Configuration of the BET N2 monolayer on a mesoporous silica gel, as obtained from simulation and adsorption calorimetry

J.C.A. DE OLIVEIRA ; R.H. LOPEZ; A.J. RAMIREZ-PASTOR; J. VILLARROEL-ROCHA; K. SAPAG; P. LLEWELLYN; J. ROUQUEROL

Granada

Simposio; 10th International Symposium on the Characterization of Porous Solids (COPS-X); 2014

In a first step, the BET method is expected to provide a characteristic figure for any adsorbent. This is well achieved when nitrogen, the most popular adsorbate for this method, is given, by convention, a cross-sectional area of 0.162 nm2 in the BET monolayer (Sing et al., 1985) and when a few self-consistency criteria are applied in order to select a single region of the adsorption isotherm to carry out the BET calculation (Rouquerol et al., 2007). At this stage, we do not know how closely - or loosely - the resulting BET area is connected with one of the various surface areas which can be defined for a porous solid. Hence the need of a second step to clarify, for any new adsorptive-adsorbent system, the relationship between the BET monolayer content and, for instance, the surface area physically accessible to the adsorptive. We present here a trial to understand this relationship in the case of N2 adsorption on a non-microporous silica gel.