Assessment of Connectivity in Mixed Meso/Macroporous Solids Using Nitrogen Sorption
Nitrogen sorption isotherms of porous solids often exhibit hysteresis between adsorption and desorption. Application of percolation theory to this hysteresis enables the connectivity of the pore network to be assessed. However a major limitation is that for mixed meso/macroporous materials not all of the pores are filled with condensed nitrogen at the maximum relative pressure reached in a conventional adsorption experiment. A modified nitrogen sorption experiment is described in which the sample is immersed in liquid nitrogen before the desorption branch of the isotherm is determined. This allows the true shape of the hysteresis loop to be obtained.
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