Zirconium stabilized Ba 0.5Sr 0.5(Co 0.8− xZr x)Fe 0.2O 3− α perovskite hollow fibre membranes for oxygen separation

Abstract

Ba 0.5Sr 0.5(Co 0.8− x Zr x )Fe 0.2O 3− α ( x = 0.0–0.3) (BSCZxF) ceramic powders were synthesized via an improved EDTA-citric acid complexing method. The BSCZxF ( x = 0.05, 0.1, 0.2) perovskite hollow fibre membranes were fabricated from the powders through a phase-version/sintering technique. The oxygen permeation properties of the hollow fibre membranes were measured under air/He gradients at 700–950 °C. Experimental results have shown that the composites with x = 0.05–0.20 Zr-doping content exhibit pure cubic perovskite structure but the BSCZ 0.30F oxide contains impurity phases. Due to the substitution of zirconium in Co sites, the phase stability, the mechanical strength and the densification properties of the BSCZxF hollow fibre membranes are improved noticeably. However, the oxygen permeation flux of the BSCZxF membranes decreases with increased activation energy as the Zr-doping content is increased from 0.05 to 0.20. The suitable Zr-doping content should be around x = 0.1 in order to obtain both high permeation fluxes and high permeation stability.