气溶胶
反应速率常数
化学
异戊二烯
环境室
吸附
臭氧
分析化学(期刊)
光降解
气动直径
环境化学
光化学
动力学
光催化
有机化学
物理化学
物理
量子力学
共聚物
聚合物
催化作用
作者
Wolfgang Behnke,W.Th.F. den Hollander,Wolfgang Koch,F. Nolting,Cornelius Zetzsch
标识
DOI:10.1016/0004-6981(88)90341-1
摘要
A smog chamber, especially designed for the simulation of the tropospheric photochemical degradation of chemicals adsorbed on aerosol surfaces, is described. With optimum aerodynamic diameters of the aerosols (0.5 μm) and by special thermostatization of the chamber residence times of the aerosols up to 2 days in the dark and up to 1 day in the presence of simulated sun irradiation are achieved. Experiments on the degradation of simple alkanes (up to n-nonane) and aromatics in the absence and presence of aerosols (SiO2 and TiO2) are reported. Rate constants for the reactions of OH with n-alkanes from n-butane to n-tridecane are determined to be (k ± 2 σ)/10−12 cm3s−3 = 2.54 ± 0.04, 4.13 ± 0.05, 5.68 ± 0.04, 7.31 ± 0.08, 8.79 (reference value), 10.3 ± 0.2, 12.4 ± 0.2, 13.3 ± 0.2, 13.9 ± 0.2, 15.5 ± 0.2), respectively, at 300 K. These rate constant measurements and the observed concentrations of OH remain unaffected in the presence of SiO2 aerosol at mass concentrations of l mg m−3. In the presence of TiO2 at 2 mg m−3 mass concentration, the steady-state concentration of OH is enhanced by an order of magnitude. In addition, a heterogeneous photodegradation process of the hydrocarbons occurs on the surface of the TiO2 aerosol.
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