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 Ce_0.8Sm_0.2O_2-δ (SDC) and La₂NiO_4+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.