Equilibrium and heat of adsorption for organic vapors and activated carbons.

Determination of the adsorption properties of novel activated carbons is important to develop new air quality control technologies that can solve air quality problems in a more environmentally sustainable manner. Equilibrium adsorption capacities and heats of adsorption are important parameters for process analysis and design. Experimental adsorption isotherms were thus obtained for relevant organic vapors with activated carbon fiber cloth (ACFC) and coal-derived activated carbon adsorbents (CDAC). The Dubinin-Astakhov (DA) equation was used to describe the adsorption isotherms. The DA parameters were analytically and experimentally shown to be temperature independent. The resulting DA equations were used with the Clausius-Clapeyron equation to analytically determine the isosteric heat of adsorption (deltaHS) of the adsorbate-adsorbent systems studied here. ACFC showed higher adsorption capacities for organic vapors than CDAC. DeltaHS values for the adsorbates were independent of the temperature for the conditions evaluated. DeltaHS values for acetone and benzene obtained in this study are comparable with values reported in the literature. This is the first time that deltaHS values for organic vapors and these adsorbents are evaluated with an expression based on the Polanyi adsorption potential and the Clausius-Clapeyron equation.