Oxygen separating membrane manufactured from Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite-like material

Abstract

The dense thin membrane for oxygen separation was manufactured from Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) mixed oxide with perovskite-like structure prepared by the solid-state method. Properties of both powder and granulate (chemical and phase compositions, the specific surface area and the porosity) as well as sintered material (the apparent density, the apparent porosity, the water absorbability, the chemical composition, the crystallographic structure and microstructure), that affect the process of ion oxygen permeation through membrane, were determined. Parameters influencing on usable properties of membranes viz., the bending strength and the coefficient of thermal expansion were assessed as well. Effect of the sintering temperature on membrane structure was evaluated. The elaborated fabrication procedure enables one to manufacture membrane, in which microstructure is characterized by the presence of big grains as well as decreased concentration of grain boundaries. Measurements of the oxygen permeation through BSCF membrane revealed that the highest oxygen flux reaching 2.6 cm3 O2/(cm2 min) was obtained at 950°C under air and helium flows equal to 1 dm3 min-1.