Symmetric structured porous supported mixed conductor ceramic membrane boosting oxygen permeation flux

Abstract

An effective symmetric structured dual phase mixed conducting oxygen separation membrane made of 60 wt% Ce0.9Gd0.1O2-δ − 40 wt% Ba0.5Sr0.5Co0.8Fe0.2O3-δ (60CGO-40BSCF) were prepared by the aqueous tape casting. The symmetric ceramic membranes consisted of a dense thin layer with a thickness of around 50 µm in the middle, and two porous substrates (around 290 µm thick) located on the two sides of the middle thin dense layer. In this case, both the bulk diffusion of oxygen ion and surface gas exchange are simultaneously optimized to enlarge the oxygen permeation flux. In addition, a symmetric structure favors to stabilize the ceramic membrane. Compared with monotonous dense membrane, the porous supported symmetric membrane delivered higher permeation fluxes, e.g., 3.78 ml cm−2 min−1 at 975 °C under an air/He gradient, while an oxygen permeation flux of 1.42 ml cm−2 min−1 was obtained for the monotonous dense membrane. As increasing the O2 partial pressure in the feed side to 0.8 atm, an oxygen permeation flux of 8.67 ml cm−2 min−1 was obtained. The current study implies that the porous supported symmetric membrane structure is an efficient strategy to enhance the oxygen permeation flux.