Main factors controlling the texture of zirconia and alumina pillared clays

The texture development has been studied of a saponite and a montmorillonite, intercalated with zirconium and aluminum oligomers, after calcination at 773 K. Remarkable differences were observed among the samples, depending on the source of the intercalating polycations and the parent material. On calcining, the alumina pillared clays suffered noticeable specific surface area and micropore volume losses, which were related to the pillar density of the samples. On the contrary, the zirconia pillared clays showed a slight surface area increase, which affected both the micropores and the mesopores and could be due to the combined effect of the thermal decomposition of the zirconium oligomers and the possible presence of mesoporous ZrO2 particles. Horvath-Kawazoe and Cheng-Yang methods were both applied in order to obtain the micropore size distributions of the solids. (C) 2000 Elsevier Science B.V. All rights reserved.