Pore volume probing of boron-modified MCM-22 zeolite by quartz crystal microbalance assisted study of o- and p-xylene adsorption

A quartz crystal microbalance device (QCM) has been developed and tested in the sorption kinetics of o- and p-xylenes over [Al]MCM-22 and boron-modified [Al,B]MCM-22 zeolites. The results have been compared to those obtained by the GC pulse method. The B-modified MCM-22 material exhibits lower rate and capacity towards adsorption of both isomers which is attributed to a decrease in its pore volume and narrowing of the pore openings as a result of the introduction of boron into the zeolite framework. On the basis of these adsorption measurements suggestions have been made about the impact of the pore topology and the mass-transfer effects on the catalytic behavior of both studied materials. From this point of view the results obtained during transformations of different aromatic hydrocarbons used as test reactants have been discussed.