Preparation and Properties of Clays Pillared with SiO2–TiO2 Sol Particles

The silicate layers of montmorillonite clay were pillared with SiO2–TiO2 sol particles. Although only the SiO2 sols were negatively charged, the SiO2–TiO2 mixed oxide sols were positively charged and could be ion-exchanged with the interlayer cations of montmorillonite. The resulting pillared clays had a basal spacing expanded to more than 40 A; the spacing was maintained during calcination up to 773 K. The adsorption properties of the calcined samples were studied for nitrogen as well as organic vapors. A structural model for the arrangement of the intercalated sol particles is proposed in which small SiO2–TiO2 sol particles are packed between the silicate layers. Micropores with a slit width of 10–12 A are formed in the interstices between the sol particles and the silicate layers.