Abstract
The coordination of crystalline products resulting from the co-crystallization of Np(vi), Pu(vi), Am(vi), and Np(v) with uranyl nitrate hexahydrate (UNH) has been revealed through solid-state spectroscopic characterizationviadiffuse reflectance UV-Vis-NIR spectroscopy, SEM-EDS, and extended X-ray absorption fine structure (EXAFS) spectroscopy. Density functional and multireference wavefunction calculations were performed to analyze the An(vi/v)O2(NO3)2·2H2O electronic structures and to help assign the observed transitions in the absorption spectra. EXAFS show a similar coordination between the U(VI) in UNH and Np(vi) and Pu(vi); while Am resulted in a similar coordination to Am(iii), as reduction of Am(vi) occurred prior to EXAFS data being obtained. The co-crystallization of the oxidized transuranic species—penta- and hexavalent—with UNH, represents a significant advance from not only a practical standpoint in providing an elegant solution for used nuclear fuel recycle, but also as an avenue to expand the fundamental understanding of the 5f electronic behavior in the solid-state.
| Original language | English |
|---|---|
| Pages (from-to) | 13228-13241 |
| Number of pages | 14 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 23 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 21 2021 |
Funding
This work was sponsored by the Nuclear Energy University Program, Office of Nuclear Energy, US Department of Energy, under Award No. DE-NE0008653, for which the authors are very grateful. V. S. B. was in part supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division for conducting EXAFS data processing and fitting. DFT optimization was performed using resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231. J. A. acknowledges support from the US Department of Energy, Office of Science, Basic Energy Sciences, Heavy Elements Chemistry program, under Award Number DE-SC0001136, for TD-DFT and WFT calculations and analyses. We thank the Center for Computational Research (CCR) at the University of Buffalo for providing computational resources. We would also like to acknowledge the Advanced Photon Source Sector 12BM-B at Argonne National Laboratory, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division, under the contract No. DE-AC02-06CH11357. We also acknowledge Dr Bruce A. Moyer at Oak Ridge National Laboratory for fruitful discussions on experimental design. We want to acknowledge Dr Luis H. Ortega of the Fuel Cycle and Materials Laboratory in the Department of Nuclear Engineering at Texas A&M University who aided in obtaining the SEM images and EDS measurements. This work was sponsored by the Nuclear Energy University Program, Office of Nuclear Energy, US Department of Energy, under Award No. DE-NE0008653, for which the authors are very grateful. V. S. B. was in part supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division for conducting EXAFS data processing and fitting. DFT optimization was performed using resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy?Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231. J. A. acknowledges support from the US Department of Energy, Office of Science, Basic Energy Sciences, Heavy Elements Chemistry program, under Award Number DE-SC0001136, for TD-DFT and WFT calculations and analyses. We thank the Center for Computational Research (CCR) at the University of Buffalo for providing computational resources. We would also like to acknowledge the Advanced Photon Source Sector 12BM-B at Argonne National Laboratory, which is supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division, under the contract No. DE-AC02-06CH11357. We also acknowledge Dr Bruce A. Moyer at Oak Ridge National Laboratory for fruitful discussions on experimental design. We want to acknowledge Dr Luis H. Ortega of the Fuel Cycle and Materials Laboratory in the Department of Nuclear Engineering at Texas A&M University who aided in obtaining the SEM images and EDS measurements.
| Funders | Funder number |
|---|---|
| Department of Nuclear Engineering at Texas A&M University | |
| U.S. Department of Energy?Office of Science | |
| U.S. Department of Energy | DE-NE0008653 |
| NIH Office of the Director | S10OD024973 |
| Office of Science | |
| Office of Nuclear Energy | |
| Basic Energy Sciences | DE-AC02-06CH11357 |
| Argonne National Laboratory | |
| Lawrence Berkeley National Laboratory | DE-AC02-05CH11231, DE-SC0001136 |
| Nuclear Energy University Program |