The precipitation of aluminum (oxy)hydroxides including boehmite (γ-AlO(OH)) and gibbsite (γ-Al(OH)<sub>3</sub>) is a major part of industrial applications like alumina refinement and the nuclear waste process at the Hanford Site, WA. The liquid/mineral interfaces have been widely studied at the basal surface while the edges have been largely unexplored despite most phenomena, such as crystal growth and dissolution, occurring at the edges. In this work we investigated the interface between water and the basal surface in addition to the predominant, low Miller index, edges of boehmite and gibbsite through the use of classical and ab initio molecular dynamics in addition to static density functional theory (DFT) calculations. Several unique adsorption modes of water have been identified at each surface, with adsorption mode population dependent on the surface termination. MD simulations provided the geometries for the calculation of DFT binding energies of adsorption modes on the basal plane suggest a statistically significant difference in energies. Additionally, the dynamics at the interface has been examined to study the reorientational and translational behavior of water molecules within the first hydration layer as well as the diffusion of water away from the surface. Understanding pure water’s structure and dynamics at the interface is an initial step in understanding the perturbation of the surface due to the electrolyte in highly alkaline conditions.

Interfacial organization and diffusion of water at surfaces of boehmite (γ-AlO(OH)) and gibbsite (γ-Al(OH)<sub>3</sub>) with low miller indices

2019 Fall National Meeting

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Interfacial organization and diffusion of water at surfaces of boehmite (γ-AlO(OH)) and gibbsite (γ-Al(OH)3) with low miller indices

Interfacial organization and diffusion of water at surfaces of boehmite (γ-AlO(OH)) and gibbsite (γ-Al(OH)₃) with low miller indices