| Affiliation: | 1. Department of Chemistry, University of Cyprus, Nicosia, Cyprus;2. Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus;3. Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Romanian Academy – Timisoara Branch, Timisoara, Romania;4. Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Romanian Academy – Timisoara Branch, Timisoara, Romania Research Center for Complex Fluids Systems Engineering, Politehnica University of Timisoara, Timisoara, Romania;5. Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, Bucharest, Romania;6. Applied Physics Department, National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Romania |
| Abstract: | Magnetoactive 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. |
