Vapor adsorption on coal- and wood-based chemically activated carbons - (II) - adsorption of organic vapors

The present investigation was undertaken to determine the adsorption properties and evaluate the adsorption capacities of several coal- and wood-based chemically activated carbons using the Dubinin-Radushkevich (DR) characteristic adsorption analysis. Limiting micropore volumes (W-0), determined from CCl4 and acetone adsorption isotherms at room temperature, were generally in good agreement with the development of surface area. An effect of adsorbate polarity on the adsorption capacity was found in the case of lower surface area activated carbons rather than higher surface area carbons. This can be attributed to higher density of surface oxygen and carbon surface oxygen functional groups on the lower surface area carbon samples. Characteristic adsorption energy (E-0) values obtained from coal-based KOH activated carbons were generally higher than those obtained from wood-based H3PO4 activated carbons. These results indicate that the coal-based KOH activated carbons have narrower micropores and uniform micropore size distributions. The average micropore sizes were mostly affected by the degree of surface area development which depended on the heat treatment temperature during the synthesis process. (C) 1998 Elsevier Science Ltd. All rights reserved.