Miho YAMANA

Determination of Single and Binary Gas Adsorption Equilibria of

Volatile Organic Compounds in trace concentration using

Headspace Gas Chromatography Method

Toshiya Komatu, Shoichi Fujita and Shuji Himeno


In recent years, various Volatile Organic Compounds(VOCs), such as benzene which are emitted from automobile exhaust and industrial processes exist in the atmosphere in trace concentration. VOCs are feared of an influence on human being health because of being exposed to it for a long time in trace concentration. So, adsorption using highly porous activated carbon is one of method to remove it. It's wide applications, but there are relatively few studies on the activated carbon adsorption of VOCs at trace concentration of ppb levels and mixed-gas, so in this study we proposed a method to determine it and understood adsorptive properties.
In this study we used the Headspace Gas Chromatography(HS-GC) method. Adsorption isotherms for 2 different types of activated carbon and 8 types of VOCs over a wide range of concentrations were determined and correlated by the Toth and Dubinin-Radushukevichi equation, which were generally used. As the results, using HS-GC Method enabled to determine in trace concentration and it is clear that the adsorption capacity was less than 1% in ppb levels.
Furthermore in using this method the results from two systems of binary adsorption equilibria(dichloromethane+trichloroethlen),(benzene+toluene) were in correlation with that of the Ideal Adsorbed Solution Theory(IAST) which were generally used, but the results from a system of (benzene+ Acetone) were not, so acetone could not be regarded as ideal solution in adsorbed phases.

It is shown that the adsorption equilibria in trace concentration VOCs and multiple components adsorbates could be determined easily using HS-GC method.