Oil Vapour Separation Performance Of MCM-41 Doped PVDF/PEI Hollow Fiber Adsorption Material

The volatile organic compounds(VOCs)caused by the loss of oil and gas in the process of loading and unloading of crude oil have caused serious pollution to the atmosphere.Therefore,the separation and recovery of oil and gas is the best treatment method at present.Membrane separation is one of the efficient methods for oil and gas separation and recovery.It has the characteristics of low cost and good separation effect.In order to enhance the effect of membrane separation,adsorbents were combined with membrane separation to improve the effect of separation and recovery.In this thesis,polyvinylidene fluoride(PVDF)was used as the matrix,polyether imide(PEI)was added for blending modification,and MCM-41 molecular sieve was added to prepare hollow fiber membrane,which realized the efficient adsorption of adsorption materials and membrane separation recovery.The PVDF/PEI hollow fiber membrane was characterized by XPS,XRD,FTIR,DSC,enthalpy change,etc.It was proved that PVDF and PEI were blend compatible systems and formed flumine bond.The properties of the membrane were analyzed by SEM,water contact Angle,mechanical properties,porosity,etc.The conclusions are as follows:With the increase of PEI content,large cavernous pore structure was formed in the membrane,and the connectivity was enhanced.The results show that when PEI content is 15%,the maximum strength of PVDF/PEI hollow fiber membrane is 8.04N,the elongation at break is 24.26%,the water contact Angle is 58.5°,and the porosity increases to 17.33%.The PVDF/PEI/MCM-41 hollow fiber membrane was characterized by XRD,FTIR,TG and SEM.With the doping of MCM-41,MCM-41 was evenly dispersed in the pore of the membrane,and the increase of pores led to the increase of adsorption sites,and MCM-41 was successfully doped into the hollow fiber membrane.The mechanical properties and water contact Angle of the hollow fiber membrane were tested.Compared with the original membrane,the maximum force of the hollow fiber membrane was slightly reduced to 4.00N,the elongation at break was 12.65%,and the water contact Angle was increased to 69.3°,the specific surface area increased from 438.08 m~2/g to 678.29 m~2/g.The dynamic adsorption experiment of liquefied petroleum gas was carried out,and the Y-N model was used to fit the adsorption penetration curve.It was found that with the increase of molecular sieve content,the penetration time and adsorption saturation time increased gradually,from 8min to 17min,and the adsorption saturation time increased from35min to 49min.The adsorption data of 65%PVDF/PEI/MCM-41 hollow fiber membrane for n-butane were selected for further study.Through adsorption kinetics,adsorption isotherm and other models,it is found that the adsorption behavior fits well with the Banham pore diffusion model,which is close to the experimental saturation adsorption capacity of118.29mg/g,and the correlation coefficient R~2 is 0.997,which proves that the pore diffusion adsorption in physical adsorption.The adsorption isotherm was a Type I adsorption isotherm,and the Langmuir model fitting correlation coefficient R~2 was 0.997,which further proved that the adsorption behavior was monolayer adsorption.