ADSORPTION OF BINARY-MIXTURES OF HEPTANE AND ALKANOLS BY ACTIVATED CARBON

The adsorption isotherm of heptane-hexanol on activated carbon at 298 K is presented and compared with our earlier work on heptane-ethanol a nd heptane-butanol mixtures under similar conditions. The data show th at the preferred adsorption shifts from the alkane to the alkanol as t he 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 appr oximate theoretical model (surface phase model). These results show th at the minimum thickness of the layers required to achieve thermodynam ic consistency between the surface phase model and the experimental da ta increases as the length of the alkanol chain decreases. All the sys tems exhibit smaller deviations from ideality in the adsorbed phases t han in the bulk.