Reception of Nanostructured Materials Based on Illite for Toxic Substances Immobilization

Background. Using natural clay sorbents on a wide scale, one of the issues that need further development is the issue of used sorbents utilization. From an economic point of view regeneration is inappropriate. Therefore, one of the most suitable methods of waste silica sorbents disposal is their high temperature processing. Objective. Establishing of cobalt ions immobilization in the structure of sorbents based on illite and determination of the optimal heat treatment conditions for the formation of nanostructured materials with improved physicomechanical properties and resistance to leaching. Methods. Refining of illite structural transformation features during heat treatment by NMR spectroscopy and XRD, research of the conditions for obtaining crystallization structures in heat-treated illitic sorbents samples and establishing the relationship between their structure and physicochemical and mechanical properties. Results. The features of illite structural transformations during heat treatment have been investigated, the mechanism of toxic ions (Со2+) fixation in nanostructured matrix has been determined. Physicomechanical (density, open porosity, water absorption, ultimate tensile strength in compression) and physicochemical (resistance to aggressive leaching reagents) properties of illitic waste sorbents treated at different temperatures have been investigated. Conclusions. With increasing the temperature of heat treatment aluminum atoms in the structure of illite are moving from octahedral to tetrahedral coordination, which is accompanied by the formation of three-dimensional nanostructured framework that provides a strong fixation of toxicant ions. It was found that the optimum temperature for heat treatment of illite is 900 °C, which produced nanostructured materials with optimal physicomechanical and physicochemical properties.