The Study On Combined Denitration Performance At Low Temperature By Mofs And Composited TiO₂

With the increasingly serious air pollution problem,researchers focus on the development of new and efficient materials to improve the ability to treat pollutants.In this experiment,MOFs and composited TiO₂ were prepared to treat high concentration NO_X,and the reaction conditions and mechanism were investigated.The materials were characterized by XRD,BET,SEM,TGA,photocurrent and others.Microwave heating has been introduced to prepare MOFs,which shortened the preparation time to 4 hours and increased the productivity.In NH₃-SCR experiment,Uio-66 shows the best denitration performance.When the doping molar ratio of Cu is10%,the denitration efficiency of the concentration of 1093.44 mg/m³ NO_X can be increased by 33%at 200?.XRD and SEM characterizations show that MOFs with complete structure has been successfully prepared.BET and TGA results show that the specific surface area and thermal stability of Uio-66 were effectively improved by the doping of copper.After compared,the composited TiO₂ prepared by microwave method with different composite elements and modes.The composited ZnO-TiO₂ prepared by sol-sol method was screened out through photocatalytic denitration experiment.The visible photocatalytic denitration efficiency of 6.83 mg/m³ NO_X is 85%,32%higher than that of pure TiO₂,and for concentration to 13.67 mg/m³ its efficiency can still reach 66%,if NH₃ is added?NH₃:NO_X,1:1?its efficiency can up to 96%.The whole reaction can be divided into two parts:adsorption and photocatalysis.Photoelectrons can reduce NO₂ to N₂.XRD and BET characterization show that anatase phase composited ZnO-TiO₂ has been successfully prepared.The photocurrent result shows that the visible light responsiveness has been greatly improved after composite,which is consistent with the experimental results.The combined use of NH₃-SCR and photo-catalytic denitration was used to treat high concentration NO_X.When the concentration of NO_X is between 700 with 2700mg/m³,the overall denitration efficiency can reach 98%or more,which indicates that the application scope of combined treatment is wider.So it has higher environmental and economic benefits than using the two methods alone.