SELECTIVE SORPTION OF PHENOL AND RELATED-COMPOUNDS FROM AQUEOUS-SOLUTIONS ONTO GRAPHITIZED CARBON-BLACK - ADSORPTION AND FLOW MICROCALORIMETRIC STUDIES

The adsorption of phenol, cyclohexanol, and n-hexanol from their dilut e binary aqueous solutions onto graphitized carbon black (gcb) was inv estigated at 308.15 K. The adsorption excess isotherms were determined by flow frontal analysis solid/liquid (S/L) chromatography and also b y the classical immersion method. The enthalpies of displacement of wa ter by the C-6-ols were measured by now sorption microcalorimetry. A g eneral thermodynamic treatment was developed for the adsorption at the S/L interface from dilute solutions, with further specifications to m ake the proposed equations operational for the analysis of experimenta l data. A combination of thermal data with adsorption data gave access to the monomolecular adsorption capacities and the molar surface area s of the C-6-ols adsorbed on gcb. The adsorption becomes polymolecular as the consolute phase boundary is approached. The net enthalpies of adsorption, in both monomolecular and multilayer regimes, were determi ned by subtracting a bulk correction term, related to the heats of sol ution at infinite dilution, from the total enthalpies of displacement.