Mixed Matrix Membrane Incorporated With Inorganic Filler For Improved Polyetherimide Gas Separation Membrane

Natural gas is distinguished as a green and valuable alternative energy resource.However,natural gas usually contains a considerable amount of impurities.The impuritie must be removed in order to overcome process pipeline and equipment corrosion-related problems.lt has been found that membrane technology is a simple and efficient green treatment method to remove the impuritie.The mixed matrix membrane emerged,while combines the advantages of overcoming the limitations of the permeability and selectivity.For the first stage,MOFs?ZIF-8?were incorporated in polyetherimide?PEI?membrane to improve the CO₂/CH₄ permeability and selectivity.SEM image of mixed matrix membrane show that the particles are dispersed evenly in the organic phase with low ZIF-8 loading,When the filling volume is higher,the ZIF-8 in the membrane distribution begin uneven.In the following experiment,the effects of gas permeation coefficient and separation factor of mixed matrix membranes were investigated under different solvents and different operating conditions.When the solvent is DCE,the mixed matrix membrane exhibits the best performance with 25%ZIF-8 loading,the CO₂/CH₄ selectivity was 17.00,and the gas permeability coefficient is better than the pure membrane,CO₂ permeability reachs 62.93 Barrer.When the solvent is NMP,the membrane permeability coefficient is larger than that of the DCE solvent,but the CO₂/CH₄ separation coefficient drops.In the same way,with the increase of pressure,the permeation of the pure membrane and MMM increase,but CO₂/CH₄ separation factor decrease slightly.In terms of temperature,the permeability coefficient of CO₂ and CH₄ gases and separation factor increase with the increase of temperature.Next,ZSM-5 was incorporated in polyetherimide membrane?PEI?to improve the CO₂/CH₄ permeability and selectivity.In the following experiment,the effects of gas permeation coefficient and separation factor of mixed matrix membranes were investigated under different solvents and different operating conditions.When the solvent is DCE,the mixed matrix membrane exhibits the best performance with 20%ZSM-5 loading,the CO₂/CH₄ selectivity was 21.3,and the gas permeability coefficient is better than the pure membrane,CO₂ permeability reachs 61.23 Barrer.When the solvent is NMP,the membrane permeability coefficient is larger than that of the DCE solvent.In the same way,with the increase of pressure,the permeation and CO₂/CH₄ separation factor of MMM increase.In terms of temperature,the permeability coefficient of CO₂ and CH₄ gases and the separation factor increase with the increase of temperature.Comparing mixed matrix membranes that prepared by the two different filler,it was found that the separation factor and permeability coefficient of ZSM-5/PEI membrane are larger than that ZIF-8/PEI membrane.When the solvent is DCE,the former CO₂ permeability coefficient is higher than the latter;the separation factor increases 23.5%.Therefore,the ZSM-5/PEI mixed matrix membrane has better performance.With the increase of pressure,the separation factors of ZIF-8/PEI mixed matrix membranes decreases,but the ZSM-5/PEI mixed matrix membrane has a contrary conclusion.The particle surface of ZSM-5 and ZIF-8 was modified by using a couple agnet to improve the CO₂/CH₄ selectivity was investigated.The study found that the ZIF-8 and ZSM-5 that modified by using a couple agnet in the mixed matrix membrane are more evenly dispersed in organic phase.In the following experiment,it was found that the separation factor of the modified mixed matrix membrane was higher,but the permeabil ity coefficient of gas decreased.With the increase of the pressure,the permeability coefficient and the separation factor of the modified mixed matrix membrane are increased.