Synthesis of MFI Zeolite Membranes by Cross-Flow Seeding Procedure

Zeolite membranes have attracted interest in many separation processes owing to their crystalline structure and to their pore diameters close to molecular size of different species. The most used methods for their preparation are the in situ and the secondary growth. The last one presents two steps: seeding and growth. In the first step, seeds are deposited on the support surface followed by a crystal growth. More controllable seeding involves the filtration of a zeolite water slurry through a flat support [1]. Nevertheless, coverage uniformity problems can happen when tubular supports are used. This problem can be overcame using a seeding where the cross-flow filtration is combined with the rotation and tilting of the support [2]. In this work for the first time was demonstrate the possibility to prepare MFI zeolite membranes by using the new cross-flow seeding procedure. Morphology and thickness of the zeolite layer were observed by scanning electron microscopy. Topology of the crystals were examined by X-ray diffractometry. The separation properties were also investigated