Double-layer ceramic-carbonate hollow fiber membrane with superior mechanical strength for CO2 separation

Ceramic-carbonate dual-phase hollow fiber membranes offer good performance for CO2 separation at the temperature of 600–1000 °C but suffer from poor mechanical strength. This paper reports a new structure of a ceramic-carbonate, dual-phase hollow fiber membrane with high CO2 permeance and superior mechanical strength for CO2 separation. The hollow fiber supports of about 1.4 mm OD and 1.0 mm ID are made of Ce0.8Sm0.2O2-δ (SDC) and La2NiO4+δ (LNO) materials. The final hollow fiber membrane contains an SDC-carbonate outer layer and a SDC/LNO inner layer, forming a special double-layer structure of the membrane. The CO2 flux of the membrane is 2.3 mL min−1·cm−2 at 750 °C. In addition, the ultimate load and bending strength of the new SDC-SDC/LNO-carbonate hollow fiber membrane are, respectively, 3.6 and 1.9 times higher than that of pure single-layer SDC-carbonate hollow fiber membrane. This improvement of the mechanical strength is enabled by the unique double-layer structure of the hollow fiber membrane.