Adsorption from Solutions containing Two Solutes

Abstract

ACCORDING to Gibbs's theory of capillarity, since the surface energy of a solution is at the minimum compatible with the other conditions of equilibrium, a substance which lowers the surface tension will be present at the interface in greater amount than in the bulk of the solution. If two solutes are present, both of which lower the surface tension, it might be expected that that which causes the greatest surface tension lowering will be adsorbed to a relatively greater extent than the other. If the difference is considerable, we may get the almost exclusive adsorption of the more active substance.