COMPOSITE MATERIALS BASED ON HYDROGEN DIOXIDE WITH CIRCONIA FOR THE DISPOSAL OF ANIONES Cr(VI) AND F(I) FROM WATER SOLUTIONS

Abstract

The review is devoted to the problem of technogenic pollutionof awater environment bytoxic compounds, in particular, anionic compounds Cr(VI) and F(I), as well as technical and scientific ways to solve the problem. The sources of chromium and fluoride compounds entering the environment, their significance for the vital activity of living organisms, including the effect on human health, are considered.The content of chromium and fluorine compounds in various environmental objects was analyzed; special attention was paid to the concentration of these compounds in various water objects (rivers, seas, lakes, groundwater, drinking water, etc.). Fromexistingmethodsfor removing compounds of fluorine and chromium from aqueous solutions а reagent treatment, mutual neutralization, biological, ion exchange and membrane methodsare reviewed. The prospects of methods of electro-membrane technology are considered: electrodialysis, membrane electrolysis, as well as electrodeionization, which combines ion exchange and electrodialysis.The widespread use of these processes is restrained, first of all, by the low chemical and thermal stability of organic polymer membranes and their propensity to accumulate organic impurities. In addition, strongly acidic ion exchangers and membranes that are charge-selective do not exhibit selectivity with respect to certain ions. At the same time, for even better known inorganic membranes, even the charge selectivity is not inherent, which makes it difficult to use them in electromembrane separation processes. Inorganic membranes and granulated ion exchangers on the basis of selective oxide compounds characterized by sufficiently high chemical stability compared with polymeric materials, as well as the selectivity of the absorption of certain ions, are considered as promising for selective electromembrane extraction of anionic compounds Cr(VI) and F(I). It is shown that the perspective direction in the development of modern methods of separation and selective extraction of anions Cr(VI), F(I) is the development of composite selective membranes and ion exchange sorbents that combine the advantages of both a chemically stable inorganic matrix and selective ion exchangers based on the corresponding compounds.