Experimental verification of the model of adsorption in biporous particles

The model of adsorption in bidisperse pellets was used to predict experimental breakthrough curves for SO2 adsorption in natural clinoptilolite in three different scale columns—0.3 cm GC, 1.8 cm laboratory and 20 cm ID column. The model accounts for nonlinear equilibrium on the microparticle surface, macropore diffusion, microparticles size distribution and concentration dependent micropores diffusivity. Kinetic and equilibrium parameters were obtained under dynamic conditions and used in the model together with data on the microparticles size distribution. External mass transfer in the film around the particles and axial dispersion in the bed were taken into account. Better agreement between experiment and theory was obtained for larger pellets where macropore diffusion control was of greater importance. When microparticles become rate-limiting the correspondence with the model predictions is less satisfactory, the calculated curves being broader than the experimental ones. A number of numerical experiments were performed and the results were analysed in relation to the structure of the model and the correspondence between experimental data and model parameters.