A description is proposed of iodine adsorption on active carbon from solutions in six different organic solvents in terms of general criteria of thermodynamic equilibrium in liquid solutions of limited miscibility of the components. The numerical values of the parameters of the excess adsorption isotherm equation have been determined and the distribution function of the adsorption potential difference of the components, which characterizes the global adsorption heterogeneity of the system, has been calculated under the assumption that the tested mixtures behave like ideal solutions.