Developing robust omniphobic ceramic membrane for energy-efficient carbon capture using biphasic solvent

Energy-efficient CO 2 membrane absorption enhanced by biphasic solvent was explored in this study, in which a novel omniphobic ceramic membrane was primarily developed to overcome the highly occurred pore wetting risk of conventional hydrophobic organic membrane by biphasic solvent with a low surface tension. The omniphobic ceramic membrane was fabricated by constructing the rough titanium dioxide (TiO 2 ) nanorods on the pristine ceramic membrane surface via a hydrothermal method, followed by fluorination, which effectively enhanced the solvent repellency of membrane. Compared to the pristine membrane, the hierarchical omniphobic membrane showed a higher surface roughness due to the formed uniform flower-like nanostructures. The fluorination treatment created the low-surface-energy membrane with the contact angles of 166.47±4.25° and 139.06±3.30° for water and a typical biphasic solvent with ∼35 mN/m surface tension (i.e., 20 wt.% triethylenetetramine+60 wt.% sulfolane balanced by deionized water) respectively, causing a better stability of membrane without pore wetting during the 60-hour CO 2 absorption operation. When adopting the omniphobic ceramic membrane as the barrier between the biphasic solvent and CO 2 , the phase separation behavior occurred successfully outside the membrane contactor, and ∼88% of captured CO 2 was rapidly enriched in the concentrated phase of biphasic solvent that accounted for only 55% of the total solvent volume, implying the feasibility of omniphobic ceramic membrane in the carbon capture process using biphasic solvent. This study might provide a scalable strategy to fabricate the omniphobic ceramic membrane adapted for biphasic-solvent-based CO 2 membrane absorption.