Adsorption, exchange and retention phenomena at the solid-aqueous solution interface.: 1.: Influence of structural, textural and superficial properties of solids

A crucial step, leading to a proper understanding of adsorption mechanisms at the solid-aqueous solution interface, lies in the precise determination of the structural, textural and energetic properties of the solid phases under study. The various conventional techniques for characterizing the textural properties (specific surface area and porosity) are first reviewed. The use of a new adsorption volumetric technique in quasi-equilibrium conditions is then detailed. Using such a technique, the gas adsorption isotherm can be obtained precisely on the whole domain of monolayer filling. The DIS (Derivative Isotherm Summation) method applied to the experimental results then allows a study of the surface energetic heterogeneity, which was difficult to assess using conventional techniques. Two examples are then used to illustrate the potentialities of the technique. Through a judicious choice of the adsorbate, such analysis can be used to characterize the exchange properties of solids and to assign precisely the crystallographic origin of the Cationic Exchange Capacity (CEC) of kaolinite. It can also be utilized to understand the retention mechanisms of organic pollutants such as phenol on activated carbons. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.