2003 Volume 29 Issue 5 Pages 653-659
Highly porous activated carbon is used in the removal of volatile organic compounds (VOCs) and
purification of room air. Despite it's wide applications there are relatively few studies on the activated
carbon adsorption of VOCs at trace concentrations of ppb levels.
Adsorption equilibria were measured by the headspace gas chromatography (HSGC) method using
gas chromatography or gas chromatography-mass spectrometer. The reliability of this method was
confirmed by comparing the adsorption isotherms of methanol from the volumetric method. Isotherms
for three types of activated carbon and six VOCs over a wide range of concentrations were determined
and correlated by the Toth and Dubinin-Radushkevich equations, which are generally used for heteroge-
neous adsorbents such as activated carbon. Furthermore an applying this method to binary adsorption
equilibria (dichloromethane + trichloroethylene), the resulrs agreed with values calculated from the
Ideal Adsorbed Solution Theory (IAST).
It was shown that the adsorption equilibria of low concentration VOCs and multi-component
adsorbates could be determined easily and accurately using HSGC method.
