Papers by Keyword: NO Removal

Abstract: Pd catalysts and Ce_0.5Zr_0.5O₂ mixed oxides (CZ) was prepared by co-precipitation technique and their physicochemical properties were characterized by specific surface area measurements (BET), scanning electron microscope (SEM), and X-ray diffraction (XRD) techniques. CeO₂-ZrO₂ solid solutions supported with Pd are investigated as catalysts for reduction of NO. The research presented in this paper is focused on the intrinsic structure of CeO₂-ZrO₂ solid solution and catalytic behavior of NO over Pd/Ce_0.5Zr_0.5O₂ mixed oxides catalyst. The incorporation of ZrO₂ into the CeO₂ framework strongly promotes the reduction of Ce⁴⁺ in the bulk of the support. The surface area of Ce_0.5Zr_0.5O₂ was 32 m²/g after calcination in air at 1000 °C for 5 h. XRD results revealed the existence of Zr-rich phase in CZ sample. The experimental results show that the best Pd/Ce_0.5Zr_0.5O₂ catalyst yielded 97.75% NO conversion at typical reaction temperatures (280-320 C) and the high gas hourly space velocity of 15,000 h¹. The effect of the calcination temperature was also investigated, and the optimal calcination temperature was 400-500 C.

Abstract: The effects of the supply voltage, water flow rate, concentration of H₂O₂ absorption and flue gas flow rate on NO removal rate were studied. The chemical reaction mechanism of NO removal was discussed. It was concluded that the NO removal rate increased the increasing of supply voltage, water flow rate and concentration of H₂O₂, and decreased with the increasing of the flue gas flow rate on the experimental conditions. On the synergy with corona discharge and H₂O₂ solution oxidation, NO removal rate reached 60.2%.

Abstract: We analyzed the effects of several process variables on removal efficiencies of NO and SO2 by the low temperature plasma process combined with photocatalysts. The cylinder-wire type, dielectric barrier discharge process for plasma generation was used. The photocatalysts were coated onto the glass beads by dip-coating method. As the voltage applied to the plasma reactor increases, or as the pulse frequency of applied voltage increases, the NO and SO2 removal efficiencies also increase. As the initial NO concentration decreases, or as the residence time increases, the NO and SO2 removal efficiencies increase.

Abstract: In this work, the catalytic reduction of NO over activated carbon fibers (ACFs)/Ag prepared by nanoscaled Ag electroplating has been studied. It is observed that silver content on ACF surfaces increases with increasing the plating time. However, a decrease of adsorption properties, including BET’s specific surface areas and total pore volumes, in increasing the plating time is observed within the range of well-developed micropore structures. As the experimental results, the net heat of adsorption of the ACFs/Ag samples is largely influenced on the amount of silver metal, and the catalytic ability for NO removal over ACFs/Ag samples is improved in the presence of silver on the ACFs. However, the adsorption properties of the excessively silver loaded samples are significantly reduced, resulting in the decrease of the removal efficiency. Therefore, the NO removal is largely depended on silver content on ACFs, together with the results of adsorption properties of the ACFs.