Study On The Catalytic Reduction Of NO_x By Activated Carbon Supported Manganese Oxides

With the sustained and rapid growth of China's national economy,the total amount of NO_X emissions in the process of coal utilization has gradually increased,and the air pollution problems caused by this have seriously affected the human health and the ecological environment.In order to effectively control the emission of NO_X,the research of low temperature manganese based denitration catalyst,a high removal efficiency,stable operation,low cost and long time.In this paper,different carbon based materials were used as carriers and reducing agents.The catalysts were prepared by impregnation with modified manganese based metal oxides and implanted with different metals such as Fe,K,Cu and Ce,Under the simulated flue gas atmosphere,the catalytic reduction mechanism of NO at low temperature?250??was studied by a fixed bed reactor.Experimental analysis of different valence states of manganese ion exchange,electron transfer,gas phase oxygen,lattice oxygen?hole?,NO electronic reaction and different metal ion doping and carrier type and other factors on the catalytic properties;The influence of high concentration CO on catalyst was also expounded.Characterization of the catalyst removing nitrate before and after different characterization methods,including X-ray diffraction?XRD?,scanning electron microscopy?SEM?and Fourier transform infrared spectrometer?FT-IR?on the removal of the distribution changes of crystal structure,surface morphology and structure of manganese oxide surface functional groups were analyzed before and after nitrate.The results show that the reactive oxygen species?O*?plays an important role in the denitrification reaction,its source is a lattice oxygen carried by the MnO_X itself and the formation of lattice oxygen into the gas phase oxygen oxygen hole through the capture of free electrons,on the other hand,due to the addition of metal oxides into lattice oxygen.NO is the electronic reduction reaction,firstly the dissociative adsorption of catalyst surface after oxygen atom?O?into the supplemental oxygen hole lattice oxygen,in reducing agent C,electron transfer,oxygen vacancies eventually formed by N₂ and CO₂,and the gas phase oxygen reacting with CO.It is concluded that the reduction of oxygen hole under high concentration of CO is an important reason for deactivation of the catalyst.The results of XRD analysis showed that the main active components were basically unchanged before and after the removal of the catalyst,indicating that the metal oxides played a major catalytic role in the denitration process.The SEM analysis results that biomass activated carbon rich pore structure developed,one in favor of metal active components dispersed,provide more active sites;on the other hand,is conducive to the adsorption of denitration agent on NO.The results of FT-IR showed that the carboxyl functional group acted as an active center in the denitrification reaction.In the late stage of denitrification,the lattice distortion occurs,and then the regeneration ability of O*is affected,which leads to the decrease of the denitration efficiency.Finally,the mechanism of low temperature denitration of C as reductant and manganese based catalyst was found.The mechanism of L-H and MvK existed at the same time,and the mechanism of MvK was dominant.