Al-pillared saponites Part 4. Pillaring with a new Al13 oligomer containing organic ligands

Abstract

A saponite from Ballarat (USA) was intercalated with the recently described aluminium polycation [Al₁₃(µ₃-OH)₆(µ₂-OH)₁₂(heidi)₆(H₂O)₆]³⁺. Different Al:heidi ratios during the preparation of the intercalating solutions and Al:clay ratios during the intercalation process were considered. Solids with a basal spacing of 21.8–25.3 Å were obtained in this way, the ordering in their structure depending on the Al:heidi and Al:clay ratios. The surface area of these samples was very low, about 25 g^-1, probably because of the large size of the polycations that fill up the internal galleries of the solids. When calcining the intercalated solids at 500°C, pillared solids with basal spacings of about 16–17.5 Å were obtained, by elimination of the organic part of the polycations. The surface area of the pillared solids increased to values up to 350 g^-1.