In English

Abstract

The use of hydrophobic silicas as medical adsorbents in comparison with hydroxyl silicas allows to increase the adsorption of some toxins on their surface due to the reduction of water adsorption. The purpose of this study was to find a co-adsorbate that, adsorbed on a hydrophobic surface, would allow the preparation of aqueous suspensions of an enterosorbent based on methylsilica, and, once inside the body, would be easily destroyed by the enzymes of the gastrointestinal tract, freeing its surface for the adsorption of toxins on it. The structure of the hydrate shell and the adsorption capacity of composite materials based on methyl silica and gelatin obtained by different methods were investigated by a set of physical and chemical methods. Low-temperature 1H NMR-spectroscopy has been used to study of water clusters bound to composite surface. It has been found that the water in the composite on the basis of hydrophobic methyl silica and gelatin gel is present in the form of clusters with a radius of 0.5–15 nm and is in a strongly associated state when measured in air. When a liquid hydrophobic medium is added, the water partially passes into a weakly associated state. The bound water reacts to the presence of chloroform by changing the radial distribution of the adsorbed water clusters. It has been shown that for the composite system methyl silica AM-1/gelatin (5/1), the introduction of chloroform into the interfacial space leads to a significant decrease in the interfacial energy, which indicates a partial displacement of water by the hydrophobic solvent at the interface. At the same time, for composites made on the basis of dry powders, this effect is not observed and its interfacial energy has an intermediate value between the interfacial energies of methyl silica and gelatin containing the same amount of water. Adsorption of Congo red as the medium molecular weight toxins marker from aqueous solutions on the studied composites was studied in comparison with methylsilica. It has been found that gelatin in the composition of composites contributes to increasing dye adsorption. The amount of adsorbed Congo red depends on the method of preparation of the composite and the ratio of silica to gelatin. It is concluded that AM-1/gelatin composite systems can serve as effective adsorbents for removing medium molecular weight molecules from aqueous solutions.