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Title: | 銅錳氧化物修飾中孔氧化矽以控制模擬燃煤煙氣中Hg(0)與NO研究 Copper-Manganese Oxides Supported by Mesoporous Silica for Control of Hg(0) and NO in Simulated Coal-Combustion Flue Gases |
Authors: | Cong-Jhen Lin 林聰鎮 |
Advisor: | 席行正 |
Keyword: | 二氧化矽剝蝕法,汞,氮氧化物,銅錳觸媒,中孔二氧化矽,燃煤煙氣, Silicate-exfoliation method,mercury,NOx,Cu-Mn oxides,mesoporous silica,coal-combustion flue gases, |
Publication Year : | 2018 |
Degree: | 碩士 |
Abstract: | In Taiwan, coal-fired power plants (CFPPs) are the primary emission sources of NOx and mercury. NOx caused environmental problem like the photochemical smog, acid rain and secondary PM2.5. Mercury has been received great concerns because of the high toxicity and stability in the atmosphere. Because the presence of metallic species could improve the activity of porous catalysts, the CuOx-MnOx/SiO2 was prepared through the silicate-exfoliation method for control of elemental mercury (Hg0) and NO in simulated coal-combustion flue gases in this study. Compared with the co-precipitation method, the silicate-exfoliation method could cause a high metal loading with uniform metal dispersion on the silica surface. The specific molar ratios of Cu/Mn/Ce = 5/5/0, 2/8/0, 8/2/1, and 6/4/1 were chosen to incorporate with the adequate amount of silicate (molar ratio of metal oxides/silicate = 1). The 77K N2 adsorption results indicated that the presence of Cu and Mn oxides increased the specific surface area due to the synergistic effect between Cu-Mn oxides and silicates; additionally, this effect caused the uniform dispersion of metal oxides on the catalyst surface, confirmed by the XRD results. NH3-TPD results showed that Cu2Mn8 had the largest desorption peak area, possibly leading to the sample’s greater performance in NO control. The TEM diagram proved the reconstruction of the surface structure after the incorporation of metal oxides with SiO2. H2-TPR results showed that a single reduction peak was observed on the tested materials except for Cu2Mn8. This reduction peak was attributed to the eletronic transfer between the Cu and Mn cations. The similar synergistic effect resulted in the higher Mn4+ ratio shown in the XPS results.
Cu2Mn8 showed the best NO removal efficiency at the temperature range from 250 to 350°C. The Hg0 removal efficiency of Cu2Mn8 was around 30% after the 15-h test. The modification of cerium did not show to improve the NO and Hg0 removal. However, the great resistance in SO2 poisoning was shown over the Cu6Mn4Ce1; in contrast, the addition of cerium enhanced the NO removal efficiency at 250-350°C. These experimental results suggest that the synergistic effect of Cu-Mn mixed oxides in silicate leads to the higher specific area and well dispersion of metal oxides, but inhibits the activity of manganese oxides. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70890 |
DOI: | 10.6342/NTU201802542 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 環境工程學研究所 |
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ntu-107-1.pdf Restricted Access | 6.06 MB | Adobe PDF |
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