CO2 capture performance of ceramic membrane with superhydrophobic modification based on deposited SiO2 particles

Membrane absorption is a promising CO2 capture technology, which is limited by the high cost of membrane materials. Coal fly ash (CFA)-based ceramic membrane as an alternative material for membrane modules can effectively reduce the preparation cost. In this study, CFA-based ceramic membrane with superhydrophobic properties is prepared by depositing SiO2 nanoparticles and grafting 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (POTS). Characters including pore size distribution, porosity and N2 flux of superhydrophobic membrane are performed. The superhydrophobic modified ceramic membrane is applied to CO2 capture experiments using ethanolamine (MEA) solution as the absorbent. The result shows that the contact angle of the modified ceramic membrane reaches 155.0°, which significantly improves the anti-wetting properties of the membrane surface. The CO2 capture experiment demonstrates a maximum capture efficiency of 97.45% and a mass transfer rate of 21.17 mol/(m2·h). In addition, the superhydrophobic modified ceramic membrane exhibits excellent thermal and chemical stability, sustaining high performance even after 8 h of continuous operation. This study provides the theoretical and empirical foundation for the application of CFA-based superhydrophobic ceramic membranes in CO2 capture.