A model for selective adsorption with a localized adsorption energy

A model for the selective adsorption phenomenon in an isotropic liquid considering a localized adsorption energy is proposed. The fundamental equations governing the adsorption phenomena are established, by considering the mass balance equation in a limited region close to the interface. The electric field distribution inside the sample and the behavior of the chemical potential are determined as a function of the initial concentration of the fluid phase. This model allows us to obtain isotherms that lie outside the Langmuir approximation, because the effective potentials relevant to the adsorption process are determined in a self-consistent manner.