Facile Fabrication of Magnetic Chitosan Beads of Fast Kinetics and High Capacity for Copper Removal

In this study, magnetic chitosan (CS) beads of similar to 200nm in diameter were successfully prepared by a facile one-step method. The resultant composite Fe3O4-CS was characterized using transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Its adsorption toward Cu(II) ions was investigated as a function of solution pH, CS dosage, Cu(II) concentration, and contact time. The maximum capacity of Fe3O4 CS was 129.6 mg of Cu(II)/g of beads (617.1 mg/g of CS). More attractively, the adsorption equilibrium could be achieved within 10 min, which showed superior properties among the available CS-based adsorbents. Continuous adsorption desorption cyclic results demonstrated that Cu(II)-loaded Fe3O4-CS can be effectively regenerated by ethylenediaminetetraacetic acid (EDTA) solution, and the regenerated composite beads could be employed for repeated use without significant capacity loss. Additionally, Fe3O4 CS beads can be readily separated from water within 30 s under a low magnetic field (<0.035 T).