Silica from sepiolite: Preparation, textural properties, and use as support to catalysts

Silicas with high surface areas have been obtained by acid leaching of sepiolite. The influence of the preparation conditions (acid type and concentration, solid concentration, temperature and time) on the silica properties has been studied with the aim of producing silicas which may have potential uses as catalyst supports. The silicas have been characterized by chemical analysis, XRD, SEM, Si-29 MAS NMR, TGA. It is shown in this study that the silicas obtained by acid leaching of sepiolite develop high surface areas (500 m(2) g(-1)) with a high contribution of mesoporous surface (approximate to 90%). The textural characteristics after calcination at temperatures above 500 degrees C are stable, even after long aging times (>6 months). Preliminary benzene hydrogenation tests have been performed over Ni-impregnated silicas and compared with equivalent catalysts prepared with commercial silicas.