forming a house of cards morphology as described by van Olphen (1979). Lattice fringe images of. PILC8 exhibit a regular pillar distribution over up. 161.
Clay Minerals (1994) 29, 153-167
T H E E F F E C T O F T H E R M A L T R E A T M E N T ON T H E PROPERTIES OF HYDROXY-AL AND HYDROXY-GA PILLARED MONTMORILLONITE AND BEIDELLITE J. T. KLOPROGGE*,
E. BOOY,
J. B. H. JANSEN
AND J . W . G E U S ?
Institute of Earth Sciences, Department of Geochemistry, University of Utrecht, P.O. Box 80.021, 3508 TA Utrecht and ?Department of Inorganic Chemistry, University of Utrecht, P.O. Box 80.083, 3508 TB Utrecht, The Netherlands (Received 8 January 1993; revised 14 June 1993) A B S T R A C T : The
pillaring process of montmorillonite and beidellite with A1 and Ga polymers has been studied using XRD, IR, 27A1,71Ga,and 29SiMAS NMR, TGA, TEM, N2 adsorption and chemical analyses. The A1 adsorption maximum for montmorillonite is close to 5.5 mEq A1/gclay, whereas the maximum for Ga is higher. Basal spacings of both Ga- and Al-pillared clays vary between 16.7 and 18.8 ~,. Freeze-drying of pillared products followed by calcination yielded more regular pillared structures. Pillaring montmorillonite increased the BET surface area from 35 m2/g to 350 m2/g mainly by the creation of micropores
