Coordination-reconstructed cellulose membranes for precise molecular separation

Molecular separations that purify and recovery waste solvents are essential to sustainable chemical industries. Solvent-resistant nanoporous cellulose membranes (CMs) hold great promise in organic separations, yet their pore engineering is hindered by extensive hydrogen bonding among hydroxyl groups of cellulose chains, thus restricting structural regulation for precise separations. Herein, we reported coordination-reconstructed cellulose membranes (CRCMs) by partially replacing hydrogen bonds with metal-organic coordination. Immersing CMs in alkaline cupric solution disrupts the hydrogen bonds among hydroxyl groups and establish hydroxyl-Cu 2+ linkages in cellulose networks. Altering Cu 2+ content in CRCMs enables precise tuning of pore size, generating superior permselectivity over current cellulose-based membranes. Cu 2+ coordination also enhances intrachain binding, which elevates the mechanical strength with nearly ten-fold increased swelling resistance of CRCMs, therefore harvesting pressure resistance up to 20 bar in ethanol. The optimized CRCM maintains stable permselectivity for over 2800 min and achieves solute rejection up to 99.9 % for multicomponent organic mixtures, demonstrating superior durability and adaptability for complicated organics separations. Our coordination-driven reconstruction approach may open new avenues for engineering biomass-based molecular-separation membranes.