CO2 capture using superhydrophobic ceramic membrane: Preparation and performance analysis

The application of membrane absorption for CO2 capture has been limited by membrane wetting. In this paper, tubular Al2O3 ceramic membranes (marked as M1 and M2) are hydrophobically modified by sol-gel and dip-coating method and then used for CO2 capture. The surface morphology, surface composition, wettability and flux are characterized in detail. The mass transfer performance of M1 and M2 is studied at different gas and liquid Reynolds numbers. After modification, the surface contact angle can reach as high as 170.7°. The carbon capture performance of the modified M1 and M2 is significantly improved. Under laminar flow condition, CO2 mass transfer coefficient increased from the initial 1.03 × 10−4 m/s to 14.59 × 10−4 m/s, and the CO2 capture efficiency increased from the initial 28.55%–98.55%. The mass transfer resistance of ceramic membrane contactor is also analyzed. The resistance of liquid phase plays a leading role in the mass transfer performance in laminar flow state. For non-wetting membrane, membrane thickness has little effect on the mass transfer performance. In addition, it is shown that the superhydrophobic M1 and M2 exhibit excellent corrosion resistance. The research in this paper shows that superhydrophobic ceramic membrane is more suitable for CO2 capture in industrial production.