Adsorption of organic solvent vapors on various activated carbons using the chromatorgraphic technique

Abstract

Adsorption of dilute acetone and toluene on various types of commercial activated carbons were mearsured under chromatographic conditions, based on a linear isotherm assumption. Chromatographic pulse responses were analyzed by the method of moment in order to determine adsorption equilibrium constants and adsorption rate constant at the temperature within the range of 50-250 ํC. The selected commercial activated carbons were devided into 3 groups: activated carbons from coconut shell (YAOs), commercial activated carbon (LP814) and carbon molecular sieves (CMSs). At a given temperature, toluene vapor was preferably adsorbed on all types of activated carbons than acetone vapor. The adsorption equilibrium constants depended on the specific surface area and the surface characteristic of the activated carbons. YAOs with high specific surface, result high values of adsorption equilibrium constants. In addition, the hydroxyl on YAO4/8 surface enhanced the adsorbed amount of acetone vapor but reduced the adsorption of toluene. The adsorption on CMSs depended on the average pore diameters and the sizes of the adsorbate molecule. The rate of adsorption for both toluene and acetone were dependent of temperature, corresponding to Arrhenius equation. The heats of adsorption of both vapors were about 3 times heat of condensation, except the heats of adsorption of toluene on YAO4/8 which were less than heat of condensation.