Liquid-phase adsorption experiments on ordered mesoporous silicas

SBA-15, SBA-16 and MCM-48 silicas with hexagonal p (6) over bar mm, cubic Im (3) over barm and cubic Ia (3) over bard mesopore structure were synthesized according to known methods reported in literature and characterized by X-ray diffraction and nitrogen adsorption. Liquid-phase adsorption experiments were performed on all three materials. The adsorption behavior of binary liquid model mixtures was studied over the whole concentration range with regard to the separation quality of the solid and the dependence on the chain length of adsorptive molecules. Inverted U-shape isotherms were found indicating that the silicas are highly selective for polar components. So far, an influence of mesopore size or structure on liquid excess isotherms cannot be extracted from the measured data. The present work is a first step to create a data base of liquid-phase adsorption on solids with ordered mesopore structure.