Separation of Radiolytic Species at the Boehmite-Water Interface

The effects of radiation fields present in nuclear waste tanks on the structure and reactivity of Al-bearing phases, a major component of the solid waste inventory, and their implications for nuclear waste processing remain poorly understood. While H2 release from irradiated Al-(oxy)hydroxide phases can be measured experimentally, the mechanisms that lead to its formation and the fate of other radiolytic species are not known. Density functional theory calculations were therefore performed to determine the energetics of radiolytic species (O– and H0) across the interface between water and both the (010) and (101) facets of boehmite (γ-AlOOH), the two surfaces that dominate the morphology of boehmite particles at alkaline pH values relevant to tank waste. The DFT calculations employed semilocal and hybrid exchange-correlation functionals and consisted of a combination of energy minimizations and ab initio molecular dynamics simulations. The calculations showed that the release of H0 radicals from boehmite ...