SORPTION KINETICS OF AROMATICS IN Y ZEOLITE PELLETS USING THE GRAVIMETRIC METHOD

The sorption kinetics of some aromatics (toluene, p-xylene, o-xylene and p-diethylbenzene) was studied experimentally with a high sensitivity microbalance (± 1µg) at temperatures between 150 and 210oC and concentrations in the adsorbed phase of a maximum of 1 mmol/g. In general, the sorption rates decreased in the following order: toluene > p-xylene > o-xylene > p-diethylbenzene. Two diffusion models were tested against the experimental results. One model considers the mass transfer inside the zeolitic micropores as the controlling diffusion step. The other model supposes that resistance to mass transfer in the macropores (formed during pelletization of the crystals with the amorphous ligand) is the limiting step. The results observed for both models are presented and analyzed