Modeling of Adsorptive Filtration of a Leather Dye in a Fixed Bed Column

Abstract

Activated carbons offer an efficient option for the removal of organic and inorganic contaminants from water. However, due to its high costs and difficulty in the regeneration, other low cost adsorbents have been used. In this work, the adsorption capacity of an adsorbent carbon with high iron oxides concentration was compared with that of a commercial activated carbon in the removal of a leather dye from an aqueous solution. The adsorbents were characterized using SEM/EDAX analysis and BET surface area. The capacity of adsorption of the adsorbents was evaluated through the static method at 25°C. The results showed that the color removal was due to the adsorption and precipitation of the dye on the surface of the solids. The adsorption equilibrium was described according to the linear model for the adsorbent carbon and the equilibrium constant was 0.02 L g⁻¹. The equilibrium of adsorption on activated carbon exhibited a behavior typical of the Langmuir isotherm and the monolayer coverage was 24.33 mg g⁻¹. A mathematical model was proposed to describe the dynamics of the color removal using a fixed bed considering that the color removal is due to the adsorption and the precipitation of the dye on the adsorbent.

Keywords:

• Adsorption
• color removal
• modeling
• water treatment

Acknowledgments

The authors are grateful to CNPq/FINEP/CTHidro and Carbonífera Criciúma S.A. for financial support.