Characterization of silicas by inverse gas chromatography at finite concentration: Determination of the adsorption energy distribution function

Abstract

Amorphous and crystalline silicas, eventually modified by heat treatment or by surface grafting of alkyl chains, were investigated by inverse gas chromatography, a method which easily provides adsorption isotherms of various linear alkanes. The isotherms were analyzed in order to obtain the adsorption energy distribution of alkane probes. The distributions were calculated using a local solution of the adsorption integral equation which is evaluated and discussed. Silicas show typical energy distribution patterns. Furthermore, the grafting of hexadecanol chains on the silica surface brings the greatest changes in the energy distributions.