Chemical Analysis on Polycyclic Aromatic Hydrocarbons and Nitroarenes in Atmosphere in the Area of Pan-Japan Sea, and Removal of these Organic compounds with Iron Oxides

点击翻译按钮获取中文摘要

Analysis of polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (nitroarenes) in the atmosphere in the area of Pan-Japan-Sea and removal of these organic compounds with iron oxides have been investigated. Concentration of these compounds in the atmosphere of Toyama, Kanazawa, Vladivostok and Shenyang show ed differences in the amount and the composition. The concentration of these organic compounds in Shenyang and her suburb was more than 10 times higher than that in Kanazawa. The ratio of 1-nitropyrene, one of the nitroarenes, to pyrene, one of the PAHs, suggested that main source of these compounds in Shenyang was coal combustion, though in Kanazawa and Toyama the main source is diesels-engine exhaust. Iron oxide (haematite) reacted with these compounds in helium stream at 300 〜 700 ℃ and removed them in the form of blackish particles on the iron oxide, indicating that the iron oxide catalyzed the thermal decomposition of these organic compounds. X-ray study showed that magnetite phase was observed after the reaction of haematite with the organics. This indicates that haematite was partially reduced to magnetite with the organics. By flowing air instead of helium, the organic, compounds were removed completely without forming blackish compounds on iron oxide, suggesting that oxygen in air oxidised the blackish compounds, probably the elementary carbon, and removed from the surface in the form of carbon dioxide. No phase transformation was observed from X-ray analysis of the haematite sample, indicating that haematite was not reduced to magnetite in air stream. Efficiency of removal of nitroarenes were higher than that of PAHs. Induction by nitro group may contributed to enhance the removal efficiency of PAHs.