Characterization of the structural and energetic heterogeneity of mesoporous solid surfaces from Q-DTG data

This paper presents the first evaluation of the pore-size distribution and energy distribution of butanol on a silica gel surface on the basis of one experimental run. The Q-TG mass loss and the first derivative Q-DTG mass loss curves of n-butanol thermodesorption from a silica gel sample were made with a Derivatograph Q-1500 D (MOM, Hungary), using an analyser equipped with an automatic ultraslow procedure and a special crucible capable of maintaining the quasi-isothermal heating procedure to increase the resolution of thermal analysis. A numerical procedure was developed for evaluation of the mesopore-size distribution and energy distribution functions of liquids preadsorbed on the mesoporous surfaces from special thermal analysis techniques. This is based on a condensation approximation to treat the kinetics of liquid thermodesorption from solids. A preliminary example is presented of application of the above approach to a quantitative description of the structural and energetic heterogeneities of silica gel surfaces on the basis of a single Q-DTG curve of iz-butanol thermodesorption under quasi-isothermal conditions.