805
- 全文大小：422K
- ISSN：1520-5851
文摘
Heterogeneous reaction of SO<sub>2sub> on mineral dust seems to be an important sink for SO<sub>2sub>. However, kinetic data about this reaction on authentic mineral dust are scarce and are mainly limited to low relative humidity (RH) conditions. In addition, little is known about the role of hydrogen peroxide (H<sub>2sub>O<sub>2sub>) in this reaction. Here, we investigated the uptake kinetics of SO<sub>2sub> on three authentic mineral dusts (i.e., Asian mineral dust (AMD), Tengger desert dust (TDD), and Arizona test dust (ATD)) in the absence and presence of H<sub>2sub>O<sub>2sub> at different RHs using a filter-based flow reactor, and applied a parameter (effectiveness factor) to the estimation of the effective surface area of particles for the calculation of the corrected uptake coefficient (纬<sub>csub>). We found that with increasing RH, the 纬<sub>csub> decreases on AMD particles, but increases on ATD and TDD particles. This discrepancy is probably due to the different mineralogy compositions and aging extents of these dust samples. Furthermore, the presence of H<sub>2sub>O<sub>2sub> can promote the uptake of SO<sub>2sub> on mineral dust at different RHs. The probable explanations are that H<sub>2sub>O<sub>2sub> rapidly reacts with SO<sub>2sub> on mineral dust in the presence of adsorbed water, and OH radicals, which can be produced from the heterogeneous decomposition of H<sub>2sub>O<sub>2sub> on the mineral dust, immediately react with adsorbed SO<sub>2sub> as well. Our results suggest that the removal of SO<sub>2sub> via the heterogeneous reaction on mineral dust is an important sink for SO<sub>2sub> and has the potential to alter the physicochemical properties (e.g., ice nucleation ability) of mineral dust particles in the atmosphere.