Abstract

CHE-GALICIA, G.; MARTINEZ-VERA, C.; RUIZ-MARTINEZ, R.S.  and  CASTILLO-ARAIZA, C.O.. Modelling of a fixed bed adsorber based on an isotherm model or an apparent kinetic model. Rev. Mex. Ing. Quím [online]. 2014, vol.13, n.2, pp.539-553. ISSN 1665-2738.

Isotherm model and apparent kinetic model are simple approaches, which are indistinctly used to predict the kinetic behaviour of the adsorption phenomena. The main objective in this work was to elucidate when these approaches should be coupled to a pseudo-heterogeneous fixed-bed adsorber model to describe reliable breakthrough curves when experimental data at industrial scale are not available. To achieve this, an adsorption column packed with a low-cost natural zeolite was modelled for the removal of Rhodamine B (RhB). To have certainty in the model predictions, equilibrium and kinetic experiments were carried out. Freundlich isotherm model and a pseudo second order apparent kinetic model accounting for diffusion phenomena led to the most adequate fit to experimental data. Experimental and simulations results indicated that the use of an isotherm model (LDF-M) or an apparent kinetic model (AkA-M) in the packed bed adsorbed model predicted similar tendencies regarding the effect on the breakthrough point of the different parameters considered. Nevertheless, the shapes of the breakthrough curves predicted by both models were significantly different, suggesting that an apparent kinetic model is necessary to have reliable prediction of the industrial behaviour of this studied zeolite since intraparticle mass transport resistances are significant.

Keywords : packed bed adsorber; breakthrough curves; adsorption kinetics; isotherm model; apparent kinetic model.