Sulfamethoxazole Removal from Synthetic Solutions by Ion Exchange using a Strong Anionic Resin in Fixed Bed

Abstract

Numerous antibiotics like sulfonamides have been found in effluents from drug manufacturers due to the fact that these pollutants cannot be removed completely in STPs. Removal of pharmaceuticals by adsorption and ion exchange comprise some of the most promising techniques due to their low cost, easy regeneration, and selective removal of pollutants. This article studies the removal of sulfamethoxazole (SMX), a common antibiotic that prevents the formation of dihydrofolic acid and which is the most frequently detected as sulfonamide in municipal sewage. The SMX retention capacity of an anionic ion exchange resin, Lewatit MP-500 (Lanxess Chemical), was initially determined. Equilibrium and kinetics were studied and equilibrium constants and diffusivity values were obtained using different models. Load and elution breakthrough curves were plotted to evaluate ion exchange operation in a fixed bed column. In the elution step, 100% SMX was recovered in all cycles and could be concentrated up to nine times, thus facilitating the treatment of this compound. Load and elution breakthrough curves were simulated using a fixed bed model in which axial dispersion was considered the parameter model fit. A good correlation between experimental results and the numerical solution of the fixed bed model demonstrates the validity of the model.