Enhanced fluoride adsorption from aqueous solution by zirconium (IV)-impregnated magnetic chitosan graphene oxide

In this study, zirconium (IV)-impregnated magnetic chitosan graphene oxide (Zr-MCGO) was synthesized for removing fluoride from aqueous solution in batch mode. Characterization approaches (pH(pzc), FTIR, SEM, XRD, VSM, Raman, BET, and XPS) proved the successful incorporation of Zr into the adsorbent. Zr-MCGO exhibited a relatively favorable and stable capacity of defluoridation at lower pH with a wide range of pH from 4.0 to 8.0, while there was slightly negative effect of ionic strength on adsorption. In addition, Elovich kinetic model and Koble-Corrigan isotherm model could describe the uptake of fluoride well. The adsorption capacity was 8.84 mg/g at 313 K and Zr-MCGO was easily separated from mixtures using external magnet. Based on the experiments and XPS, electrostatic force, ligand exchange, and Lewis acid-base interaction might be potential adsorption mechanisms. Pseudo-second-order model was more compatible with the desorption process by 0.01 mol/L NaHCO3 solution. Therefore, Zr-MCGO was a promising candidate for defluoridation on wastewater pollution remediation. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Zirconium (IV)-impregnated magnetic chitosan graphene oxide (Zr-MCGO) was synthesized to remove fluoride from aqueous solution in batch mode. The study showed that Zr-MCGO exhibited good defluoridation capacity at different pH levels, could be easily separated using an external magnet, and potential adsorption mechanisms include electrostatic force, ligand exchange, and Lewis acid-base interaction.