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Article Dans Une Revue Journal of Materials Chemistry A Année : 2023

Iodine dissolution mechanisms in high-pressure aluminoborosilicate glasses and their relationship to oxygen speciation

Résumé

Incorporation of iodine(I) into high-pressure vitrified glasses appears to be a potential solution for the immobilization of 129I radioisotopes. Under these conditions, I dissolution is strongly enhanced; however, the impact I dissolution has on the glass structure remains to be determined to assess the matrix durability. We have experimentally studied the change in I solubility and speciation in a series of sodium aluminoborosilicate glasses (Na2O ranging from 10 to 40 mol%) held at 0.25 and 1.0 GPa and 1250 °C. As expected, the I solubility increases with pressure and with increasing Na2O and is positively correlated with the glass optical basicity. The I speciation determined by XPS is changing with the initial loaded source of iodine (either I2 or I2O5) with a predominant iodide form (I−) in the glass structure. The investigation of the oxygen environment in the I-bearing glasses using O 1s XPS revealed that I dissolution induces an apparent oxygen loss within the glass structure. This result is consistent with our current view on I dissolution mechanisms. Furthermore, the subsequent simulations of the O 1s XPS spectra suggest that I dissolution consumes non-bridging oxygen to form bridging oxygen. This change in the oxygen speciation points toward an increase in the glass durability, which is an important aspect for nuclear waste immobilization
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Dates et versions

hal-04271370 , version 1 (06-11-2023)

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Yann Morizet, Sami Soudani, Jonathan Hamon, Michael Paris, Carole La, et al.. Iodine dissolution mechanisms in high-pressure aluminoborosilicate glasses and their relationship to oxygen speciation. Journal of Materials Chemistry A, 2023, 11 (42), pp.22891-22905. ⟨10.1039/d3ta05344j⟩. ⟨hal-04271370⟩
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