Adsorption of hexavalent chromium by novel chitosan/poly(ethylene oxide)/permutit electrospun nanofibers

Abstract

Chitosan/poly(ethylene oxide)/permutit (CS/PEO/PT) composite nanofibers were prepared via electrospinning and their potential application in the removal of hexavalent chromium (Cr(VI)) from aqueous solutions was studied in detail. SEM results showed that the nanofibers were homogeneous and bead-free. XRD and DSC results demonstrated that there were strong interactions among CS, PEO and PT. The solubility test showed that the CS/PEO/PT composite membrane had excellent durability in water. The CS/PEO/PT-1% nanofibers exhibited the best adsorption performance for Cr(VI) ions in acidic solution (pH = 3) and at a low Cr(VI) concentration of 50 mg L⁻¹. The maximum adsorption capacity reached 208 mg g⁻¹. The adsorption kinetics and equilibrium data were well described by pseudo-second-order kinetic and Langmuir isotherm models, respectively. According to the results of FTIR and XPS analyses, protonation, ion exchange, electrostatic interactions and redox reactions were involved in the adsorption process. All the results indicated that the electrospun CS/PEO/PT nanofibers could be used as promising absorbents for the removal of Cr(VI).