3D Composite U(VI) Adsorbents Based on Alginate Hydrogels and Oxidized Biochar Obtained from <i>Luffa cylindrica</i>
Andreas Ayiotis,
Efthalia Georgiou,
Panagiotis S. Ioannou,
Ioannis Pashalidis,
Theodora Krasia-Christoforou
Affiliations
Andreas Ayiotis
Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1 Panepistimiou Avenue, 2109, Aglantzia, P.O. Box 20537, 1678 Nicosia, Cyprus
Efthalia Georgiou
Department of Chemistry, University of Cyprus, 1 Panepistimiou Avenue, 2109, Aglantzia, P.O. Box 20537, 1678 Nicosia, Cyprus
Panagiotis S. Ioannou
Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1 Panepistimiou Avenue, 2109, Aglantzia, P.O. Box 20537, 1678 Nicosia, Cyprus
Ioannis Pashalidis
Department of Chemistry, University of Cyprus, 1 Panepistimiou Avenue, 2109, Aglantzia, P.O. Box 20537, 1678 Nicosia, Cyprus
Theodora Krasia-Christoforou
Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1 Panepistimiou Avenue, 2109, Aglantzia, P.O. Box 20537, 1678 Nicosia, Cyprus
3D naturally derived composites consisting of calcium alginate hydrogels (CA) and oxidized biochar obtained from Luffa cylindrica (ox-LC) were synthesized and further evaluated as adsorbents for the removal of U(VI) from aqueous media. Batch-type experiments were conducted to investigate the effect of various physicochemical parameters on the adsorption performance of materials. The maximum adsorption capacity (qmax) was 1.7 mol kg−1 (404.6 mg·g−1) at pH 3.0 for the CA/ox-LC with a 10% wt. ox-LC content. FTIR spectroscopy indicated the formation of inner-sphere complexes between U(VI) and the surface-active moieties existing on both CA and ox-LC, while thermodynamic data revealed that the adsorption process was endothermic and entropy-driven. The experimental data obtained from the adsorption experiments were well-fitted by the Langmuir and Freundlich models. Overall, the produced composites exhibited enhanced adsorption efficiency against U(VI), demonstrating their potential use as effective adsorbents for the recovery of uranium ions from industrial effluents and seawater.
