Outer-diffusion sorption kinetics in the linear region of the isotherm allowing for complex formation of the sorbate in the initial solution

We have obtained sorption kinetics expressions for the linear metal transfer path in systems consisting of complex forms of the metal (solution phase) and an ion exchanger. When the difference between the characteristic constants of the outer diffusion and of the dissociation stages of the complexes is substantial the extraction of a component by a solvent follows an exponential law irrespective of which of these stages is rate-limiting; if the rate constants are comparable the sorption kinetics are described by a sum of exponentials