| Perovskite ceramic hollow fiber membrane for oxygen permeation has attracted considerable attention due to the 100%selectivity for oxygen and easy installation.However,the inherent brittleness of ceramic materials and the low oxygen permeation of typical perovskite materials(such as La0.6Sr0.4Co0.2Fe0.8O3-δ)have limited their ind-ustrial application.In order to solve these problems,BaCo0.85Bi0.05Zr0.1O3-δ(BCBZ)perovskite material has been developed in this paper.Highly asymmetric BCBZ cera-mic hollow fiber membrane was prepared by phase inversion/sintering technique.Aft-erwards,the BCBZ perovskite powder was used as binder to strengthen bundles.The effects of bunding on the mechanical strength,oxygen permeation and stability of the membrane were investigated.BaCo0.85Bi0.05Zr0.1O3-δ(BCBZ)powder was prepared by sol-gel method.The BCBZ powder showed a hexagonal phase structure when calcined at 950℃,which can transform into cubic perovskite phase when the temperature was rised to 11100℃.Operated at 950℃,BCBZ membrane displayed high oxygen flux up to 7.3 cm3(STP)cm-2min-1 when air with a flow rate of 200 cm3(STP)min-1 was fed in the feed side and helium with a flow rate of 150 cm3(STP)min-1 was swept in the permeate side.Such flux is obviously higher than most of the reported fluxes for typical perovskite hollow fibers.The oxygen permeation of BCBZ hollow fiber membrane decreased with the increase of CO2 concentration in the sweep gas,however,the original flux could be recovered once the sweep gas was switched back to helium.With a solution of NMP and ethanol as internal coagulation,the highly asymmetric BCBZ hollow fiber membrane with a dense layer on outer surface and porous inner surface was prepared,and the oxygen permeation flux was significantly improved.Operated at 950 ℃,BCBZ membrane displayed high oxygen flux up to 7.65 cm3(STP)cm-2min-1 when air with a flow rate of 100 cm3(STP)min-1 was fed in the feed side and helium with a flow rate of 80 cm3(STP)min-1 was swept in the permeate side,the flux doubled compared with the hollow fiber with "sandwich"structure under the same condition.We choose BCBZ perovskite materials as a binder for BCBZ membrane bundles,The average mechanical strength of the bundle composed of three hollow fiber membranes was 65.2 MPa,which was higher than 60.02 MPa of single fiber membrane.One end of the highly asymmetric BCBZ hollow fiber membrane precursor was sealed with casting solution,then cluster to membrane bludles after sintered.At 950℃,air with a flow rate of 150 cm3(STP)cm-2min-1 was fed in the feed side,and vacuuming the fiber lumen,the oxygen permeation flux reached to 6.67 cm3(STP)cm-2min-1. |
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