Removal of Chromium(VI) from Aqueous Solution Using a Novel Green Magnetic Nanoparticle – Chitosan Adsorbent

Abstract

A nanocomposite (ION-CS) consisting of magnetite nanoparticles (ION) physically mixed with chitosan (CS) was synthesized by a green protocol in order to investigate the adsorption of hexavalent chromium Cr(VI) from synthetic aqueous solutions. X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to characterize the ION-CS nanomaterial in comparison with magnetite. Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy, absorption spectroscopy, and equilibrium sorption of Cr(VI) on ION-CS and CS described by the Langmuir and Freundlich isotherm models were investigated. Finally, the reusability of the ION-CS nanomaterial was investigated by successive three sorption/desorption cycles. The results revealed that the magnetite nanoparticles were entrapped into the chitosan matrix, having an average particle size in the range from 10 to 15 nm. The removal of Cr(VI) by ION-CS and CS was explored; a significant enhancement in the percentage of Cr(VI) removed was obtained using the ION-CS nanomaterial. The remarkable sorption capacities and high reusability and stability of the ION-CS nanomaterial suggest the promising potential of this novel sorbent for the removal of Cr(VI).

Keywords:

• Adsorption
• atomic force microscopy (AFM)
• attenuated total reflectance (ATR) – Fourier transform infrared spectroscopy (FTIR)
• chitosan
• chromium removal
• magnetic nanoparticles
• dynamic light scattering (DLS)

Additional information

Funding

The work has been funded by Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii through POC Program, Project no. 49/2016, ID P_37_649 and PNIII Program, project no. 7PTE/2016 and the complex project PNCDI-III-P1-1.2-PCCDI-2017-0245, Contract 26PCCDI/2018.