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Two-dimensional (2D) metal-organic framework (MOF) membranes have garnered significant attention for high throughput and precise molecular/ionic sieving. However, the delamination of lamellar nanosheet structure challenges the continuous separation under the intense fluid shear in real hydraulic pressure and cross-flow operation. Here we present a highly durable nickel-derived metal-organic framework (Ni-MOF) lamellar membrane stabilized by a polymer network of gallic acid (GA) and polyethyleneimine (PEI) for efficient ions/molecules separation. The crosslinked network construction reinforced the nanosheets interaction and contributed to the interlayer structure integrity, thus maintaining the Ni-MOF membrane a stable water permeance and nano/sub-nanometer selectivity (permeance >80 L m−2 h−1 bar−1, S dye/NaCl >100) for 170 h under cross-flow, superior to most lamellar membranes under dead-end filtration. Moreover, the Ni-MOF membrane could withstand multiple bending and violent ultrasonic treatment (190 W). The lamellar crosslinking reinforced strategy is applicable to other lamellar MOF membranes, which offers a forward-looking strategy to tackle 2D membrane stability and facilitate practical applications for robust separation. [Display omitted] • Lamellar crosslinking reinforces 2D MOF membranes. • The membrane shows high molecules/ions sieving properties. • The membrane is stable against shearing, bending and ultrasonication. • The membrane achieves robust permeance/selectivity for 170h. [ABSTRACT FROM AUTHOR]

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]

[Display omitted] • The anionic SCOF was synthesized by interfacial Schiff reaction as an interlayer. • SCOF interlayer enhanced the negative charges of PA membranes. • SCOF/PA membrane showed outstanding NaCl/Na 2 SO 4 selectivity and ions sieving. • SCOF/PA membrane exhibited pressure-resistance and operational stability. Ions sieving is significant but challengeable for seawater desalination, industrial water treatment and salts recovery. Traditional nanofiltration (NF) membranes suffer from undesirable ion selectivity and permeance due to uncontrolled aromatic polyamide (PA) nanofilm. Herein, we first reported an anionic covalent organic framework (TpPa-SO 3 Na) with abundant sulfonic acid groups as a mediating interlayer to fabricate PA composite membrane. The uniform and negatively charged TpPa-SO 3 Na spherical nanoparticles were in situ soldering on nylon substrate by liquid–liquid interfacial Schiff reaction. The TpPa-SO 3 Na interlayer assisted in creating a defect-free PA nanofilm through mediating the diffusion–reaction process of amine monomers. According to enhanced Donnan effect, the composite polyamide nanofiltration membrane showed an outstanding salt rejection ratio (Na 2 SO 4 , 99.6%), high single salt selectivity (NaCl/Na 2 SO 4 , 178.5) and mono/divalent anion selectivity (Cl−/SO 4 2−, 312.6), superior to most reported NF membranes. This work shed light on strategies to synthesize emerging covalent organic framework materials and to effectively construct NF composite membranes with excellent solute retention and ions sieving capabilities. [ABSTRACT FROM AUTHOR]