Applied Catalysis A: General, Vol.183, No.1, 23-33, 1999
Non-aggressive pillaring of clays with zirconium acetate. Comparison with alumina pillared clays
A non-aggressive method of intercalation of smectitic clays with zirconium oligomers from the hydrolysis of a commercial solution of zirconium acetate is presented. Two saponites and a montmorillonite have been selected as the starting materials. The conditions of the intercalation process, pH=3.3 and room temperature, seem to allow a high polymerization degree of the intercalation zirconium species without significantly affecting the layer clay structures. Basal spacings in the 14-24 Angstrom range are obtained for the zirconia pillared clays after thermal treatment at 500 degrees C. Moreover, the specific surface areas and specific micropore volumes of the zirconia pillared clays reached values up to 300 m(2)/g and 0.140 cm(3)/g, respectively. The amounts of ZrO2 fixed varied between 27% and 36% of the weight of the pillared samples. The textural properties of the zirconium intercalated clays were compared with that of their aluminum intercalated counterparts, resulting in higher specific surface areas and micropore volumes for the zirconia pillared saponites calcined at 500 degrees C.
Keywords:CROSS-LINKED SMECTITES;ACID-ACTIVATED CLAYS;SURFACE-AREA;MICROPOROUS ACCESSIBILITY;CATALYTIC PROPERTIES;THERMAL-TREATMENT;MONTMORILLONITE;SOLIDS;AL;HYDROLYSIS