抄録
Growth of MFI zeolite membranes on porous alfa-alumina substrates precoated with and without mesoporous silica sublayer was performed by in situ crystallization, with the focus on the investigation of the membrane orientation evolution. Continuous b-oriented MFI membrane can be prepared on the mesoporous silica sublayer coated substrate. After a long growth period secondary nucleation taking place in the bulk reaction solution results in randomly oriented membrane with overgrowth behavior. Discrete b-oriented crystals are deposited on the uncoated alfa-alumina substrate at the initial stages. As the crystallization proceeds, a membrane with a randomly oriented and eventually [hoh]-oriented top layer can be obtained. The chemistry property and the surface smoothness of the substrates are suggested to have significant effects on the membrane orientation during growth process.
