ADSORPTION-ISOTHERMS OF WATER ON A SET OF FRACTOSILS AND ON AVICEL PH101R BY FRONTAL ANALYSIS CHROMATOGRAPHY

Residual water adsorbed on the surface of solids can modify significan tly e.g.: stability of solids, properties of colloidal systems, compre ssibility of powders, oxidation phenomena, heterogeneous nucleation in the atmosphere, and may serve as a medium, favourable for the growth of numerous micro-organisms. The aim of this work is the characterizat ion, by physical and thermodynamic parameters, of adsorbed water on th e surface of a set of Fractosils and of Avicel PH 101R . Frontal analy sis chromatography is used for the determination of adsorption isother ms. The analysis of the thermodynamic parameters of adsorbed water ind icates that the water adsorption is either mobile or localized dependi ng on the nature of the solids. The adsorbed, water exists under three states: strongly bonded (up to the monolayer), weakly bonded and free (condensed water).