Kenichi OKUBO

Prediction of Non Ideal Binary Gas Adsorption Equilibria of Volatile Organic Compounds by the Thermodynamic Multicomponent Adsorption Model.
Shoichi FUJITA , Toshiya KOMATSU , Shuji HIMENO


The ideal adsorbed solution theory (IAST) is used widely to predict the multicomponent adsorption equilibria, but it has a serious problem with poor predicting caused by non-ideality of the adsorbed phase. So, the purpose in this paper is making it possible to predict non-ideal binary adsorption on activated carbon BPL by using non ideal adsorbed solution theory(NIAST) proposed by Siperstein and Myers. Pure isotherms for methanol, acetone, benzene, n-hexane, toluene were measured at three temperatures(293, 323, 353 K) over the pressure range of relative pressure 2�~10-7�|1�~10-2 on BPL. Toluene/benzene, benzene/acetone, n-hexane/acetone, benzene/methanol for mixed gas adsorption equilibria were measured by HSGC and dynamic method. The Toth and the Dubinin-Radushkevich equation were correlated with single gas adsorption isotherm in all ranege of pressure, temperature and all kinds of VOCs with good accuracy. The isosteric heats of adsorption were calculated with the Clausius-Clapeyron equation. The isosteric heats of adsorption for these VOCs were decrease with adsorbate loading.Non-ideal behavior of mixed gas adsorption (benzene/acetone, n-hexane/acetone) was good correlated with NIAST, while it was difficult to predict these binary systems by IAST.
We concluded that NIAST could predict the non-ideal binary gas adsorption equilibria of VOCs.