Preparation/Characterization And Application Of Polyimide Hybrid Membrane

In order to improve the gas permeability of polyimide membrane materials,Three kinds of PI-ZrO₂,PI-Al₂O₃ and PI-uio-66 polyimide hybrid films were designed and prepared.,which effectively improved the gas permeability of polyimide membrane materials.The main contents of this paper are as follows:Firstly,PI-ZrO₂,PI-Al₂O₃ and PI-uio-66 polyimide hybrid membranes were prepared by blending method and thermal imidization method.Among them,the mass fractions of Al₂O₃ and ZrO₂ nanoparticles are 1%,2%,3%,4%,5%,respectively,and the mass fractions of zirconium metal organic skeleton compounds?uio-66?were 1%,5%,10%,15%,20%.The structure and thermal properties of hybrid membranes were characterized by infrared spectroscopy,field emission scanning electron microscopy,thermogravimetric-differential gravity analyzer and automatic physical adsorption apparatus.The results showed that ZrO₂ and Al₂O₃nanoparticles bonded with polyimide polymer to form a new organic-inorganic network structure.The formation of this structure made the pore size distribution of polyimide film uniform while maintaining good thermal stability.However,zirconium metal organic skeleton compound?uio-66?and polyimide polymer were only physically mixed,Uio-66 is uniformly embedded in the polyimide polymer to form a dense microporous structure,uio-66 is uniformly embedded in polyimide polymer to form a dense microporous structure,which made the polyimide film maintain good thermal stability and increased the pore size.Gas permeability of polyimide hybrid membranes was tested with pure CO₂,CH₄ and N₂ as test gases.The effects of blend particle content and pressure on gas permeation selectivity of hybrid membranes were studied.The following conclusions are drawn:1.With the increase of the content of blend particles,the permeability of CO₂,CH₄ and N₂ increases,and the gas selectivity of CO₂/CH₄ increases first and then decreases.2.When the mass fraction of ZrO₂ is 3%,the gas permeation selectivity of PI-ZrO₂ hybrid membrane is the best,The separation factor of CO₂/CH₄is 19.2.Compared with the traditional polyimide membrane,the gas permeability coefficients of CO₂,CH₄ and N₂ increase to 7.4,18.8 and 18.1times respectively.3.When the mass fraction of Al₂O₃ nanoparticles is 4%,the gas permeability of PI-Al₂O₃ hybrid membrane is the best,The separation factor of CO₂/CH₄ is 16.2.Compared with the traditional polyimide membrane,the gas permeability coefficients of CO₂,CH₄ and N₂ increase to 8.0,24.1 and76.6 times respectively.4.When the mass fraction of uio-66 is 10%,the maximum separation factor of CO₂/CH₄ in PI-uio-66 hybrid membrane is 20.6.Compared with the traditional polyimide membrane,the gas permeability coefficients of CO₂,CH₄ and N₂ increase to 4.4,10.4 and 31.9 times respectively.5.With the increase of pressure,the gas permeability of PI-ZrO₂ and PI-Al₂O₃ hybrid membranes increases gradually,while that of CH₄ and N₂almost remains unchanged,while that of PI-uio-66 hybrid membranes does not change with the increase of pressure.The modified polyimide membrane has good permeation separation performance of CO₂ and CH₄.It can be used for the separation of CO₂ and CH₄ in biogas,and effectively improves the separation efficiency of CO₂ and CH₄.