Molecular recognition by Na-loaded alumina pillared clay

Abstract

Varying amounts of Na ions have been loaded to alumina pillared montmorillonite by dispersing it into an NaNO₃ solution, followed by titration with NaOH. The amount of Na ions loaded increased with the pH of the dispersion. As the amount of Na increased, nitrogen adsorption capacity decreased, but the total amount of water adsorption increased. Xylene uptake by the pillared clay decreased in a different manner for the p- and m-isomers as the amount of Na increased, and the uptake ratio of the p- to m-isomers (p/m) had a maximum of ca. 2 for the sample with 0.066 mmol of Na g⁻¹. This finding suggested that the molecular recognition properties of the interlayer micropores of the pillared clay can be finely tuned by controlling the amount of Na ions.