Bio-Inspired 2D Nanochannels With Adaptive Gating for Intelligent Molecular Sieving.

Intelligent membranes with programmable permeance and precise sieving performance are in high demand for complex water treatment scenarios. Herein, a bioinspired membrane featuring intelligent adaptive 2D nanochannels with outstanding molecule sieving performance is reported. In particular, a protein-mimetic 2D nanochannel with pH-responsive characteristics is constructed by introducing sodium alginate (SA) molecular chains into GO laminates. The conformational transformation of SA chains under varying pH conditions enables adaptive regulation of the 2D channel size and selective molecular transport. The resulting GO-SA membrane possesses outstanding water permeance up to 122.67 L m-2 h-1 bar-1, along with a high sieving response factor of 50.12. Besides, it is discovered that the introduction of multivalent Ca2+ ions can stabilize the membrane structure, thereby "locking" the pH-responsive behavior. Based on this, the water treatment system is designed can not only realize the multistage separation of dye molecules, but also enable the recovery and recycling of acid and alkali. This strategy provides insights for designing intelligent membranes with gated responses.