Preparation and characterization of novel magnetic Fe3O4/chitosan/Al (OH)(3) beads and its adsorption for fluoride

A novel magnetic bioadsorbent beads composed of Fe3O4, chitosan, and Al (OH)(3) (Fe3O4/CS/Al(OH)(3)) was synthesized by a modified solvothermal and in-situ reaction. The composite adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and vibrating sample magnetometer, respectively. Adsorption toward F- onto Fe3O4/CS/Al(OH)(3) was investigated as a function of Fe3O4 concentration, initial solution pH, adsorbent dosage, initial fluorion concentration, co-existing ions in water and initial temperature. The addition of Fe3O4 could enhance the adsorption properties of CS/AI(OH)(3). The saturated adsorption capacity of magnetic Fe3O4/CS/AI(OH)(3) calculated from the Langmuir isotherm model was 76.63 mg/g at 298 K. The adsorption isotherm of F- followed Langmuir isotherm model and the adsorption kinetics fitted better to the pseudo-second order kinetic model. The influence of temperature confirmed that the adsorption was spontaneous and endothermic. The magnetic Fe3O4/CS/Al(OH)(3) beads could be easily separated from water under a low magnetic field. (C) 2018 Elsevier B.V. All rights reserved.