Hybrid Membranes Fabricated By Incorporating Hollow Porous Materials For Pervaporative Process Intensification

Pervaporation?PV?,as a new technology for separation of liquid organic mixtures,has the advantages such as energy-saving,high-efficiency,low-carbon,and easy to amplify,which has potential industrial applications.The development of high-performance membrane materials and the improvement of membrane separation processes are key to reducing costs and realizing its commercial applications.This study aims to enhance the desulfurization performance of gasoline and optimize the process of pervaporation.Through constructing mass transfer channels via incorporating the hollow porous materials,controlling the interface morphologies between polymer and porous material,and optimizing free volume properties of the membranes,the dissolution and diffusion processes are enhanced synergistically,which improves the separation performance of the membranes.1.The amino-functionalized silicone nanotubes?AM-NT?NH₂??with the porous structure were added into polyether block polyamide?Pebax?matrix to fabricate a series of Pebax-AM-NT?NH₂?hybrid membranes.The high aspect ratio of AM-NT?NH₂?can effectively interfere with the arrangement of polymer segments,reduce the crystallinity of the membrane,and improve the free volume fraction of the membrane.Then,the hydrogen bonding between AM-NT?NH₂?and Pebax can effectively improve the interface compatibility between filler and polymer,optimizing the interface morphologies.The straight-through holes with a diameter of 1.6 nm inside the AM-NT?NH₂?provide fast mass transfer channels for the permeate molecules.In addition,A large number of pores with a diameter of 1.6 nm on the wall facilitate the permeate molecules into the inner holes.When the AM-NT?NH₂?loading was 2 wt.%,the permeation flux and enrichment factor of the hybrid membrane were 19.0 kg/?m²h?and5.5 respectively,which was 66.8%and 11.7%higher than the Pebax pure membrane,respectively.2.The monocrystalline hollow silicalite-1?HS-1?with diameters of 350 nm and200 nm were dispersed into Pebax matrix to fabricate a series of Pebax-HS-1 hybrid membranes.The HS-1 with high loading and uniform dispersion can effectively interfere with the arrangement of the Pebax polymer chain segments,and enhance the mobility of the polymer chains,lowering the crystallinity of the membrane and increasing the free volume fraction of the membrane.The molecular sieving effect for the micropores on the wall of HS-1 enhances the selectivity of hybrid membranes.Then,the hollow structure of HS-1 reduces the mass transfer resistance of the permeate molecules and shortens the mass transfer path,improving the permeation flux of the hybrid membrane.When the HS-1?200?loading was 20 wt.%,the permeation flux and enrichment factor of the hybrid membrane were 20.6 kg/?m²h?and 6.1 respectively,which increased by 82.0%and 22.7%compared with the Pebax pure membrane,respectively3.The hybrid materials of the Pebax-AM-NT?NH₂?and Pebax-HS-1 were coating onto the hollow fiber support layers to fabricate the hollow fiber composite membranes capable of achieving higher packing density.By optimizing the fabrication conditions,Pebax-HS-1?200?-20/PVDF hollow fiber hybrid composite membrane exhibits better separation performance?permeate flux 9.73 kg/?m²h?and enrichment factor 6.1?and long-term stability.Although the separation performance of the hollow fiber hybrid composite membrane is lower than that of the corresponding flat membrane hybrid membrane,its permeability coefficient is much larger than that of the flat hybrid membrane,which proves that the hollow fiber hybrid composite membrane has a good application prospect.