Preparation and characterization of chitosan/kaolin/Fe3O4 magnetic microspheres and their application for the removal of ciprofloxacin

Abstract

In this study, a magnetically separable adsorbent [chitosan (CTS)/kaolin/Fe3O4 magnetic microspheres] was prepared by emulsion crosslinking. The prepared microspheres were characterized by Fourier transform infrared spectroscopic analysis, vibrating sample magnetometry, X-ray diffraction, transmission electron microscopy, energy-dispersive spectrometry, thermogravimetric analysis and scanning electron microscopy. The synthesized microspheres were used as adsorbents for the removal of ciprofloxacin (CIP) from an aqueous solution. Adsorption of CIP from the aqueous solution was investigated in terms of adsorbent dose, initial pH (pH0) and initial concentration. The optimal pH0 for CIP adsorption was found to be 6. Highest adsorption capacity was achieved with an adsorbent dose of 15 mg. The adsorption kinetics were well described by the pseudo-second-order equation and the adsorption isotherms were fitted to the Langmuir model. Reusability experiments using CTS/kaolin/Fe3O4 magnetic microspheres showed that the adsorption capacity of these microspheres had no observable deterioration in performance even after four repeated cycles. Results of the adsorption-desorption experiments suggest that CTS/kaolin/Fe3O4 microspheres can be used as promising adsorbents for removing CIP from wastewater.