| Membrane separation with advantages of high efficiency,simple step,low cost,low-energy,non-pollution,was widely used in chemical industry,medicine,metallurgy,environmental protection and food fields.In this paper,alumina was used as the carrier,and its surface was modified by silane coupling agent.Then the SAPO-34 zeolite membranes were synthesized on the carrier surface by hydrothermal method and covalent bonding-secondary growth method.The separation performances of SAPO-34 zeolite membrane were evaluated by gas permeation test.The research results are listed as follows:1.The SAPO-34 zeolites were successfully prepared by the traditional hydrothermal method.The morphology and structure of SAPO-34 zeolites were characterized by scanning electron microscopy?SEM?and transmission electron microscopy?TEM?.The results showed that the prepared SAPO-34 zeolites were cube-shaped,with high crystallinity.The average crystal size of it was 250 nm.2.The alumina carrier surface was modified with 3-aminopropyltriethoxysilane?KH-550?and?-methacryloxypropyltrimethoxysilane?KH-570?.Then the SAPO-34 zeolite membranes were prepared on the surface modified alumina carrier by covalent bonding-secondary growth method.By SEM and XRD characterization,it was indicated that the SAPO-34 zeolite membranes prepared in this method were uniform,dense and with non-defects.3.H2/CO2 mixed gas separation test were taken to evaluate the properties of SAPO-34zeolite membranes.Compared with the SAPO-34 zeolite membrane prepared by the traditional method,the separation performance of the SAPO-34 zeolite membrane prepared by covalent bonding-secondary growth method was much better.Under the condition of298 K and a feed pressure of 0.1 MPa,the H2/CO2 separation factor of SAPO-34 zeolite membrane prepared by covalent bonding-secondary growth method was 6.2,4.4 times of that of traditional synthesis.At the same time,CO2 permeability is also up to 1.76×10-7mol·m-2·s-1·Pa-1,which is 7.6 times the traditional synthetic method. |
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