Iron oxide/carbon nanotubes/chitosan magnetic composite film for chromium species removal.

An adsorbent in the form of a CLCh/MWCNT/Fe film was prepared using multiple walled carbon nanotubes (MWCNT) doped with magnetic iron oxide and deposited in crosslinked chitosan (CLCh). The CLCh/MWCNT/Fe was characterized by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), nitrogen (N) adsorption/desorption, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Infrared Spectroscopy (IR) and Raman Spectroscopy. The CLCh/MWCNT/Fe film presented a maximum adsorption capacity for Cr(III) of 66.25 mg/g (150 min) and for Cr(VI) of 449.30 mg/g (60 min) at 25 °C. The CLCh/MWCNT/Fe can be easily removed from the aqueous solution by a mechanical separation or by magnetization due to its magnetic properties. In ten consecutive reutilization adsorption cycles the CLCh/MWCNT/Fe film presented efficiency losses of only 12% and 6% for the removal of Cr(III) and Cr(VI), respectively.