Adsorption, exchange and retention phenomena at the solid-aqueous solutioninterface. 1. Influence of structural, textural and superficial propertiesof 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 un der study. The various conventional techniques for characterizing the textu ral properties (specific surface area and porosity) are first reviewed. The use of a new adsorption volumetric technique in quasi-equilibrium conditio ns is then detailed. Using such a technique, the gas adsorption isotherm ca n be obtained precisely on the whole domain of monolayer filling. The DIS ( Derivative Isotherm Summation) method applied to the experimental results t hen allows a study of the surface energetic heterogeneity, which was diffic ult 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 pr operties of solids and to assign precisely the crystallographic origin of t he Cationic Exchange Capacity (CEC) of kaolinite. It can also be utilized t o understand the retention mechanisms of organic pollutants such as phenol on activated carbons. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.