Re-evaluation of La0.6Sr0.4Co0.2Fe0.8O3-δ hollow fiber membranes for oxygen separation after long-term storage of five and ten years

Abstract As a typical example of the mixed ionic and electronic conducting ceramics, perovskite oxide La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) membrane has been widely studied for a possible cost-effective method for oxygen separation to replace the conventional cryogenic distillation technique. LSCF membrane displays good stability and satisfactory oxygen flux for commercial considerations. In this work, LSCF hollow fiber membranes had been purposely stored in laboratory for 5 and 10 years. These decade LSCF membranes were re-evaluated and characterized to examine the influence of storage on the membrane performance. The 10-year-storage does not exert obvious negative influence on the mechanical strength but significantly reduced the oxygen flux by 77.6% compared to the fresh membrane. The oxygen reduction is due to the impurity like carbonate (SrCO3) formation on the membrane surface during the long-term storage in air. However, the formed impurity layer on membrane surface only has a penetration depth around 7 μm. Thus, the oxygen flux of the membrane can be easily recovered by reactivation via heat-treatment or room temperature acid-etching reaction to remove these impurities. This research further confirms the stability of La0.6Sr0.4Co0.2Fe0.8O3-δ membranes for practical applications.