Determination off the Hydrophobia Interaction Energy-Application to Separation Processes

Abstract

Surface tension measurement data are described that allow the determination of and the distinction between the long-range Lifshitz-van der Waals (LW) and the short-range (SR) forces that together constitute “hydrophobic interactions”. A novel explicit formulation of the partial contributions of hydrogen bonds to surface tension and to free energy of adhesion is introduced. The different rules that apply to LW and to SR interactions are elaborated upon and the equations needed for the quantitative expression of these two interactions are given. The results obtained by this approach for energies of adhesion are compared with values derived from association and dissociation energies that have been determined earlier, showing an excellent agreement between these two different approaches. A number of applications of our surface-thermodynamic approach (treating LW and SR interactions separately) to various separation processes are discussed with regard to various modes of liquid chromatography, adsorption, membrane processes, blotting, zone melting, partition, precipitation, and other separation methods.