Influence Of Atmosphere Conditions On Denitration Performance Of Mn-Fe/AC Catalyst Irradiated By Microwave

This thesis is based on the research team’s previous research on the effect of metal oxide loading on microwave-induced denitration of activated coke,using manganese oxide and iron oxide as catalysts,and activated coke as reducing agent and catalyst carrier.The effects of iron oxide loading and SO₂,H₂O,O₂,and CO₂ on the denitration efficiency of microwave-irradiated catalysts were studied.Various characterization methods were used to characterize and analyze the catalysts,and the following main conclusions were obtained:（1）Compared with manganese-based catalysts,the denitration efficiency of Mn-Fe/AC catalysts supported by bimetallic oxides is significantly improved.The 5Mn3Fe/AC with an iron oxide loading of 3wt%has the best denitration efficiency.Under 200W microwave power,the average denitration efficiency is 98.60%.The loading of iron oxide makes the pore structure of activated coke developed,the content of basic functional group C=O increases,the carbon active sites increase,and the content of Mn²⁺on the surface of activated coke increases,which contributes to the progress of the NO reduction reaction.（2）As the concentration of SO₂ in the atmosphere increases,the denitration efficiency and microwave discharge intensity of 5Mn3Fe/AC decrease,and the amount of CO generated increases.The peak intensity of the C=C functional group on the surface of the activated coke increases,and the microwave-induced discharge of the activated coke forms a functional group that is conducive to SO₂ adsorption.XPS shows that after denitrification in an atmosphere containing SO₂,the content of Mn²⁺decreases,and Fe₂（SO₄）₃ is formed.The metal active sites on the surface of the activated coke are occupied,which affects the progress of the NO catalytic reduction reaction.（3）The presence of H₂O reduces the denitration efficiency and microwave-induced discharge intensity of metal oxide-loaded activated coke,increases the amount of CO generated,and activates the pore structure of activated coke by gasification reaction.FT-IR shows that in the process of denitration,water molecules are decomposed into OH radicals and adsorbed on the surface of activated coke.Part of OH combines with NO to form NO₃^2-,and NO₃^2-combines with metal ions to form nitrate.（4）With the increase of the O₂ content at the reaction inlet,the denitration efficiency of5Mn3Fe/AC increases,and the average discharge intensity and CO generation increase.FT-IR shows that microwave discharge under O₂ atmosphere can accelerate the decomposition of oxygen-containing functional groups and the formation of C=C functional groups.（5）With the increase of CO₂ content,the denitration efficiency of 5Mn3Fe/AC decreases slightly,and the discharge intensity decreases.During the reaction,C and CO₂ undergo gasification reaction,the average amount of CO produced increases,the specific surface area of activated coke increases from 159.579 m²/g to 207.123 m²/g,and the pore structure develops.