Study of adsorption equilibria in the systems ternary liquid mixtures-modified activated carbons

The adsorption abilities of commercial activated carbon after thermal and c hemical treatment were investigated. The chemical character of carbon surfa ces was determined by applying the thermogravimetric method, measurement of adsorption isotherms of water vapor, and the process of neutralization of surface functional groups. Total amounts of oxygen and nitrogen in all carb on samples were estimated by elemental analysis. Adsorption-desorption isot herms of benzene vapor were used to determine the parameters of the Dubinin -Radushkevich equation characterizing the porous structure of investigated carbons. These analyses show that chemical modification of carbon samples l eads to strong differentiation of the chemical character of adsorbent surfa ces; however, the porous structures show distinct similarity. In order to s tudy the adsorption equilibria from liquid phase, the adsorption isotherms were measured for ternary mixtures of benzene, diethyl ketone, and n-heptan e on all carbons. A strong effect of the chemical character of the carbon s urface on liquid adsorption was found and discussed for all systems. (C) 19 99 Academic Press.