PREDICTION OF HYSTERESIS DISAPPEARANCE IN THE ADSORPTION-ISOTHERM OF N-2 ON REGULAR MESOPOROUS SILICA

The thermodynamic Saam-Cole approach including the molecule-surface in teraction was applied to explain the critical pore width at which the adsorption hysteresis of Nz on regular mesoporous silica disappears. T he difference of the critical thickness of physisorbed layers on the p ore wall upon condensation and evaporation was associated with the por e wall roughness inherent to the atomic structures, showing that the c ritical pore width for the disappearance of the adsorption hysteresis is in the range of 3.6 to 3.8 nm.