Electric-field-induced ultrafast and selective ZIF-8 filling in graphene membrane pores for precision dye desalination

Integrating metal-organic-frameworks (MOFs) into graphene oxide (GO) membranes offers a pathway toward stable and highly selective nanofiltration, yet conventional blending or precursor-diffusion-driven in situ growth compromise structural integrity and is prohibitively slow (∼36 h). Here, we report an electric-field-driven strategy that induces electrophoretic migration of Zn 2+ and 2-methylimidazole precursors, enabling ultrafast (<60 s) synthesis of ZIF-8 within the internal pores of ethylenediamine (EDA)-crosslinked GO-based membranes intercalated by arched graphene (WG). Growth is directed preferentially into high-permeability channels, sequentially plugging dominant and subdominant pores at a rate 2160 times faster than diffusion. This selective pore filling suppresses ZIF-8 overgrowth and minimizes structural disruption, while enhancing rejection performance. The resulting membrane exhibits exceptional dye rejection of 87.11 % (MB), 99.45 % (EBT), 97.39 % (CV), 99.21 % (CR), and 99.37 % (TB), surpassing pristine GO (36.90–91.07 %) and slightly outperforming diffusion-grown counterparts. Meanwhile, the intrinsic 0.7 nm pores of ZIF-8 permit nearly complete salt permeation (rejection <2.73 %), yielding practical dye/salt selectivity >8. Amine-functionalized ZIF-8 further promotes crosslinking, imparting remarkable stability: wet/dry interlayer spacing variation <1 Å and strong resistance to acid/base exposure, hydraulic flushing, and ultrasonication. This electric-field-guided, sub-nanopore engineering strategy thus establishes a generalizable platform for precision separation membranes using diverse substrates and porous framework.