Superhydrophobic ceramic membrane coupled with a biphasic solvent for efficient CO2 capture

An innovative strategy was proposed by integration of membrane contactor (MC) with biphasic solvent for efficient CO capture from flue gas. The accessible fly ash-based ceramic membrane (CM) underwent hydrophobic modification through silane grafting, followed by fluoroalkylsilane decoration, to prepare the superhydrophobic membrane (CSCM). The CSCM significantly improved resistance to wetting by the biphasic solvent, consisting of amine (DETA) and sulfolane (TMS). Morphological characterizations and chemical analysis revealed the notable enhancements in pore structure and hydrophobic chemical groups for the modified membrane. Predictions of wetting/bubbling behavior based on static wetting theory referred the liquid entry pressure (LEP) of CSCM increased by 20 kPa compared to pristine CM. Compared with traditional amine solvents, the biphasic solvent presented the expected phase separation. Performance experiments demonstrated that the CO capture efficiency of the biphasic solvent increased by 7%, and the electrical energy required for desorption decreased by 32%. The 60-h continuous testing and supplemental characterization of used membrane confirmed the excellent adaptability and durability of the CSCMs. This study provides a potential approach for accessing hydrophobic ceramic membranes and biphasic solvents for industrial CO capture.