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A new approach is proposed for creating modified materials entailing the selection of matrix-modifier pairs, in which the structural characteristics of the components, namely, the distance between the ion-exchange sites on the matrix surface and distance between the active groups in the modifier, are similar. A procedure was developed for the modification of layered silicates with rigid structure using polyhexamethylene guanidine without a greater-than-equivalent amount of modifier. It is shown that modifier is held firmly by inorganic matrix.

A qualitative and quantitative description is given for the H3 hysteresis loop at low pressures using the generalized Dubinin–Astakhov equation. Irreversibility of the adsorption system was taken into account by introducing an additional governing parameter. A relationship was found between this parameter and the potential barrier for desorption from adsorption traps. The proposed equation satisfactorily describes the hysteresis loop at low pressures for a series of systems.

A complex approach based on treatment of calorimetric data using the Guggenheim–Andersen–de Boer and modified Jovanovic equations was developed to evaluate the energetic and structural heterogeneity of microporous and mixed micro/mesoporous zeolite adsorbents. The calculated dependence of the hexane adsorption energy distribution function for the Y-US-Ex micro/mesoporous zeolite on the adsorbate pressure is in good accord with the calorimetric curves for the differential heats of adsorption, which indicates the suitability of this theoretical approach.

It was shown, by ab initio calculations of the characteristics of hydrophilic centers formed on the surfaces of organosubstituted kaolinites with equivalent and superequivalent modifications, that superequivalent modifications of the mineral surface with octadecylammonium chloride, i.e. blocking the hydrophilic centers of the ionic-adsorbed cationic surface-active substance with the molecular adsorbed amine, led to the redistribution of the electron density close to these centers, in particular to the decrease in the effective charge at the hydrophilic centers. The calculated structures and energetics of nanostructures formed by the adsorption of water molecules at such hydrophilic centers showed that such redistribution decreases the energy of their interaction with water, which resulted from theoretical decrease in the energetic effects of hydration of the centers effectively agreed with the experimental values of the heats of adsorption. It was shown that for such adsorbtion systems the energetics were suitable for the formation in the region of the adsorption centers of cyclic structures of water.

The molecular statistical method for evaluating the distribution of active sites of various adsorbents relative to their energies has been improved. This method is used not only for the treatment of experimental data on the adsorption of hydrocarbons on various adsorbents, which is the usual procedure, but also data on the adsorption of polar water and methanol molecules on the active sites of adsorbent surfaces. Two types of active sites differing in energy have been shown to exist on the surface of graphitized carbon black, the complex shungite carbon/mineral adsorbent, and modified Silochrom. Chromatographic, calorimetric, and structural adsorption data were used to establish the relationship between the observed maxima of the energy distribution function of the adsorption sites with concrete adsorption sites or pores of the surface, on which the molecules are adsorbed.

A complex theoretical-experimental investigation has been carried out on the interaction of water with hydrophilic centers-phenolic and carboxyl groups-on the surface of graphite and graphitized thermal carbon black in low surface occupation range. It is shown that microclusters, formed by the absorption on such centers, have a cyclic structure of 4–5 molecules similar to those observed in liquid water and on the surface of silver iodide. The formation of such structures is shown to be energetically advantageous. It is shown that the generalized Langmuir equation, derived from molecular-statistical considerations, is considerably better over a wide range of relative pressure for the description of the experimental isotherm for the adsorption of water on graphitized thermal carbon black and allows for a better interpretation of structural and energetic characteristics of adsorbed systems obtained by a complex of methods.

An adsorption isotherm that generalizes the Langmuir equation for the cluster adsorption of several interacting molecules at one center is proposed. In the case of the adsorption of water molecules at surface hydroxyl groups on modified silica it was shown that the energy and structure characteristics of such a system, determined by the ab initio method, agree with the experimental data and lead to satisfactory agreement with the parameters of the proposed isotherm.

The hydration of Ca2+ and Mg2+ exchange cations in solution and in 10- and 8-membered silicon—oxygen rings of the clinoptilolite was studied by ab initio and MNDO quantum-chemical methods. The coordination numbers of these cations with respect to water molecules and their hydration energies were determined. It is shown that the localization of Ca2+ and Mg2+ in the clinoptilolite structure was different for the dehydrated state and the partially hydrated state. The ion exchange sorption energy calculated for the Ca2+—Mg-Cli system was in satisfactory agreement with the experimental data.

Values and heats of benzene adsorption on modified kaolinite and silica samples are measured by adsorption calorimetry. Entropy diagrams are calculated for benzene adsorbed on these samples. Obtained results are compared to entropy losses theoretically calculated for benzene molecules using the models of ideal localized and nonlocalized adsorption. It is demonstrated that, depending on the type of an inorganic matrix, the nature of a modifier, and the degree of modification, the adsorption of benzene molecules on studied sorbents is described by the models of a supermobile nonlocalized adsorption or a nonlocalized adsorption accompanied by the loss of some rotational degrees of freedom. For a rare case of the supermobile adsorption of benzene on the modified silica, the vibration frequency of its molecules with respect to the surface is calculated.

Through quantum-chemical modeling (MNDO method), a realistic description has been obtained for the structure of a section of the basal surface in a dioctahedral layer silicate without any isomorphous substitution, namely (SiO2H)6[Al(OH2)2OH]2OH, and with isomorphous substitutions Al → Si in the tetrahedral network and Mg → Al in the octahedral network, with compensation of unit negative charge by an Li+ cation that may be either anhydrous or hydrated with one to four water molecules. The positioning of a small trigonal cation in a ditrigonal hole on the surface of an anhydrous or partly dehydrated layer silicate is shown to be a property of a structure with nonstoichiometric isomorphism in the octahedral network rather than in the tetrahedral network. A study has been made of the interrelation between the positions of the exchange cation in the hole and the proton of the hydroxyl group forming the bottom of the hole. Values calculated for the enthalpy of hydration of the Li+ cation by three successive molecules of water are in satisfactory agreement with the experimental values.

A study has been made of the applicability of the semiempirical MNDO method to the description of energy characteristics and structural features of the structural elements in layered silicates containing Li+ exchange ions in various degrees of hydration. It has been shown that this method can give a realistic description of the characteristics of structure and energy of complexes formed on the basal surface of a layered silicate — kaolicate — upon hydration of an Li+ exchange ion situated in a hexagonal hollow.