Fabrication of novel Janus hollow fiber membrane by Co-extrusion and grafting for enhanced CO2 removal through microbubbles

In this study, an innovative strategy of fabricating Janus hollow fiber membrane to produce microbubbles for enhancing CO 2 removal was proposed. The polyvinylidene difluoride (PVDF) hollow fiber membrane was prepared using two different hydrophilic dopes followed by modification with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS). The contact angle of the Janus hollow fiber membrane was 37° for the outer layer and 122° for the inner layer. Attenuated total reflectance Fourier transform infrared spectrometer (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) were employed to verify the grafting of FAS onto the inner layer of membrane. The unique morphology showing a progressive transition from sponge-like to finger-like pores, extending from the inner to the outer layer, was examined using a scanning electron microscope (SEM); this morphology helped reduce mass transfer resistance. Microbubbles were produced by the prepared Janus hollow fiber membrane at high and consistent fluxes. The CO 2 mass transfer flux reached 5.0 × 10⁻³mol m⁻ 2  s⁻ 1 under the gas-liquid pressure difference of 0.10 MPa. The average size of microbubbles was 75 μm and the CO 2 removal rate was nearly 100 % in CO 2 removal experiments. The Janus hollow fiber membrane developed in this study exhibited good aeration property and application potential in post-combustion CO 2 capture.