Jiangtao Liu

Separation and purification of active pharmaceutical ingredients (APIs) are essential in the pharmaceutical industry. The successful implementation of polyamide (PA)‐based nanofiltration (NF) membranes for solute‐solute and solute‐solvent separations in the antibiotic pharmaceutical industry requires precise sieving capacity across various solutes and solvents. Nevertheless, the rapid and stochastic interfacial polymerization (IP) reaction generates non‐uniform pores. We report a lysozyme‐regulated IP (LIP) strategy to promote the accumulation and diffusion of amine monomers, thereby forming a PA‐selective layer with a high level of pore size uniformity. The PA membranes prepared by LIP feature transcendent selectivity coefficients for Na ₂ SO ₄ /NaCl (∼176) and antibiotic/NaCl (∼98), accompanied by an excellent pure water permeance of 17.2 L m ⁻² h ⁻¹ bar ⁻¹ . The membrane also exhibits a high methanol permeance of 20.0 L m ⁻² h ⁻¹ bar ⁻¹ and achieves a 5.8‐fold increase in APIs concentration during 12‐h operation. These outstanding performance metrics of the PA membrane are superior to those of state‐of‐the‐art NF membranes. Notably, the fabrication is scaled up to a large area (1.0 m × 0.3 m), signifying its practical viability for APIs separation. This work paves a new way to develop advanced functional membranes for effectively purifying pharmaceuticals and recycling solvents towards sustainable high‐value separations.

Membrane separation technology represents a promising and effective alternative to traditional energy-intensive gas separation technologies. However, most commercial membranes have low permeability and moderate selectivity, which limits their ability to meet the stringent gas purity requirements for hydrogen purification and natural gas upgrading. In this study, Matrimid, a widely used commercial polymer, was selected as the matrix material. Cucurbituril (CB) with selective cavity was incorporated into Matrimid as short-path gas transport channels. This modification increased the gas transport pathways and enhanced the connectivity of gas transmission networks within the membrane structure. The H ₂ permeability of Matrimid-CB-5% membrane decreased from 113 to 74 Barrer, while the H ₂ /CH ₄ selectivity increased from 169 to 743 during 600-day aging. Notably, the membranes achieved separation efficiencies that surpassed the latest upper bound line for CO ₂ /N ₂ and CO ₂ /CH ₄ separations. These results indicate a substantial improvement over widely used commercial materials such as Matrimid, cellulose acetate, polysulfone, and other mixed matrix membranes.

While membrane technology represents a promising approach for postcombustion carbon capture, its widespread application remains hindered by the permeability–selectivity trade-off and operational instability. Porous organic cages (POCs), as soluble discrete molecules, enable molecular-level mixing with polymer matrices, substantially minimizing interfacial defects and thereby enhancing gas selectivity. Herein, we present a molecular engineering strategy by integrating 2,5-dihydroxyterephthalaldehyde-tris(2-aminoethyl)amine cage (2,5-DHA-TAEA cage) into the polymer of intrinsic microporosity-1 (PIM-1), utilizing molecular cages that feature a precise 3.6 Å window─effectively intermediate between CO₂ and N₂ kinetic diameters. Combined with surface hydroxyl polar sites, this unique architecture establishes a synergistic “confinement sieving-polarity adsorption” mechanism. This dual functionality empowers the resulting composite membrane to achieve exceptional performance, delivering CO₂ permeability of 4690.8 Barrer and CO₂/N₂ selectivity of 35.6 under single-gas conditions, surpassing the 2019 Robeson upper bound. Significantly, under simulated flue gas conditions (CO₂/N₂: 50/50 v/v), the optimized PIM-POC-5 wt % exhibited 115% and 145% enhancements in CO₂ permeability and CO₂/N₂ selectivity, respectively, compared to the pure PIM-1. Furthermore, stability was demonstrated under high pressure (20 bar), elevated temperature (100 °C), and 120-day aging. This work provides a versatile strategy for designing stable, high-performance separation membranes for sustainable carbon capture.

