Effect of the thermal treatment conditions of granulated active carbons on their properties

Abstract

The results of the thermal modification of AG-OV-1 and SKD-515 activated carbons under varied conditions (by atmospheric oxygen and in an atmosphere of nitrogen) are reported. It was determined that, on the thermal oxidation under selected conditions, the formation of surface oxygen compounds predominated over the process of their destruction. Upon thermal treatment in an inert atmosphere, oxygen-containing acid-type groups were removed from the surface of activated carbons or converted into pyrone (basic) and ether structures. It was shown that a change in the porous structure and the surface functional group composition of the activated carbons depends on not only the conditions of modification but also the properties of the initial carbon adsorbents. Heating in an atmosphere of air led to an increase in the adsorption of both benzene and water vapors, whereas the heat treatment of activated carbons in the inert atmosphere increased the adsorption of only the nonpolar compound (benzene).