ADSORPTION FROM BINARY-LIQUID MIXTURES NEAR THE PHASE-SEPARATION POINT

The paper examines adsorption from a binary mixture of liquids with limited solubility in each other. The behavior of the system is modeled by a free energy functional, which depends on the adsorbate concentration distribution near a plane surface. Adsorption isotherms are calculated, using variational solutions. Their shape significantly depends on the temperature relative to characteristic values, such as the wetting transition point and the critical wetting transition temperatures. The calculated isotherms are compared with their experimental counterparts for the adsorption of benzene on platinum and are found to be in close agreement. The proposed model will be helpful in understanding sorption detoxication in medicine, waste water purification in environmental control, and the segregation of alloy components in materials science.