A comparison of the sorption properties of mesoporous molecular sieves MCM-41 and MCM-48

The benzene and triisopropylbenzene sorption capacity and rates of adsorption for several samples of MCM-41 and MCM-48 were compared. The results indicate that for samples with similar pore diameters, MCM-41 has approximately 30% more total capacity for the two hydrocarbons than MCM-48. Pore sizes estimated from the benzene capacity measurements agree well with those calculated from argon adsorption. Estimates made from benzene capacity measurements indicate that for the MCM-41, samples the thickness of the pore walls is approximately 8Angstrom and is independent of pore diameter; the pore wall thickness of the MCM-48 sample is estimated to be slightly larger, approximately 10Angstrom. Sorption rates for all samples were found to be indicative of macropore diffusion limitations rather than mesopore diffusion, hence, no conclusions can be drawn concerning the relative rates of diffusion of benzene through the mesoporous channels characteristic of these samples.