Well-aligned SAPO-5 membrane: preparation and characterization

Membranes of well-aligned SAPO-5 crystals were grown on floating anodic alumina by a two-step microwave hydrothermal synthesis. Various sets of samples with different silicon contents in reactant gels and different reaction times in secondary microwave hydrothermal heating were studied. The degree of preferred orientation along the c-crystal axis of the AFI structure and the zeolite coverage on alumina support were analyzed by XRD and SEM. FTIR microscopy was employed to study lattice vibrations in membranes of aligned AFI crystals as well as in AFI single crystals, while secondary ion mass spectroscopy and Si-29 MAS NMR were used to determine the Si distribution and its state in SAPO-5 products. (C) 1998 Elsevier Science B.V. All rights reserved.