The removal of amoxicillin from wastewater using organobentonite

Organobentonites used as absorbents to remove amoxicillin from wastewater have been investigated here because they are effective in removing organic pollutants. It is evident that bentonite modified with hexadecyl trimethyl ammonium (DK1) can effectively remove amoxicillin from aqueous solution. Batch experiments showed that the adsorption of amoxicillin onto DK1 fitted well to a pseudo second-order kinetic model with corresponding rate constants (0.0187 g/mg min at 20 degrees C). The Langmuir isotherm provided the highest adsorption capacity (2638 mg/g at 20 degrees C). Our thermodynamic study suggested that the adsorption of amoxicillin onto DK1 was physisorptive and endothermic in nature. Furthermore DK1 was characterized by scanning electronic microscopy (SEM), Specific Surface Area (SSA), X-ray powder diffraction (XRD) and Fourier Transform Infrared (FTIR) spectrometer. These characterizations provided evidence of the morphological properties and how well the adsorption process performed. An adsorption mechanism including both ion-exchange and partition was proposed. Finally, DK1 was used to remove amoxicillin from wastewaters and the results showed 81.9% and 87.5% of amoxicillin was removed at 19.0 mg/L and 2.0 mg/L, respectively. (C) 2013 Elsevier Ltd. All rights reserved.