Synthesis and gas separation performance of zeolite membranes with orientation-controlled hexagonal crystals supported on γ- Al_2O_3

摘要

Zeolite membranes with the well oriented crystals were synthesized by the vapour phase transformation (VPT) of the mesostructured gel coated and spinning on γ-Al_2O_3 substrate and characterized by a series of techniques such as XRD, SEM and elemental analysis. It is shown that the orientation of crystals can be controlled by variation of synthesis atmosphere. The compactness and the thickness of the membrane can be tailored by variation of the coating method and the number of coated layers. It is very important to indicate that the alumina flat used played not only the role of the support for membrane growth, but also was used as Al source supplier to guarantee the formation of a silicoaluminate zeolite. The gas separation performances of synthesized membranes have been evaluated. The selectivity of C_3H_8/O_2 of membrane obtained by dip coating is much higher than that by spin coating due to the difference in compactness of these membranes.