| Autor: |
Zhao Y; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Chen P; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Wang X; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Hlushko H; Radiation Laboratory and Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, United States., LaVerne JA; Radiation Laboratory and Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, United States., Liu L; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Pearce CI; Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.; Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164, United States., Wang Z; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.; Department of Chemistry, Washington State University, Pullman, Washington 99164, United States., Rosso KM; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States., Zhang X; Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States. |
| Abstrakt: |
Here, we examine how radiation impacts the dissolution behavior of boehmite by subjecting dry nanoparticles of different sizes to 60 Co γ radiation and subsequently analyzing their dissolution behavior in caustic solutions as a function of temperature. The measured kinetics show that irradiation with an amount 228.24 Mrad significantly slows the dissolution rate, particularly for smaller sizes at lower temperatures. Specifically, the temperature-dependent dissolution rates of irradiated 20 nm boehmite versus pristine material in 3 M NaOH solutions were several times lower (e.g., rate constant of 0.026 vs 0.075 h -1 at 60 °C), with an apparent activation energy 40 kJ mol -1 higher. Although various imaging techniques and X-ray diffraction measurements consistently revealed no obvious differences between pristine and irradiated samples, after irradiation significant binding energy shifts were detected in the X-ray photoelectron Spectroscopy peaks of Al 2p and O 1s, and a change in their relative intensities indicated a lower O/Al ratio. This suggests that γ-irradiation may stabilize boehmite particle surfaces by driving their chemistry and structure toward more stable aluminum oxide forms. This finding may help explain slower dissolution rates of boehmite in nuclear waste and may be useful for the development of more robust predictive models and effective strategies for waste processing. |
