An uranyl sorption study inside functionalised nanopores

U Pinaeva; N Ollier; O Cavani; E Balanzat; M Al-Sheikhly; T L Wade; M-C Clochard

doi:10.1038/s41598-020-62792-4

An uranyl sorption study inside functionalised nanopores

Sci Rep. 2020 Apr 1;10(1):5776. doi: 10.1038/s41598-020-62792-4.

Authors

U Pinaeva¹, N Ollier¹, O Cavani¹, E Balanzat², M Al-Sheikhly³, T L Wade¹, M-C Clochard⁴

Affiliations

¹ Laboratoire des Solides Irradiés CEA-CNRS-Ecole Polytechnique UMR7642, Institut Polytechnique de Paris, 91128, Palaiseau Cedex, France.
² CIMAP, CEA-CNRS-ENSICAEN UMR6252, 14050, Caen Cedex, France.
³ Laboratory for Radiation and Polymer Science, Department of Materials Science and Engineering A. J. Clark School of Engineering, University of Maryland, College Park, MD, 20742-2115, USA.
⁴ Laboratoire des Solides Irradiés CEA-CNRS-Ecole Polytechnique UMR7642, Institut Polytechnique de Paris, 91128, Palaiseau Cedex, France. marie-claude.clochard@polytechnique.edu.

Abstract

Sorption mechanism of uranyl by poly(bis[2-(methacryloyloxy)ethyl] phosphate) (PB2MP) functionalised polyvinylidene fluoride (PVDF) track-etched membranes, PB2MP-g-PVDF, was investigated. It was found that uranyl sorption obeyed Langmuir isotherm model giving a maximum U(VI) membrane uptake of 6.73 μmol g^-1 and an affinity constant of 9.85 ⋅ 10⁶ L mol^-1. XPS and TRPL measurements were performed to identify sorbed uranyl oxidation state and its environment. Uranyl was found to be mainly in its hexavalent state, i.e. U(VI), showing that the trapping inside the PB2MP-g-PVDF nanoporous membranes did not change the ion speciation. Two sorbed uranyl life-times (τ₁ = 8.8 μs and τ₂ = 102.8 μs) were measured by TRPL which pointed out different complexations taking place inside the nanopores. Uranyl sorption by PB2MP-g-PVDF membranes was also found to be pH dependent demonstrating the highest performance at circumneutral pH. In addition, TRPL was demonstrated to be not only a remarkable technique for U(VI) characterization, but also an alternative to voltammetry detection for trace on-site uranyl monitoring using PB2MP-g-PVDF nanoporous membranes.

Abstract

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