MCM-41 - A MODEL SYSTEM FOR ADSORPTION STUDIES ON MESOPOROUS MATERIALS

Purely siliceous MCM-41 materials with different pore sizes were synthesised. The obtained nitrogen isotherms of these materials varied from a ''type I-like'' isotherm (small pore size) over a reversible type IV isotherm (intermediate pore size) to a typical type IV isotherm, which shows pore condensation with hysteresis. Similar types of transition states and hysteresis curves are observed by H-1 nuclear magnetic resonance (NMR) by monitoring the proton signal intensity of the mobile water molecules confined in the pores versus temperature. The consistency observed between the two methods makes H-1 NMR a valuable additional technique for characterisation of mesoporous materials.