The influence of CO2 upon the O permeation performance of perovskite-type (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ membranes under various experimental conditions was studied. Firstly, pure CO2 was used as the sweep gas at 875C; yielding an immediate cessation of O permeation. In order to probe the reversibility of this effect, several cycles of changes of sweep gas between He and CO2 were performed. Analysis of the microstructure after permeation experiments was carried out using transmission electron microscopy, X-ray diffraction and scanning electron microscopy. It was found that both the microstructure, and the O permeation, recovered in a He atmosphere. In addition, long-term treatment with pure CO2 for 72h on the permeate side, and the effect of CO2 in the sweep gas, were explored. This showed that the perovskite structure was impaired only to a depth of up to 50μm. Furthermore, the impact of CO2 upon the feed-side was examined by adding various amounts of CO2 to the feed air.

Influence of CO2 on the Oxygen Permeation Performance and the Microstructure of Perovskite-Type (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ Membranes. M.Arnold, H.Wang, A.Feldhoff: Journal of Membrane Science, 2007, 293[1-2], 44-52