Adsorption reaction and diffusion based-models with solid-phase concentration-dependent coefficient for adsorption of reactive dye

Abstract

ABSTRACTThe adsorption behavior for tartrazine removal was studied in batch and fixed-bed column operations with the commercially available anion exchange resin. The breakthrough curves were simulated according to mathematical models that considered the mass transfer resistance, such as the film diffusion, pore diffusion, and a combination of both. Analyses of adsorption reaction models in a batch experiment could be an efficient way to select an adsorption model in a fixed-bed operation, because in this study, such models represented the film and pore diffusion phenomena in a separate initial concentration range. The simulation analysis showed that the adsorption process could be controlled by a combination of film and internal particle resistance, and the tartrazine adsorption process was strongly affected by the internal mass transfer resistance. The concentration-dependent rate expression was used to improve the prediction accuracy of both the film and pore diffusion models, and its application to conventional mathematical models could not define meaningful segments in the adsorption process, but could provide a most useful and accurate way of quantitatively estimating the mass transfer effect.