Removal of enrofloxacin from aqueous solutions using illite and synthetic zeolite X

Resumo

Enrofloxacin uptake and removal from aqueous solutions using illite and synthetic zeolite X prepared from illite, were studied in batch experiments under varying pH, contact time, and initial enrofloxacin concentrations. The X-ray diffraction and Fourier transform infrared spectroscopy caracterization were used to analyse the enrofloxacin adsorption in order to elucidate the adsorption mechanisms. It was found that enrofloxacin could be efficiently removed at pH 7 and pH 8 for clay and zeolite X, respectively. In addition, the second order model of kinetics is more adopted for the two samples. The isotherms of adsorption of enrofloxacin by illite and zeolite X show that the latter has the twice higher adsorption capacity of the clay. Equilibrium data fit well with the Langmuir and Freundlich isotherms. Moreover, the cation exchange, the electrostatic interaction, the cation bridging and the formation of bidentate ligands were the possible mechanisms of the enrofloxacin retention.