Preparation and characterization of pillared magadiite
Journal
Chemistry of Materials
Journal Volume
5
Journal Issue
6
Pages
770-777
Date Issued
1993
Author(s)
Wong, S.-T.
Abstract
Aluminum Keggin ion-pillared magadiite was synthesized from Na-magadiite, Na2-Si14O29·11H2O, by ion-exchange with Keggin ion solution. The precursor for this pillaring reaction is n-hexylamine-intercalated magadiite, whereby the free interlayer spacing of H-magadiite was greatly expanded by n-hexylammonium ions and free amines. The presence of Keggin ion pillars in the interlayers of the product was confirmed by 27Al and 29Si MAS-NMR studies. XRD analysis showed that the resultant pillared product is highly disordered, but N2 adsorption-desorption analysis showed that the pillared magadiite contains both micro- and mesopores. The presence of pillars in the interlayers of magadiite was further confirmed by the higher thermal stability and surface area over Na-magadiite, as well as the possession of microporous structures. 2-Propanol dehydration studies on the acid-base properties of Keggin ion-pillared magadiite revealed that it consists mainly of acidic sites. These sites are the Si-OH groups of the silicate layers and the Al-OH groups of the Keggin ions. The latter was found to be stronger acid sites. © 1993, American Chemical Society. All rights reserved.
Type
journal article