Synthesis and Properties of Titanium Oxide Cross-Linked Montmorillonite

Abstract

Abstract Titanium was introduced into the montmorillonite structure by cation exchange with polymeric Ti cations, formed by partial hydrolysis of TiCl 4 in HCl. On further hydrolysis and heating, TiO 2 pillars in the form of anastase were formed between the montmorillonite layers. The resulting TiO 2 -cross-linked montmorillonites possessed surface areas in the range 200–350 m 2 /g and pore volumes of about 0.2 cm 3 /g and were thermally and hydrothermally stable to 700°C. The basal spacing of products heated at temperatures > 200°C was about 28Å, as determined by X-ray powder diffraction and by N 2 -desorption pore-size analysis. The surface area increased and the pore volume decreased with increasing HCl-concentration in the Ti-solution. The uptake of TiO 2 by the montmorillonite, the surface area, and the pore volume increased with increasing amount of Ti added in the preparation, to about 10 mmoles of Ti/g of montmorillonite. A further increase in the amount of Ti added resulted in a decrease in surface area, but the pore volume and the uptake of TiO 2 remained almost constant. The high porosity and the interlayer spacing of the product are consistent with a structure similar to that previously proposed for smectites, cross-linked with hydroxy-Al oligocations.