Introduction of aluminum to porous clay heterostructures to modify the adsorption properties

Porous clay heterostrucures (PCHs) are clay mineral based porous materials that have been mainly prepared by intercalation of structures with silica pore walls. In the present work the silica composition of the pore walls was modified by incorporating aluminum oxide, by a co-condensation methodology. Samples were characterized by nitrogen, water and toluene adsorption measurements. For the latter, heats of adsorption were measured using microcalorimetry. Characterization was also made by XRD, FTIR and chemical analysis by ICP and SEM-EDS. The materials were tested towards their selective adsorption properties, using chromatographic separation of toluene/n-heptane and toluene/cyclohexane mixtures. The amounts of aluminum that were introduced in the PCHs by the co-condensation methodology without disrupting the porous structure were limited but, still, they were able to modify the selective adsorption properties of the samples. Above a certain value it produces disruption of the pore structure.