Effect of ph on the removal of fluoxetine from aqueous solutions by granular activated carbon

Abstract

The widespread use of pharmaceuticals in human and veterinary medicine has led to the continuous release of these micropollutants and their metabolites into environmental matrices. The aim of this work is to assess the sorption capacity of activated carbon and to evaluate the effect of the solution pH on the removal of fluoxetine from dilute solutions (5 mg/L). Kinetic assays were performed in batch experiments at different pH values, from 2 to 9. The pH of zero point of charge, pHzpc, obtained for activated carbon was 8.3. The results revealed that the solution pH strongly influences the electrostatic interactions between the net surface charge of the adsorbent and the electric charge of fluoxetine molecules. The adsorption of fluoxetine onto activated carbon was therefore dependent on the solution pH, being the maximum uptake attained at pH 9 (q = 48.5 mg/g).