Preparation of Oxygen Ion Conducting Ceramic Hollow-Fiber Membranes

Hollow-fiber membranes of mixed conducting perovskite Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ) were prepared using a sequence of extrusion, gelation, and sintering steps. For this purpose, a finely divided mixture of the component oxides was prepared by the modified Pechini technique and suspended in a polymer solution. The suspension was extruded through a spinneret and gelled in water. The resulting fiber was first heated at 800 °C to remove the polymer and then at 1100 °C to form the perovskite and simultaneously sinter the particles to a gastight membrane. The fibers were characterized by scanning electron microscopy and tested for air separation at ambient pressure and temperature between 700 and 950 °C. The maximum oxygen flux measured was 3.9 mL/min/cm^2 at 950 °C and 0.022 atm of average permeate oxygen partial pressure.