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Nanofiltration membrane technology for antibiotic desalination in fermentation broth represents a low-energy and high-purity approach. However, it is constrained by the low perm-selectivity and susceptibility to membrane fouling. Here, we develop a novel zwitterionic nanofiltration membrane by incorporating an N-Oxide directly connected zwitterion N,N-bis(3-aminopropyl)methylamine N-oxide (DNMAO) into the nascent polyamide layer via interfacial polymerization. The N-Oxide derived zwitterion created a looser crosslinking network in addition to the trimesoyl chloride-piperazine (TMC-PIP) network, which was supported by Stokes radius related with molecular weight cut-off measurement, and Brunauer-Emmett-Teller Ar adsorption isotherms. Moreover, the directly connected groups (N+-O-) without spacers endow excellent hydration ability and mitigate membrane fouling. The optimized membrane exhibits a water flux of 114.9 L m−2 h−1 and exceptional anti-fouling performance with a flux recovery ratio as high as about 96.4 %. Furthermore, the salt/antibiotic separation factor maintained at 41.1 when continuously filtrating NaCl/erythromycin (ERY) mixed solution for 7 h, which showed a great potential in antibiotic purification. [Display omitted] • N-Oxide connected zwitterionic DNMAO for surface modification of the TFC membrane. • The membrane shows high water permeance and antibiotics/salt selectivity. • The membrane improves both antifouling and antibacterial properties. • The membrane achieves robust permeance/selectivity under continuous operation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The unitary and binary pore CTF membranes were prepared by interfacial polymerization. • Ultrafast molecular-level perm-selectivity was finely tuned by the structural pore size. • The OSN membrane fouling could be alleviated via photocatalysis. • The membrane achieves multiple-cycle "operation-fouling-in situ cleaning-operation" stability for OSN process. Covalent organic frameworks (COF) membranes are considered as promising candidates for organic solvent nanofiltration (OSN) due to their well-defined porosity, high perm-selectivity, and exceptional resistance to solvents. However, irreversible membrane fouling caused by filter cake layers or pore clogging challenges the robust separation over long-term operation especially for well-known COF membranes. Here, we present novel ultrafast covalent triazine frameworks (CTF) membranes with retrievable separation performances for OSN processes. CTF-1 membrane with unitary nanopore and CTF-m membrane with binary nanopore are fabricated via an air-organic solvent interfacial polymerization technique for comparison, which demonstrates molecular-level selectivity (MWCO, ∼320 Da for CTF-1 and ∼ 625 Da for CTF-m) and ultrafast permeability for polar organic solvents. Moreover, the heterogeneous skeleton nanopores structure of CTF-m membranes facilitates efficient separation of photogenerated carriers, thus resulting in retrievable permselectivity. This work offers an efficient strategy via Donor-Acceptor structure modulation to tackle OSN membrane fouling, paving the way for applications of framework membranes. [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]