Electric-Field Controlled Switchable and Efficient Separation of Radioactive Xe/Kr on Borophene: A Theoretical Study.

The efficient and reversible separation of radioactive Xe/Kr during spent fuel reprocessing is important and challenging for the rapid development of nuclear energy. In this study, we firstly report a strategy of applying an electric field on the solid adsorbent borophene to realize efficient and switchable Xe/Kr separation via a density functional theory (DFT) investigation. Based on the calculational results, the adsorption energies for Xe and Kr on borophene without an electric field are -0.25 eV and -0.18 eV, respectively, indicating that Xe and Kr can only form weak adsorption on borophene. However, by applying an electric field (0.006 a.u.) to the systems, the adsorption energies for Xe and Kr on borophene are -0.98 eV and -0.47 eV, respectively, which shows that the interaction between Xe and borophene has increased dramatically compared with that of Kr, so Xe can be separated from radioactive Xe/Kr mixtures. What's more, when the electric field is removed, desorption of Xe from the surface of borophene is exothermic without an energy barrier. The adsorbent is recyclable. In summary, this theoretical study provides novel information for experimental researches, the highly efficient Xe/Kr separation can be controlled by turning on/off the applied electric field.