Preparation Of Cu-MOFs Mixed Matrix Membranes For CO₂ Separation

With the increasingly prominent greenhouse effect,CO₂ capture has drawn intensive attentions.Mixed matrix membranes（MMMs）combine the advantages of inorganic materials and polymers,ease of fabrication and high permeability and selectivity in gas separations.In order to improve the CO₂ separation performance of the polyether block amide（Pebax-1657）,MMMs were prepared using three Metal-organic frameworks（MOFs）as fillers.Through the gas permeability test,the effects of filler content,feed pressure and mixed gas on the CO₂ separation performance of the membrane were investigated.Firstly,in this work,Cu（Qc）₂ was blended into Pebax-1657 to enhance performance of MMMs for CO₂ separation.It was confirmed by various characterisations that the horizontally arranged microporous nanosheets were found to strongly interact with the membrane matrix and endowed the MMMs with excellent interfacial compatibility.The Cu（Qc）₂ with a microporous structure provide high-speed channels for fast CO₂ transport and shorten diffusion pathways,both contributing toward high CO₂ permeability.The Cu（Qc）₂ with an ultra-high aspect ratio was arrange horizontally in the polymer matrix and acted as a selective barrier,thereby improved the CO₂/N₂ selectivity.When 3wt.%filler was added,the CO₂/N₂ separation performance of the MMMs was the best,and exceeded the upper limit of Robeson separation.CPL-1 was blended into Pebax-1657 to enhance performance of MMMs for CO₂ separation.The plate-like structure of CPL-1 enables crystalline nanosheets to be embedded into polymers with excellent interfacial compatibility.The microporous structure of CPL-1 can provide a path for rapid gas transfer,whilch improves the permeability of CO₂.The dual binding sites of CPL-1 and CO₂greatly improved the CO₂/N₂selectivity.When 15wt.%filler was added,the CO₂/N₂ separation performance of the MMMs was the best,and closed to the upper limit of Robeson separation.Finally,amino-functionalized NH₂-CPL-1 was blended into Pebax-1657 to enhance performance of MMMs for CO₂ separation.It was confirmed by various characterisations that microporous NH₂-CPL-1 with preferential CO₂ adsorption provided fast and selective transport channels for CO₂.And the amine group of NH₂-CPL-1 can facilitate CO₂ transport in both anhydrous and water conditions,thereby improved the CO₂ permeance and the CO₂/N₂ selectivity.When 10wt.%filler was added,the CO₂/N₂ separation performance of the MMMs was the best.When the feed gases were pure dry gas and humidified mixed gas,the gas separation performance of MMMs exceeded the upper limit of Robeson separation.Compared with the Pebax/CPL-1-10%MMMs,the CO₂ permeance and the CO₂/N₂ selectivity were both improved.This demonstrates that the NH₂-CPL-1 obtained by amino-functionalized can significantly improve the gas separation performance of MMMs.