Structural characterization of Am incorporated into calcite: A TRLFS and EXAFS study

Site-selective time-resolved laser fluorescence spectroscopy of Eu3+ in calcite

“…Additionally, the lifetime of Eu(III) in site C is considerably shorter (2676 µs) in Eu:calcite II compared to Eu:calcite I and III (∼3600 µs) which might be explained by a lowering of the site symmetry. The characterization at low temperature of different Eu(III) sites in calcite is in good agreement with the low temperature TRLFS measurements performed on homogeneous doped Am(III) calcite [19]. In conclusion, the present study presents the first spectroscopic evidence that in the presence of Na + Eu 3+ is partially incorporated into the calcite lattice via the coupled substitution: An/LnNa(CO 3 ) 2 -CaCO 3 : 2Ca 2+ ↔ Na + + An 3+ /Ln 3+ .…”

“…These results are in a good agreement with the TRLFS investigation at RT of Cm(III)/calcite suspension [18] and of Am(III) resp. Cm(III)-doped calcite synthesized under identical conditions as the samples investigated here [19,33]. However, the fluorescence data obtained at RT cannot resolve all spectral features originating from Eu 3+ calcite species.…”

“…Empirical partition coefficients for rare earth elements (REE) have been determined from sorption and coprecipitation experiments [3,4,14,15]. Spectroscopic studies (EXAFS, TRLFS) on synthetic calcite crystals containing lanthanides [9,16,17] or actinides (Cm(III), Am(III)) provided structural information (coordination number, bond distances, hydration state) [18,19]. Curti et al [20] used a thermodynamic "inverse" modeling approach to model the Eu/calcite solid solution-aqueous solution (SSAS) system based on different experimental data.…”

Determination of uranium(VI) sorbed species in calcium silicate hydrate phases: A laser-induced luminescence spectroscopy and batch sorption study

“…The method has proven to be highly sensitive for the speciation of lanthanides and actinides such as Eu(III), Cm(III), Am(III) and U(VI) in aqueous solutions as well as at the solid/water interface and incorporated in bulk solid phases (e.g. [15,[28][29][30][31][32][33][34]). …”

Phase transformation in CaCO3 polymorphs: A spectroscopic, microscopic and diffraction study

“…Carbon dioxide sequestration as carbonate materials seems to be a promising way to bury billions of tons of CO 2 without the risk of release. In nuclear waste management calcite has proven to be a valuable mineral phase for the retention of highly radiotoxic actinides [5][6][7][8][9]. In this context the incorporation of the trivalent actinide curium into CaCO 3 mineral phases while retaining the host's crystal structure -the formation of a solid solution -is particularly interesting.…”