Properties of dispersed systems are essentially determined by the values of the specific surface area and by the pore structure parameters characteristic of the layered solid powders. The problem has been studied for years. Today it becomes important due to the rapid development of the material science and new technologies. As evidence for it serve the increasing number of articles, reviews and monographs, as well as the holding of national and international symposiums, the most important ones among them being the series COPS (Characterisation of Porous Solids) organised by IUPAC. A lot of experimental methods are used to study the porous structure of solids. It is well known that the determination of adsorption and desorption isotherms is the most important and frequently used method. The Commission on Colloid and Surface Chemistry Including Catalysis of International Union of Pure and Applied Chemistry (IUPAC) has elaborated recommendations for reporting the sorption data with special reference to determination of the surface area and of porosity. The recommendations reflect the recent development of adsorption theory and the progress in studies of porous solids structure. The methodology of the present work was based on these recommendations. The main idea of this research was to resolve certain problems of theory and practical application of highly dispersed systems with layered solid powders. The pore structure characteristics, the specific surface area, and their changes were studied. The studied materials are of great importance for Latvian economics. Ferric hydroxides, oxides and clays are widely found in Latvia as important components of soil where they participate in ion - exchange -adsorption processes. These compounds are significant also in other natural colloidal systems and mixtures. The surface of clay particles is frequently covered with hydroxicompounds of iron. Research of sorption capacity of these materials is an urgent problem for Latvia 4 especially now. It is connected with environmental protection problem and its improvement. In fact, mathematicians have worked on models on assessment of risks caused by outflow of oil (U. Buikis, 1989). The absence of sorption data for Latvian minerals (clays included) makes it difficult to fit the models to the actual situations. The soil remediation in former Soviet army missile bases is also an urgent problem. The knowledge on the surface phenomena occurring in the nature needs elucidation. It is important to investigate the possibilities of introducing the Latvia’s clays into new, non- traditional areas of applications, such as sorbents or flocculates of water treatment, as bleaching material of vegetal or other oils, etc.