Nanocomposite systems pectin/silica and their properties

Composite systems based on pectins and silica materials are investigated in the paper. This can be a promising direction in the creation of systems with high adsorption characteristics in relation to molecules of medium and large molecular weight. In particular, the prospects of creating composites based on a mixture of hydrophobic and/or hydrophilic silicas (AM-1 and/or A-300, respectively) with pectin are shown. It has been found that the maximum adsorption of methylene blue occurs from the model solution at pH 5.5 on the surface of all the studied samples. The A-300/AM-1/pectin composite system proved to be the best, regardless of the amount of pectin in the composite (5 or 10%) at different pH values (1.5 and 5.5), compared to other adsorbents. The purpose of this work was the construction of composite systems based on pectin and silicas (hydrophobic and hydrophilic and their mixtures), the study on their adsorption parameters in relation to the cationic dye methylene blue, and the effect of pectin on the hydration characteristics of silica sorbents. The peculiarities of the formation of water layers in hydrated nanocomposite systems were investigated by the method of low-temperature 1H NMR spectroscopy. It has been shown that by changing the concentration ratio of pectin and hydrophobic silica, the structure of the interfacial water and the energy of water interaction with the surface can be controlled. Due to this, new types of functionalized materials can be created for use in medical composites. It has been shown that composite systems containing AM-1 hydrophobic silica are characterized by a decrease in interfacial energy in a weakly polar environment, which is due to the thickening of interfacial water clusters, and the size of surface water clusters decreases during the process of defrosting the system. It has been found that the amount and binding energy of water in heterogeneous systems based on pectin are influenced by the processes of interparticle interactions between heterogeneous components, which likely determine the degree of association of molecules in the water layer.