DISPLACEMENT PROCESS ON HYDROPHILIC HYDROPHOBIC SURFACES IN METHANOL-WATER MIXTURES

The adsorption from methanol/water and the enthalpy of displacement of methanol by water were studied on K-60 silica gel, on graphitized PRINTEX-80, and on n-alkylammonium vermiculites. The adsorption between the hydrophobized silicate layers was followed by x-ray measurements. The excess isotherms of alkylammonium vermiculites in methanol/water exhibit two maxima corresponding to the two steps of the individual isotherm. The equilibrium constant of the exchange of water by methanol is calculated. For calculating the adsorption capacities and molar adsorption potentials, a new equation is proposed which combines the adsorption excess quantities with free energy and enthalpy functions.