Research On Simultaneous Desulfurization And Denitrification By MeOx/GP And Modified Catalysts

"Near zero emissions" set targets for emissions of soot,sulphur dioxide and nitrogen oxides below 1 mg/m3,10 mg/m3 and 25 mg/m3 respectively.The usage of carbon as adsorbent and catalyst is considered to be very promising in the development of various flue gas cleaning technologies.The technology of simultaneously controlling SO2 and NO emissions based on carbon materials not only reduces the cost of environmental protection,but also realizes the resource recovery of sulfur and nitrogen.However,adsorption and catalytic reaction mechanism of carbon based materials is also lack enough understanding.This paper,with graphene load metal oxide catalyst as the research object to carry out the experimental and theoretical study,reveals different graphene catalytic material under the action of the desulfurization denitration reaction mechanism and the synergy between the graphene carrier and active component features.First,graphene was prepared by liquid phase mechanical stripping and graphene oxide was prepared by improved Hummers method using KMnO4 as oxidant.Samples were characterized by scanning electron microscope,XPS and AFM.The results show that the prepared graphene nanosheet has large geometric dimensions and is mainly composed of single layer and double layer.Graphene oxide exist a large amount of oxygen-containing groups,can be highly dispersed in aqueous solution or other organic solvents,further blending with much of the material such as metal oxide,made from a variety of modified graphene base metal oxide catalyst and load sample.A set of adsorption performance test and catalyst activity test platform were set up.Different graphene based materials on adsorption was studied in detail the influence of oxidation performance,including oxygen-containing functional groups,nitrogen functional groups,different pyrolytic temperature,flue gas SO2 and H20,load with different metal oxide and add KC1 simulating biomass carbon composition factors such as adsorption oxidation performance impact of sample preparation.The results show that the adsorption and desorption of nitrogen and sulfur pollutants can be improved in diffrenent degrees by surface modification of graphene or adding some metal oxides.On the basis of experimental research,set up different modified graphene model,using DFT Materials Studio software DMol3 module,to study the different modification methods on the reaction of NO and SO2 adsorption and molecular features.It was found that the adsorption energy of go to SO2 molecules(Eads)was much higher than that of NO molecules,and the existence of SO2 hindered the adsorption of NO.The-OH group can oxidize the NO molecule,or even the SO2 molecule,while the-COOH group cannot.The results showed that the specific proportion of HO-G[? HO-Gdef]content was increased after the oxygen content of graphene surface was reduced after pyrolysis at a proper temperature,which could promote the adsorption and oxidation of graphene samples with oxygen-containing functional groups.In graphene modified model,on the basis of building the load model of manganese oxide catalyst,further study of NO and SO2 surface energy absorption and adsorption material,discusses the NO and SO2 molecules and graphene fund is chemical adsorption between oxide formation.The mechanism of H2O2 catalytic oxidation of NO and SO2 under the action of modified graphene oxide catalyst was studied.Results show that interaction between H2O2 and MnO/Gdef,directly decompose generate oxygen free radicals,OH,surface oxidation of NO and SO2 follow two steps reaction mechanism of oxidation of NO and SO2 of nitrite/sulfite acid->nitric acid/sulfuric acid;The mechanism of catalytic oxidation of NO by MnO/HyG and NO by MnO/Gdef SO2 is similar,but the reaction mechanism of catalytic oxidation of S02 by MnO/HyG is:MnO/HyG-OH + SO2->MnO/HyG SO2 OH? MnO/HyG(SO2 OH? MnO/HyG-H + SO3;In the MnO/CyG system,the efficiency of electron-hole transfer between MnO and graphite sheet layer is lower than that of MnO/Gdef and MnO/HyG.Load of iron oxide catalyst model was constructed,further study of NO and SO2 surface energy absorption and adsorption material,discusses the NO and SO2 molecules and graphene fund is chemical adsorption between oxide formation.The adsorption capacity of NO and SO2 on Fe2O3/Gdef,Fe2O3/HyG and Fe2O3/CyG surface decreases with the oxidation of graphene.The results of NO and SO2 oxidation reactions catalyzed by different catalysts showed that the adsorption capacity of H2O2 on Fe2O3/Gdef,Fe2O3/HyG and Fe2O3/CyG surface decreased with hydroxylation and carboxylation,and the adsorption capacity of H2O2 could not be decomposed directly.However,the presence of Fe2O3/Gdef,Fe2O3/HyG and Fe2O3/CyG catalytic,free radicals formed in the regulation of the H2O2 decomposition reaction equilibrium,to a certain extent promoted the formation of free radicals,NO and SO2 oxidation reaction was happened to promote role.H2O2 oxidizes NO on the surface of Fe2O3/Gdef as adsorbed nitrite and releases a hydroxyl radical.On the surface of Fe2O3/HyG,it oxidizes NO as free nitrous acid molecules,and on the surface of Fe2O3/CyG,it oxidizes NO as free nitrous acid molecules.Similarly,Fe2O3/Gdef,Fe2O3/HyG and Fe2O3/CyG can directly adsorb H2O2 to oxidize SO2 as sulfuric acid molecule on the surface.The adsorption and reaction mechanism of NO and SO2 can be adjusted by different modification of graphene,so as to guide the rational preparation of carbon base catalyst for the desulfurization and denitrification of flue gas.The results of this study can also provide a reference for the study of structure,electron properties,surface adsorption and reaction of graphene-metal oxide catalytic materials.Finally,innovative proposed design in biomass charcoal burning pool at the bottom of the furnace,to achieve make carbon(or not)modles change,realize large-scale biomass carbon adsorbent preparation work.Adding MeOx into the granulation process can improve the activity of adsorbent in one step,realize the combination of carbon carrier and catalytic component,and improve the removal efficiency of sulfur-nitrogen pollutants.