Preparation Of Al-MIL-53 Porous Material And Study On Adsorption Properties Of Benzene Series Y

Volatile organic compounds(VOCs)exist in the atmosphere,through ultraviolet light irradiation will produce photochemical smoke,this kind of smoke can cause irritation to the human eyes,and seriously affect the respiratory system,and in the long run,it can even lead to cancer.The most typical representatives are benzene,toluene,ethylbenzene and xylene,and frequent exposure to them,even at low concentrations,can cause carcinogenic effects.Therefore,the prevention and control of benzene series in VOCs is the most common research.The prevention and control of benzene series or use chemical methods such as catalytic oxidation and biodegradation to convert them into water and carbon dioxide,or use physical methods such as absorption,adsorption and condensation to remove them from the air.Among them,adsorption method can not only remove polluting gas,but also recover and reuse adsorbents and adsorbents.It is economic and environmental protection,and is the first choice for prevention and control.MOFs,as novel porous materials,have become a research hotspot due to their advantages of large specific surface area and controllable pore structure.The MOFs porous material studied in this paper is Al-MIL-53,and its innovations and main conclusions are as follows:1.Solvothermal method was used to combine Al³⁺with five organic ligand,namely terephthalic acid(BDC),nitroterephthalic acid(BDC-NO₂),amino terephthalic acid(BDC-NH₂),2,5-pyridinic dicarboxylic acid(N)and fumaric acid(FA),respectively.Five kinds of Al-MIL-53(-H,-NO₂,-NH₂,-N,-FA)were prepared.The first four aluminum sources were Al(NO₃)₃·9H₂O and Al-MIL-53-FA was Al₂(SO₄)₃·18H₂O.The XRD patterns of the samples are consistent with the standard diffraction peaks.Nitrogen adsorption test results show that Al-MIL-53-NH₂ and Al-MIL-53-N are non-porous solids,and Al-MIL-53-H are mesoporous solids,Al-MIL-53-NO₂ and Al-MIL-53-FA are microporous solids,among which Al-MIL-53-FA has the largest specific surface area,which is 1149.04 m²/g.2.Al₂(SO₄)₃·18H₂O was used as the aluminum source and combined with organic ligands BDC and BDC-NO₂,respectively.Two series of Al-MIL-53 samples were prepared by adjusting the heating temperature and reaction time.The ligand BDC was M series,and the ligand BDC-NO₂ was N series.The results of XRD,TG and FT-IR showed that all the samples of the two series were in line with the characteristics of Al-MIL-53.The crystallinity of the M-series samples was greatly affected by temperature.The XRD peak strength of the samples prepared at 180?was stronger than that at 200?and 220?.Nitrogen adsorption test showed that in the M series,the adsorption isotherm,specific surface area and pore volume of samples prepared at 180?were better than those prepared at the other two temperatures,while the N series samples were greatly affected by time.The samples prepared at 12h were generally better than those prepared at 24h and 36h in these aspects.After the sample is activated and dried,the mass of the sample is weighed.By analysis and comparison,it is concluded that the yield of N series sample is mainly affected by the heating temperature,and the yield is larger at higher temperature.However,M series shows large amount of reagent,high reaction temperature,long heating time,and more sample yield.Finally,three samples,M3-3d-180?,N2-12h-150?and Al-MIL-53-FA,were selected as adsorbents.The adsorbents were adsorbed by gravimetric steam at 30?to explore the relationship between adsorbents and adsorbents.The experimental results show that M3-3D-180?has the largest adsorption capacity for all adsorbents.3.Preparation of Al-MIL-53 Fiber Membrane.The first is the preparation of fiber membrane substrate,the use of electrospinning technology to electrospun aluminum sol fiber film,by 700?,800?,900?and 1000?calcined to form?-Al₂O₃fiber film.The results showed that?-alumina phase would not form until 800?.The microstructure of the fiber membrane showed that the fiber was continuous without breaking,and EDS showed that the weight percentage of aluminum and oxygen was more than 93%.Tensile stress test shows that the elastic modulus increases with the increase of calcination temperature.The pore size of the fiber membrane in nitrogen adsorption test is all distributed around 4 nm,and the specific surface area of the sample calcined at 800?is the largest,because the larger the specific surface area is,the more active sites can be provided in the hydrothermal reaction,so the final calcination temperature is 800?.In order to make the ligands uniformly dispersed in the reaction,a mixture of DMF and deionized water was used as the solvent.The volume contents of 8 DMFs,namely 30 vol%,20 vol%,10 vol%,0 vol%,and 9 vol%,8 vol%,7 vol%,6 vol%,were studied.Through SEM,XRD,FT-IR characterization and nitrogen adsorption test,in terms of the surface density,crystallinity,specific surface area,pore volume and pore size of the sample,the most suitable content is 9 vol%.