Bioinspired artificial water channels-COF membranes for enhanced desalination of brackish water

Artificial water channels (AWCs) are discovered as the synthetic counterparts of biological aquaporins to construct a variety of bioinspired membranes. However, fabricating AWCs-based membranes featuring high-density channels and uniform incorporation proves a great challenge because discrete AWCs superstructures often possess poor film-forming capability. For the first time, we demonstrate that the colloid-assisted self-assembly of AWCs in COF membranes achieves Å-scale separations with high water-to-salt permselectivity in desalination of brackish water. Compared with the pristine TpPa2 membrane, the bioinspired HC6-TpPa2 membranes manifest a permeance of 17.8–27.3 L m −2  h −1 bar −1 and a salt rejection of 95.6 % (NaCl), 96.3 % (CaCl 2 ), 98.1 % (MgCl 2 ), 98.8 % (MgSO 4 ) and 99.6 % (Na 2 SO 4 ). Surprisingly, the HC6-TpPa2 membranes demonstrate significantly enhanced anti-swelling and anti-fouling abilities as well as high stability with almost no performance decline after 14-day filtration, surpassing ever-reported COF membranes. The AWCs-COF membranes for enhanced desalination open a novel avenue to fabricating bioinspired membranes for advanced separations.