This study examines the edge modification of laponite, with a monoalkoxy silane, dimethyl-octylmethoxysilane. The influence of ultrasonics, aging time and silane concentration on the resultant materials is examined. The silylated clays are characterized by XRD, IES, TGA, and Si NMR. The amount of grafted silane was increased by increasing the ratio of silane to clay, sonication of the reaction mixture and ageing the reaction mixture for no more than 24 h to avoid removal of grafted silane due to equilibrium effects.

This study examines the use of laponite, a synthetic smectite, which forms exfoliated silicate layers when dispersed in water, as an inorganic support for titania nanocrystals. Titania nanocrystals are prepared prior to addition to the clay dispersion, by a sol-gel synthesis incorporating a microwave hydrothermal step. The characteristics of the resultant structure such as titania phase, crystallite size and particulate size are examined via X-Ray Diffraction (XRD), Transmission Electron Spectroscopy (TEM) and Infrared Spectroscopy.

A new composite structure with superior photocatalytic activity for phenol decomposition was prepared by reaction between TiOSO 4 and a synthetic layered clay laponite. The high photocatalytic activity resulted from the unique structure of the composite, in which anatase nanocrystals were attached on leached laponite fragments. The new materials are distinctly different from the conventional TiO 2 -pillared clays in structure, which are microporous solids with small TiO 2 particles (a few nanometers in size) as pillars. The large number of the anatase crystals (the active sites) and better accessibility to the sites by UV light and reactant molecules are the major factors enhancing the photocatalytic activity. Important structural properties of the porous composites, such as specific surface area, pore structure, and size of the anatase crystals, were tailored by modulating the Ti/clay ratio and the hydrothermal synthesis temperatures. The performance of the catalysts is related to their structural features, and it is found that the catalytic activity increased with increasing size of the anatase crystals in the catalysts, specific surface area, and mesopore size.

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