Capillary transport in adsorption from liquid phase on activated carbon

Two models presented here predict the kinetics of adsorption from solution. The adsorbate is considered to form a capillary separated phase inside the micropores. The transport in the adsorbed phase is modeled as capillary tr ansport under the influences of gradients in capillary pressure. In model I the capillary separated phase is assumed to be continuous, while in model II it is assumed to be discontinuous. The effective adsorbed phase diffusio n coefficient for this transport is directly related to the pore-size distr ibution, which can be found from the sorption isotherm. In both models the overall apparent diffusion coefficients are compared with experimental data . Both models satisfactorily predict the dependency of the diffusion coeffi cient on carbon loading. Model I slightly underestimates the temperature de pendency of the effective diffusion coefficient, while model II gives a goo d prediction of the influence of temperature on the rate of adsorption.