1986 Fiscal Year Final Research Report Summary
Heterogeneous Photocatalytic Oxidation of Nitrogen Oxides and Sulfur Dioxide in Aqueous Solutions in Connecton with Environmental Pollution
| Project/Area Number |
60550564
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業物理化学
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| Research Institution | Chiba University |
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Principal Investigator |
HORI Yoshio Faculty of Engineering, Chiba University, 工学部, 助教授 (20114324)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Air pollution / Airborne dust / Nitrgen oxides / Sulfur dioxide, Semiconductor, Heterogeneous photocatalysis / Oxidation / 不均一系光触媒 / 酸化 / 【NO(^-_2)】 / 【NO(^-_3)】 / 【SO(^(-2)_3)】 / 光電極反応 / 酸性雨 |
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| Research Abstract |
Heterogeneous photocatalytic oxidation of <NO_2^-> was studied in connection with acid rain formation in environmental air. Typical experiments consisted of illuminating <NaNO_2> aqueous solution in a quartz tube with a xenon lamp. The aqueous solution contained semiconductor powders kept in suspension supersonically. <O_2> was bubbled into the aqueous suspensions. <NO_2^-> was quantitatively oxidized to <NO_3^-> with <O_2> under illumination in the presence of some semiconductor powders. Photoactive semiconductor powders in this reaction are <TiO_2> , ZnO, <Ag_2O> , PbO, <Bi_2O_3> , and CdS.
Photooxidation of <SO_3^(2-)> in water was also studied in the presence of some semiconductor powders. <SO_3^(2-)> is oxidized to <SO_4^(2-)> in the photocatalytic process. <TiO_2> and <Fe_2O_3> are extremely active photocatalyst for this reaction. Rates of heterogeneous photooxidation of <NO_2^-> were precisely measured in aqueous suspension of <TiO_2> (anatase), <TiO_2> (rutile), and ZnO under illumination. The reaction proceeds in zero order with respect to <NO_2^-> concentration. The rate of photooxidation of <NO_2^-> in cloud water droplets was estimated with hypothetical environmental conditions. The rate amounts to 11% <h^(-1)> for cloud water content of 0.2 g <m^(-3)> .
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