Low temperature constant rate thermodesorption as a tool to characterise porous solids

An apparatus is described allowing the study of controlled rate thermodesor ption (CRTD) in the temperature range from 163 to 473 K and in the residual pressure region around 10(-3) mbar. This apparatus is designed with the ai m to increase the sensitivity in the estimation of the specific surface are a with respect to traditional adsorption experiments. The thermodesorption of water from a model mesoporous MCM-41 sample is studied using this appara tus. The thermodesorption curve obtained is related to the mesopore size di stribution via an expression based on the Kelvin law. These results compare well with those obtained by adsorption gravimetry of water at 303 K on the same MCM-41 sample. (C) 2000 Elsevier Science B.V. All rights reserved.