Biomimetic hydroxypropyl-β-cyclodextrin (Hβ-CD) / polyamide (PA) membranes for CO2 separation

Carbonic anhydrase (CA)-inspired membranes for CO 2 separation were constructed by introducing hydroxypropyl-β-cyclodextrins (Hβ-CDs) into the polyamide networks, which were formed via interfacial polymerization reactions between trimesoyl chloride and tertiary amino-containing monomers . Hydrophobic inner cavities of Hβ-CDs with the hydrophilic exterior can be used to simulate the hydrophobic pockets of CA enzymes. Hydrophilic and hydrophobic regions were constructed via introducing Hβ-CDs into membranes, while the transport of nonpolar CO 2 molecules and polar components (H 2 O and HCO 3 − ) in CO 2 hydration reactions could be enhanced. Meanwhile, tertiary amino groups in biomimetic membranes can act as the base catalysts for CO 2 hydration reactions, which were deemed as carriers for facilitated transport membranes. Biomimetic membranes containing Hβ-CDs and tertiary amino groups exhibited outstanding CO 2 permeance of 2792 GPU and CO 2 /N 2 selectivity of 171 at 0.15 MPa, showing the potentials for low-pressure CO 2 capture. Particularly, CO 2 transport mechanisms were also analyzed for biomimetic facilitated-transport membranes, which can supply new visions for developing novel membrane materials for CO 2 separation.