• Title/Summary/Keyword: Regenerated metal oxide catalysts

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Decomposition of Volatile Organic Compounds Using Regenerated Metal Oxide Catalysts (폐 산업용 금속산화물계 촉매를 이용한 휘발성유기화합물의 제거)

  • Nam Seung-Won;Shim Wang-Geun;Kim Sang-Chai
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.4
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    • pp.431-439
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    • 2006
  • Catalytic oxidation of benzene, toluene and xylene (BTX) using regenerated metal oxide catalysts (ZnO-CuO, NiO, $Fe_2O_3$, ZnO, CrO) were investigated in a fixed bed flow reactor to evaluate their feasibility for the purpose of removing volatile organic compounds (VOCs). Four kinds of pre-treatment methods such as gas (air and hydrogen), acid aqueous solution, alkali aqueous solution and cleaning agent were used to find out the optimal regeneration conditions. The physico-chemical properties of the used and regenerated catalysts were characterized by BET and TPR (Temperature Programmed Reduction). The used catalysts showed high conversion ratio and the catalytic ability of toluene oxidation was in the order of ZnO-CuO>$Fe_2O_3$>NiO>ZnO>CrO. We found that the acid aqueous pre-treatment (0.1 N HNO$_3$) was the best way to enhance the catalytic activity of $Fe_2O_3$. In addition, air and hydrogen gas treatment were optimal for NiO and ZnO-CuO catalysts, respectively. Furthermore, the decomposition of BTX depends on the type of a catalyst and a gas molecule.

Effect of Water Addition on Activity of Gold Catalysts Supported on Metal Oxide at Low Temperature CO Oxidation (일산화탄소 저온 산화에서 금속산화물에 담지된 금촉매의 활성에 미치는 수분첨가의 영향)

  • Ahn, Ho-Geun;Kim, Ki-Joong;Chung, Min-Chul
    • Korean Chemical Engineering Research
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    • v.49 no.6
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    • pp.720-725
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    • 2011
  • Gold catalysts supported on metal-oxides were prepared by co-precipitation using the various metal nitrates and chloroauric acid as precursors, and effect of water addition on the catalytic activity in CO oxidation was investigated. Among the various supported gold catalysts, Au/$Co_{3}O_{4}$ and Au/ZnO catalysts showed the excellent activity for CO oxidation. Water in the reactant gas had a negative effect on the oxidation activity over Au/$Co_{3}O_{4}$ catalysts and a positive effect on that over Au/ZnO, which means the activity depends strongly on the nature of support. It was also confirmed that no significant change in the particle size of gold was observed after reaction both in dry and wet conditions. This fact suggested that the deactivated catalyst due to a carbonate species could be regenerated by water addition in the reactant gas.

The Treatment of Flue SO$_2$ Gas by Cu Powder (I) (구리 분말을 이용한 $SO_2$ 배기가스의 처리(I))

  • 정국삼;김학성;신창섭
    • Journal of the Korean Society of Safety
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    • v.1 no.1
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    • pp.27-32
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    • 1986
  • To remove sulfur dioxide from flue gas by the method of metal oxide, copper powder of average diameter $2.4\mu\textrm{m}$and $51\mu\textrm{m}$ were used in a fixed bed reactor over a, temperature range of $300^{\circ}C-500^{\circ}C$. Copper oxide reacts with sulfur dioxide producing cupric sulfate and it can be regenerated from the latter by using hydrogen or methane. Experimental results showed that the reaction rate was increased by the increase of reaction temperature in the range of $300^{\circ}C-422^{\circ}C$ and the removal efficiency of sulfur dioxide was high in case of small size copper particle. However the removal efficiency was decreased at higher temperature due to decomposition of cupric sulfate. The rate controlling step of this reaction was chemical reaction and deactivating catalysts model can be applied to this reaction. The rate constants for this reaction and deactivation are as follows : k=8,367exp(-10,298/RT) Kd=2.23exp(-8,485/RT)

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