Preparation and characterization of hollow fibers of silicalite-1

Hollow fibers consisting solely of silicalite-1 were prepared by a novel method consisting of four basic steps. Carbon fibers were first surface modified to facilitate adsorption of colloidal seed crystals of silicalite-1. Such particles were then adsorbed as a monolayer on the fiber surface and ind...

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Bibliographic Details
Published in:Zeolites 1996-11, Vol.17 (5), p.408-415
Main Authors: Valtchev, Valentin, Schoeman, Brian J., Hedlund, Jonas, Mintova, Svetlana, Sterte, Johan
Format: Article
Language:English
Subjects:
Chemical Sciences
Chemical Technology
Chemistry
crystallization
Exact sciences and technology
General and physical chemistry
Hollow fibers
Ion-exchange
Kemisk teknologi
silicalite-1
Surface physical chemistry
Zeolites: preparations and properties
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Summary:Hollow fibers consisting solely of silicalite-1 were prepared by a novel method consisting of four basic steps. Carbon fibers were first surface modified to facilitate adsorption of colloidal seed crystals of silicalite-1. Such particles were then adsorbed as a monolayer on the fiber surface and induced to grow into a continuous film of intergrown crystals of silicalite-1. Finally, the carbon fiber used as a template was removed by calcination in air, yielding hollow fibers of silicalite-1. Hollow fibers were prepared in two experimental series employing different synthesis conditions resulting in two different modes of growth. The first experimental series was performed with a clear homogeneous TPAOH/silica solution crystallizing at 100°C, and the second series with a NaOH-TPABr/silica gel crystallizing at 150°C. Materials produced in the first series showed a smooth and homogeneous surface and a relatively uniform fiber wall with a final thickness of 1.1 μm. In these materials the film was formed by crystals growing outward from the surface of the carbon fiber. Materials produced in the second series were less uniform with a final thickness of the fiber wall of about 3.2 μm. The crystal growth in these materials appeared to take place both in an inward and outward direction starting from the seed crystals adsorbed on the carbon fiber. The hollow fibers prepared were characterized by SEM, XRD, FT i.r., and nitrogen adsorption measurements.
ISSN:0144-2449
1873-3115
DOI:10.1016/S0144-2449(96)00089-9