Anomalous water molecular gating from atomic-scale graphene capillaries for precise and ultrafast molecular sieving

Addressing the global clean water crisis necessitates membranes capable of both effective ion sieving and high water flux. This study introduces anomalous water molecular gating using nanofiltration membranes comprised of 6 Å graphene capillaries, fabricated via π–π restacking of graphitic microstructures. The membrane effectively sieves ions, reducing osmosis-driven ion diffusion to negligible levels (~10⁻¹⁰⁺ mol m⁻² h⁻¹), while maintaining ultrafast water flux (45.4 L m⁻² h⁻¹) controlled by hydrostatic pressure. This is attributed to graphene nanoconfinement, where crystal-like water facilitates high-speed, diffusion-free transport analogous to Grotthus conduction. This approach establishes a liquid-solid-liquid, phase-changing molecular transport for precise and ultrafast molecular sieving.

Qian Zhang, Bo Gao, Ling Zhang, Xiaopeng Liu, Jixiang Cui, Yijun Cao, Hongbo Zeng, Qun Xu, Xinwei Cui, Lei Jiang