dispersed silica, opoka, sorption wastewater treatment, adsorbent utilization, lithification, wastewater, secondary material resource

In modern water treatment technologies, sorption methods play a key role in removing toxic components from wastewater. The most commonly used adsorbent is activated carbon, but its high cost and difficulty of disposal limit its use in water-intensive processes. Natural dispersed silica, such as opoca, provides an efficient and environmentally friendly alternative. The present paper is devoted to the study of a safe method of utilization of spent silica-based adsorbent by lithification method. The results of the analysis of the chemical composition of spent materials, the mechanism of encapsulation of toxic components and their subsequent use as a secondary material resource (SMR) are given. Various additives can be used to improve the effectiveness of opoka as a sorbent or component in waste management processes. These additives improve the sorption, mechanical and chemical properties of the material. International approaches to this task are reviewed. Comparative data with other disposal methods are given.