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.