Sorption Isotherms and Kinetics

Abstract

The distribution of metal ions between the biosorbent and the metal solution, when the system is at equilibrium, is of paramount importance in determining the maximum adsorption capacity of the biosorbent toward the metal ions. The adsorption data are to be analyzed in the light of various isotherm models like Freundlich and Langmuir adsorption models. The Freundlich isotherm model proposes a monolayer sorption with a heterogeneous energetic distribution of active sites, accompanied by interactions between adsorbed molecules. The Langmuir isotherm model suggests that uptake occurs on a homogenous surface by monolayer sorption. In addition, the model assumes uniform energies of adsorption onto the surface and no transmigration of the adsorbate.