Stable molecular-bridged graphene oxide membrane with bioinspired hydrophilic water inlets for ultrafast molecular separation

Despite their considerable promise in water treatment, two-dimensional graphene oxide (GO) membranes are still hindered by inadequate structural stability due to weak interlayer interactions and structural defects, along with low permeability due to limited surface water inlets. Here, inspired by the leaf structure of Tillandsia, a stable and ultrapermeable GO-based membrane with Wenzel model hydrophilic surface and robust interior nanochannels was fabricated through interlayer molecular bridge and in-situ growth of covalent organic framework (COF, TP-TTTA) nanocrystals. The incorporation of amine monomer (4,4′,4″-(1,3, 5-triazine-2,4,6-triyl)trianiline, TTTA) molecular bridges for covalent crosslinking of GO nanosheets effectively stabilized the membrane framework. The obtained GO@TP-TTTA membrane resisted structural disassembly under prolonged acidic/alkaline immersion and high-pressure conditions. The in-situ growth of TP-TTTA COF led to a rough membrane surface with numerous selective and hydrophilic inlets. Thus, the water permeability of the obtained GO@TP-TTTA membrane could reach up to 246.9 L·m −2 ·h −1 ·bar −1 –2.6 times larger than that of pristine GO membrane–along with a retained 98.3 % rejection rate for bright blue G (BBG), successfully overcoming the common permeability-selectivity trade-off. Moreover, the resultant membrane demonstrated superior anti-fouling properties than the pure GO membrane. This molecular-scale structural design offers a novel approach for high-performance GO-based membranes, with promising applications in wastewater treatment. • Molecular bridge covalently crosslinks GO nanosheets, enhancing membrane stability. • In-situ grown TP-TTTA COFs form robust interior nanochannels in GO membranes. • Wenzel hydrophilic surface structure boosts water permeability significantly. • COF@TP-TTTA membrane stays stable under acid, alkali, and high-pressure conditions. • Membrane achieves ultrahigh water flux and dye rejection, breaking conventional trade-offs.