Phase structure and aqueous stability of TRPO waste incorporation into Gd2Zr2O7 pyrochlore

The present work explores the potential of Gd 2 Zr 2 O 7 pyrochlore based materials for incorporation of trialkyl phosphine oxides (TRPO) waste which is a mixture of multi-nuclides with multi-valence. A series of (Gd,A) 2 (Zr,B) 2 O 7 ceramics were synthesized to investigate the influence of multi-nuclides incorporation on phase structure and aqueous stability of Gd 2 Zr 2 O 7 . XRD and BSE results show that all the ceramics exhibit a single pyrochlore structure. Raman spectroscopy reveals that the degree of structural order for (Gd,A) 2 (Zr,B) 2 O 7 solid solutions increases with enhanced TRPO waste content. In addition, aqueous stability testing was carried out using the MCC-1 static leach test method. The results demonstrate that the normalized release rates of the elements in TRPO waste are kept in a low value below 10 −4   g   m −2   d −1 . La shows the highest normalized release rate of all the involved elements, while Zr exhibits the best chemical stability.