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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Heterogeneous Interaction of Various Natural Dust Samples with Isopropyl Alcohol as a Probe VOC
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Heterogeneous Interaction of Various Natural Dust Samples with Isopropyl Alcohol as a Probe VOC

机译：各种天然粉尘样品与异丙醇的异质相互作用作为探针VOC

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The adsorption properties of mineral dust toward organic molecules are poorly characterized so far. Heterogeneous processes between trace gases and mineral particles can affect the oxidative capacity of the atmosphere as well as constitute additional sources or sinks for these species. The current study investigates the adsorption efficiencies of natural dust samples collected from North and West Africa, Saudi Arabia, and Arizona desert regions toward isopropyl alcohol (IPA), a common organic pollutant released in significant amounts in the atmosphere, which is used here as a probe molecule. Experiments are performed under atmospheric pressure, room temperature 296 K, over the concentration range (0.15-615) 10(13) molecules cm(-3), and in the relative humidity (RH) range (0.01-85)%. The kinetic measurements are conducted inside a U-shaped flow reactor using zero air as bath gas and a chemical ionization mass spectrometer for real-time gas-phase monitoring. Kinetic and surface parameters such as initial uptake coefficients (gamma(o)) and adsorption equilibrium constants are measured. gamma(o) is found to be independent of the IPA gas-phase concentration. However, concerning RH, gamma is independent up to ca. 20%, but a dramatic decrease is observed above that threshold implying a competition between water molecules and IPA after the formation of a water monolayer on the dust sample. These results are simulated using an empirical expression of the form gamma(RH) = gamma(dry), aRH(b) that allows the extrapolation of the uptake coefficient under any tropospheric RH conditions. Our uptake coefficient values show a linear correlation with the elemental Al/Si and Fe/Si ratios of the natural dusts studied. This was confirmed when comparing with data on inorganic species gathered from a comprehensive literature review (no such data exist for organics). To the best of our knowledge, this work is the first to demonstrate that initial uptakes are linearly correlated with the Al
机译：到目前为止，矿物粉尘对有机分子的吸附性能很差。痕量气体和矿物颗粒之间的异质过程可以影响大气的氧化能力，也可以构成这些物种的额外源或水槽。目前的研究调查了从北部和西非，沙特阿拉伯和亚利桑那州沙漠地区朝异丙醇（IPA）收集的自然粉尘样本的吸附效率，该常见的有机污染物在大气中以大量释放，其在这里使用探针分子。实验在大气压下进行，室温296k，浓度范围（0.15-615）10（13）分子cm（-3），相对湿度（0.01-85）％。动力学测量在U形流量反应器内部使用零空气作为浴气体和用于实时气相监测的化学电离质谱仪。测量诸如初始摄取系数（γ（O））和吸附平衡常数的动力学和表面参数。发现γ（o）与IPA气相浓度无关。然而，关于Rh，伽玛独立于CA. 20％，但在粉尘样品上形成水单层后，俯视截止阈值暗示水分子和IPA之间的竞争。使用γ（RH）=γ（干），ARH（B）的染色γ（RH），ARH（B）的仿真表达进行模拟这些结果，其允许在任何对流层RH条件下引入摄取系数。我们的摄取系数值显示与所研究的自然粉尘的元素Al / Si和Fe / Si比的线性相关性。与综合文献综述中收集的无机物种数据相比，这确认了这一点（有机体存在这些数据）。据我们所知，这项工作是第一个证明初始上升与AL线性相关的

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