Kinetics of Adsorption on Activated Carbon: II Multisolute Systems

Abstract

Most models that have been developed to describe multicomponent adsorption are based on the assumption that different absorbates interact with regard to equilibrium only. This approach is examined at low adsorbate concentrations. Multicomponent data obtained by the minicolumn method prove that the external mass transfer of one substance is not affected by the simultaneous diffusion of other adsorbates. Bisolute adsorption rate experiments conducted in a batch system show two different impacts of multicomponent adsorption on the intraparticle mass transport. The surface diffusion of the more weakly adsorbed substance can be accelerated when both species are adsorbed simultaneously. On the other hand, surface diffusion of both adsorbates is hindered when displacement processes take place. The experimental results are also used to investigate procedures for lumping individual substances into pseudocomponents with regard to kinetic parameters.