Structural investigation of borosilicate glasses containing lanthanide ions

Area of Science:

• Materials Science
• Nuclear Chemistry
• Solid State Chemistry

Background:

• Radioactive waste immobilization requires inert matrices.
• Borosilicate glasses are promising candidates for immobilizing high-level radioactive waste.
• Understanding actinide incorporation in glass is crucial for safe disposal.

Purpose of the Study:

• To investigate the structural effects of lanthanide (Ln) addition to a simplified borosilicate glass matrix.
• To use lanthanides (Ce, Nd, Eu) as chemical surrogates for actinides.
• To assess the suitability of borosilicate glass for actinide immobilization.

Main Methods:

• Neutron diffraction combined with Reverse Monte Carlo simulations.
• ¹¹B Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy.
• Raman spectroscopy.

Main Results:

• All glass structures contained tetrahedral SiO₄, trigonal BO₃, and tetrahedral BO₄ units.
• Lanthanide addition promoted BO₃ to BO₄ isomerization, altering boron speciation.
• Lanthanides were found to occupy both Si and B sites within the glass matrix.

Conclusions:

• Borosilicate glass effectively incorporates lanthanide ions.
• The glass matrix structure is adaptable to accommodate lanthanides, suggesting similar behavior for actinides.
• This research supports the use of borosilicate glass for immobilizing radioactive nuclear waste containing actinides.