CHANGES OF ADSORPTION PROPERTIES OF ACTIVE-CARBON BY WET OXIDATION

The surface changes of active carbon by wet oxidation and the resulting changes in adsorptivity were studied. The oxidation of active carbon with hydrogen peroxide or nitric acid solutions caused the changes of the specific surface area from 1101 m2/g to 574 m2/g, immersional heat into water from 9.1 cal/g to 22.9 cal/g and immersional heat into ethanol from 28.4 cal/g to 18.8 cal/g. The average electrostatic field strength increased from 0 to 1.90 x 104 e. s. u./cm2 as well. Pore structure with the diameter around 14 A was partly damaged. The adsorption of water vapor and alizarin yellow and aniline dissolved in ethanol by the carbon was promoted by these oxidations whereas the adsorption of phenol, aniline and alizarin yellow from aqueous solutions were depressed. © 1979 Dr. Dietrich Steinkopff Verlag.