Preparation and Adsorption Properties of Mesoporous Pillared Clays with Silica Sol

New mesoporous silica-pillared montmorillonites were prepared by the post-intercalation of bulky organic cations into silica sol exchanged montmorillonites. Pillared clays with SiO2-Fe2O3 sol were first prepared, followed by the dissolution of iron oxide (or hydroxide) from the pillars with hydrochloric acid. A portion of the interlayered sol particles were then replaced with organic cations which led to a rearrangement of silica sol particles between the silicate layers. The removal of the organics by burning resulted in mesoporous sol pillared clays with an average pore size of more than 20 Å in diameter. The BET specific surface area increased to as high as 950 m2/g in these mesoporous pillared clays.