The kinetic approach based on the absolute rate theory and the model of a two-site-occupancy adsorption has been proposed to describe the kinetics of sorption of solute at the solid/solution interfaces. The obtained general kinetic equation reduces to the popular empirical formulas (i.e. the Lagergren equation and the pseudo-second order equation) depending on the values of physical and technical parameters which characterize the adsorption system. here, for the case when the adsorption kinetics is governed by the rate of surface reactions. The features of this general equation are shown by presenting some simple model investigations, and its applicability is tested by presenting the analysis of some experimental data reported in literature.