Nitrogen adsorption on porous silica : model-dependent analysis

The full nitrogen isotherm of a porous silica (silica gel 60) is studied and is compared with recent theoretical predictions based on extensions of the Frenkel-Halsey-Hill approach to adsorption on fractal surfaces. The analysis is shown to be model dependent and contrary to previous claims the isotherm does not provide any clear-cut information on the morphological features of the surface