Removal of sulfate from aqueous solution by magnetic chitosan microspheres

Abstract

The magnetic chitosan microspheres (Fe3 O4 /CS) were prepared by inverse suspension cross-linking and characterized by scanning electron microscope, optical micrographs, Fourier transform infrared spectrophotometer, and X-ray diffraction. They were employed as the adsorbents for the removal of sulfate from the aqueous solutions in the batch system. The magnetic material (Fe3 O4) used in the preparation of the magnetic chitosan microspheres was prepared by precipitation from FeCl2 and FeCl3 solutions in the basic medium. The experimental results showed that Fe3 O4 /CS was an excellent adsorbent for the removal of sulfate with an adsorption capacity of 256.41 mg g–1. Equilibrium isotherm study showed a good agreement with the Langmuir isotherm equation for the monolayer adsorption process, while the adsorption process can be well described by the second-order kinetic model and the Dubinin–Radushkevich isotherm further confirmed the presence of physical adsorption forces.