(628r) Investigation of Nitrogen Transport within Group V Metals for Nitrogen-Selective Membranes

Nitrogen (N₂)-selective membranes may be a promising technology for separating N₂ as to effectively create a stream of CO₂ for indirect carbon capturefrom flue gas. Another application is for O₂ production through the selective separation of N₂ from air. Additionally, successful implementation of this technology may provide a route to carry out ammonia synthesis at lower energy, compared to the traditional Haber-Bosch process. The goal of this study is to investigate vanadium (V) metals and their alloys as dense membrane materials to obtain improved diffusion of atomic nitrogen. Density functional theory-based theoretical calculations are carried out on the investigation of N₂ binding at different interstitial sites of the V crystal. Nitrogen was not found to be stable at T-sites within the bulk V lattice, but stable at O-sites only. Strong attachment of nitrogen to the bulk of vanadium is modified by ruthenium (Ru) alloying at various concentrations for optimized N diffusion. Bader charge analysis is employed to investigate charge-transfer mechanisms associated with bulk nitrogen absorption. In addition to the theoretical modeling, N₂ permeation experiments have also been carried out to determine the permeabilities of membrane foils comprised V at different temperatures.

Results will be presented on the bulk transport of nitrogen in vanadium and vanadium-based alloys as a function of nitrogen concentration and Ru alloying.