Covalent triazine frameworks membrane with highly ordered skeleton nanopores for robust and precise molecule/ion separation.

Two dimensional covalent triazine frameworks (2D-CTF) with controlled pore size and stable structure are a new class of 2D building blocks for constructing separation membrane materials. In this work, we synthesize few-layer 2D-CTF-1 nanosheets with high crystallinity and excellent solvent dispersion using a micro-interface method. The as-prepared 2D-CTF-1 membrane via filtration assembly of few-layer 2D-CTF-1 nanosheets exhibits superior permeability due to its ultralow solvent-interface interaction and the abundant in-plane pores, with a water permeance of 141.5 L m−2 h−1 at 1 bar. The skeleton-pores are proved to be the main transfer channels on 2D-CTF-1 membrane, which are stable and nondeformable by external pressure. Size screening based on the cut-off of skeleton-pore (1.39 nm) is also demonstrated, which enables 2D-CTF-1 membrane a huge application potential in precise molecule/ion sieving. Besides, a stable layered structure in aqueous environment renders 2D-CTF-1 membrane with outstanding separation performance in the long-term running, continuously keeping high permeability and selectively. Thus, this work shows a promising application of 2D-CTF-1 as building blocks for 2D membrane construction in the separation field. 2D-CTF-1 membrane with highly ordered skeleton nanopores (intrasheet pathways) as the main transfer channels exhibits robust and precise molecule/ion separation performance. Image 1 • Covalent triazine frameworks membranes were fabricated for precise separation. • The abundant skeleton-pores dominated the mass transfer of 2D-CTF-1 membrane. • Precise molecule sieving was achieved via the skeleton-pores at nano-scale. • 2D-CTF-1 membrane showed stable layered structure and separation performance. [ABSTRACT FROM AUTHOR]