| Abstract Scope |
In borosilicate nuclear waste glasses, MoO3 exhibits very low loading limits (<1wt%). Above this limit, MoO3 can promote phase separation and form water-soluble alkali molybdates, like Na2MoO4, reducing chemical durability. In contrast, phosphate glasses accommodate significantly higher MoO3 contents. Studies suggest B2O3 addition enhances Mo incorporation in phosphate glasses, which was first hypothesized to result from B-O-Mo linkages, though structural evidence remains limited.This study investigates the structural role of B2O3 in aluminoborophosphate glasses and its impact on MoO3 incorporation. Three glass series were designed in the pyrophosphate region (O/P = 3.53), where B2O3 progressively replaces Al2O3. Here, we show that B2O3 addition significantly increases MoO3 incorporation in the aluminoborophosphate matrix. Using Raman spectroscopy, EPR, and MAS NMR, this study elucidates the structural changes and identifies the mechanisms responsible for the enhanced Mo loading. |