CHEMICAL ACTIVATION OF THE SURFACE OF THE BURNT ROCK BY VARIOUS MODIFIERS

Abstract

This article presents the results of experimental studies of the process of grafting humic acids and their functional derivatives on modified and unmodified surfaces of burnt rock. It is shown that the inoculation of humic acids on inorganic carriers is more successful with the preliminary activation of the surface of burnt rocks. The acidic and sorption properties of grafted surfaces of humic sorbents with respect to heavy metal ions have been studied. It is shown that many of the modifying additives on the surface of the inorganic carrier can increase these properties by 1.2-2.0 times in comparison with the original rock. Surface modification was carried out by means of impregnation with water solutions of the modifier and subsequent heat treatment; heating at boiling point in water solutions with subsequent heat treatment of precipitation. The interaction of modifiers with the surface occurs by the type of ion exchange for silanol or aluminol groups with weak acidity. It is also possible to connect via hydrogen bonds or dipole-dipole and induction interactions. It was found that the degree of grafting of humic compounds is significantly higher on the activated surfaces of the burnt rock. The content of the modifier on the surface of the carrier is 10-40%, depending on the experimental conditions and the nature of the modifier. The most active modifiers are sodium phosphate and potassium carbonate. The kinetics of the interaction of the surface of the burnt rock with potassium carbonate of different concentrations to reduce the specific electrical conductivity of the reaction mixture over time is studied. A comparative study of the sorption properties of grafted surfaces was carried out, depending on the nature of the functional groups of the humic component of the sorbent, the nature and concentration of the metal ion. The degree of sorption of metal ions with mineral carriers increases from 12-15% to 20-90%, depending on various factors. The highest sorbability of new huminomineral sorbents was noted for lead ions.