Carbon dioxide capture using an omniphobic membrane for a gas-liquid contacting process

Abstract

An omniphobic membrane has been successfully prepared to ensure high efficiency as well as long-term stability in a CO2 absorption process. This omniphobic membrane was fabricated by creating a multilevel re-entrant structure via depositing ZnO nanoparticles (NPs) on a porous glass fiber (GF) membrane through chemical bath deposition (CBD). The membrane coated with ZnO NPs was then functionalized with 1 H,1 H,2 H,2H-perfluorodecyltriethoxysilane (FAS17) and coated with a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) polymer. A variety of techniques such as capillary flow porometry (CFP), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle goniometry, atomic force microscope (AFM) and CO2 absorption trials were conducted to explore the surface structure, chemistry and performance of the membrane. The omniphobic membrane surface with a high fluorine concentration had a strong resistance to wetting by water and organic liquids (γ = 72.8–22.1 mN/m) and showed a contact angle with an amine absorbent as high as 147.8 ± 0.8°. In the CO2 absorption trials, the omniphobic membrane exhibited a stable absorption flux of 2.10 ± 0.07 mmol/m2s for 96 h. The results indicate that the omniphobic membrane outperforms hydrophobic membranes. Thus, the omniphobic membrane has shown potential for application in large-scale CO2 absorption in thermal power plants.