ABSTRACT
Adsorption refers to the accumulation of any species from one of the continuous phases at the
interface between two phases. If the solid-liquid (S=L) interface is in question [i.e., adsorption of a dissolved material (solute) is studied], the wetting of solid material (adsorbent) by the liquid
(medium in which adsorbent is dispersed) and the solubililty of solute in the given liquid (here,
solvent) have to be considered in addition to adsorption. Simultaneous equilibria of adsorption,
wetting, and solubility exist between the components (adsorbent, solvent, and solute). Competi-
tion of solvent and solute molecules for surface sites and also competition of surface and
solvation forces for solute molecules are always present in the S=L adsorption systems. Therefore, a better understanding of adsorption from solutions requires that the interaction of
a solute with a surface be characterized in terms of the fundamental physical and chemical
properties of all the three components (solute, adsorbent, and solvent) of adsorption.
