Preparation and characterization of mixed-conducting supported hollow fiber membrane

Sr_0.7Ba_0.3Fe_0.9Mo_0.1O_3-δ (SBFM) hollow fiber supports were prepared by dry-wet spinning technology. SrCo_0.8Fe_0.2O_3-δ doped Nb₂O₅ (SCFNb) was selected as membrane material, SCFNb/SBFM supported hollow fiber membranes were successfully prepared by a combined spin-spraying and co-sintering method. XRD, SEM, thermal expansion technique, oxygen permeability and membrane reaction tests were utilized to characterize the crystal phase structures, microstructure, sintering behavior, oxygen permeation flux, and reaction performance of membranes and/or supports, respectively. XRD patterns show that the membranes and supports are composed of perovskite main phase. SEM images indicate that the support has an asymmetric structure with a sponge-like microporous/finger-like porous structure. The membrane surface is dense and crack-free, and the membrane layer with a thickness of about 5 μm is well bonded with the support. At 900℃, the oxygen permeation flux of the membrane is 0.74 mL/(cm²·min). No degradation of performance is observed in the membrane reactor under partial oxidation of methane during continuously operating for 200 h at 850℃, and the oxygen permeation flux can reach 4.5 mL/(cm²·min). It is demonstrated that the SCFNb/SBFM supported hollow fiber membrane exhibits high oxygen permeation flux and good stability of the membrane reactor.