Preparation and Characterization of Bidimensional Zeolitic Structures Obtained from Synthetic Beidellite and Hydroxy-Aluminum Solutions

A. Schutz, W. E. E. Stone1, G. Poncelet and J. J. Fripiat2
Groupe de Physico-Chimie Minérale et de Catalyse, Université Catholique de Louvain Place Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium
1 Section de Physico-Chimie Minérale (MRAC), Place Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium.
2 University of Wisconsin-Milwaukee, Department of Chemistry, Milwaukee, Wisconsin 53201.

Abstract: Beidellite was synthesized hydrothermally from a noncrystalline gel at 320°C and 130 bar pressure. The beidellitic character of the product was verified by infrared spectroscopy on the NH4+-exchanged form. Intercalation was achieved with hydroxy-aluminum solutions having different OH/Al molar ratios. The solutions were investigated by several methods, including 27Al nuclear magnetic resonance. Essentially, two Al species were detected: monomeric Al and a polymerized form containing Al in four-fold coordination. This latter species was found to be selectively fixed in the interlamellar region, which resulted in a stable spacing of 18 Å at 110°C and 16.2 Å at 700°C. The pillared beidellites had specific surface areas of >300 m2/g, mainly due to micropores. Both Brönsted and Lewis acid sites were evidenced by infrared spectroscopy using pyridine as a probe molecule.

Key Words: Acid sites • Beidellite • Hydroxy-Al • Infrared spectroscopy • Nuclear magnetic resonance • Pillaring • Synthesis

Clays and Clay Minerals; August 1987 v. 35; no. 4; p. 251-261; DOI: 10.1346/CCMN.1987.0350402
© 1987, The Clay Minerals Society
Clay Minerals Society (www.clays.org)