Adsorption of binary mixtures of heptane and alkanols by activated carbon

Abstract

The adsorption isotherm of heptane–hexanol on activated carbon at 298 K is presented and compared with our earlier work on heptane–ethanol and heptane–butanol mixtures under similar conditions. The data show that the preferred adsorption shifts from the alkane to the alkanol as the length of the alkanol chain, relative to that of the alkane chain, increases. The surface mole fraction, interfacial tension differences and surface activity coefficients have been estimated based on an approximate theoretical model (surface phase model). These results show that the minimum thickness of the layers required to achieve thermodynamic consistency between the surface phase model and the experimental data increases as the length of the alkanol chain decreases. All the systems exhibit smaller deviations from ideality in the adsorbed phases than in the bulk.