Superparamagnetic polyvinylpyrrolidone/chitosan/Fe3O4 electrospun nanofibers as effective U(VI) adsorbents

Abstract

AbstractMagnetoactive electrospun fibrous membranes consisting of polyvinylpyrrolidone (PVP), chitosan (CS) and pre‐fabricated, double‐layer oleic acid‐coated magnetite nanoparticles (OA.OA.Fe3O4) were fabricated and evaluated as new adsorbent materials for the removal and recovery of uranium (U(VI)) from aqueous solutions. The adsorption has been investigated by batch‐type experiments and the solid material has been characterized by X‐ray diffraction spectroscopy (XRD), Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy/energy dispersive X‐ray analysis (TEM/EDX) and vibration sample magnetometry (VSM) measurements prior and after uranium adsorption. The experimental adsorption data were found to be well fitted with the Langmuir isotherm and the pseudo‐second order kinetic model. The results indicate that PVP/CS/OA.OA.Fe3O4 fibrous adsorbents exhibit good adsorption properties towards U(VI) in aqueous solutions, achieving a qmax value of 0.77 mol kg−1 (183.3 mg g−1) at pH 6.0. The experiments regarding the regeneration and reuse of the magnetoactive adsorbents were carried out using Na2CO3, at pH ~11. After four cycles, the percentage relative adsorption remained stable (~100%) whereas the desorption percentage decreased from 31.9% to 21.0%. Generally, the presented results demonstrate that the incorporation of the Fe3O4 NPs has a positive effect on the adsorption efficiency of U(VI) from aquatic environments.