Mixed-matrix membranes (MMMs) with high chain packing density by incorporating soluble macrocycle compounds represent a promising class of materials for gas separation. However, achieving the ultra-high selectivity (He/CH ₄ > 1000) for helium extraction from natural gas with ultra-low helium content remains a formidable challenge, especially for Matrimid membranes, which are commercially available but exhibit relatively low permeability and moderate selectivity. Herein, the cyclic Cyclen with specific intra-ring dimensions was incorporated into Matrimid as a pore-structure modifier to enhance the He/CH ₄ selectivity. The strong hydrogen bonding interactions between Cyclen and Matrimid chains induced a denser chain stacking and modulation of the interchain gap structures, which enables rapid mass transfer of small He gas molecules while hindering the diffusion of large CH ₄ gas molecules across the membrane, thereby significantly enhanced He/CH ₄ molecular sieving capacity. Molecular dynamics simulations indicate that the MMMs prepared using Cyclen as a filler exhibited tunable microporous and more efficient He transport channels. Notably, the He/CH ₄ selectivity reached up to an impressive value of 6788 after physical aging for 110 days, which outperformed almost all reported polymer-based membranes and was even comparable to that of some advanced carbon molecular sieve membranes.

The development of conjugated microporous polymers (CMPs) with extended π ‐conjugation has positioned them as promising candidates for advanced gas separation membranes. Realizing their superior performance hinges on the rational design of their porous frameworks. Herein, we report a novel strategy to create tunable localized electric fields within CMPs by incorporating triazine rings at varied molecular positions, thereby achieving highly efficient CO ₂ separation in Pebax‐based mixed matrix membranes (MMMs). As designed, the fine‐tuning of the triazine units enables the construction of an optimized donor‐ π ‐acceptor (D‐ π ‐A) electronic structure in the CMP‐PT framework. This tailored structure enhances intermolecular interactions, confers a larger dipole moment, improves coordination capability, and ultimately optimizes the microporous environment of the resultant MMM. Compared to the pristine Pebax membrane, the optimal Pebax‐CMP‐PT‐1% MMM exhibits a remarkable 83.4% enhancement in CO ₂ permeability and a CO ₂ /N ₂ selectivity of 167.31 at 20 bar, surpassing the 2019 Robeson upper bound. This work provides a valuable strategy for the development of next‐generation high‐performance CO ₂ separation membranes.

Highly permeable and selective biomimetic membranes that can feel and recognize valuable ion species have attracted enthusiastic interest due to their analogous behavior with biological ion channels and potential applications in rigorous ion sieving. However, designing and developing single-species selective membranes that can isolate monovalent cations such as K⁺/Na⁺ remains a tremendous challenge due to the sub-nanometer ion size, as well as the angstrom-sized difference. Considering the non-homogeneous heterostructure of KcsA channels and -COOH groups generally showing lower K⁺ affinity, we propose the 1D MOF (rich in -COOH groups)-in-2D COF concept, aiming to enhance K⁺/Na⁺ separation through strategic construction of heterogeneous ion transport channels, therefore narrowing the pore size of pristine COF membrane, and weakening the K⁺-channel wall interactions. Concretely, by interlocking and in situ immobilized growth, the pristine COF membrane is capable of capturing MOF ligands and metal ions in sequence to form 1D MOF-in-2D COF hetero-structured composite membranes. Benefiting from the molecular-level interlinked hybridization of covalent and metal organic hetero-frameworks induced by the coordination interaction between the -NH groups in COFs and the Cu centers from MOFs, the composite membrane enables rapid diffusion of K⁺ in confined heterogeneous channels, thus leading to unprecedented cation sieving performance with K⁺/Na⁺ selectivity approaching 10² and K⁺/Mg²⁺ selectivity exceeding 10³. This membrane design concept exploits a viable avenue for developing single-species selective biomimetic membranes to achieve ultrahigh separation performance.

Tailorable membrane surface architectures are crucial for efficient and precise separation. The nanoemulsion regulation strategy, an emerging technique for constructing nanostructured membranes with tunable architectures, has been scarcely explored for the fabrication of covalent organic framework (COF) membranes. In this work, inspired by the vesicle storage, transport, and release mechanism in human cells and the natural self-assembly of emulsions at interfaces, we proposed a nanoemulsion-directed interfacial polymerization (NDIP) strategy to precisely construct COF membranes with tunable Turing patterns. The introduction of these Turing structures leads to COF membranes with fewer defects and an enlarged surface area, attributable to the nanoemulsion templating effect and the controlled monomer transport mechanism. Short-range van der Waals forces and electrostatic interactions between the nanoemulsions and monomers were elucidated through molecular dynamics simulations and experimental results. Moreover, we systematically explored the effects of variable nanoemulsification space, different internal microenvironments, and emulsifier chain length on membrane separation performance. The designed Turing COF membranes exhibit excellent antibiotic separation ability with a molecular weight cutoff of 289 g/mol and ultrahigh antibiotic/salt selectivity (124.1 for TC/NaCl). This study provides a new design perspective for patterned regulation in COF membranes and highlights the potential of emulsion-guided strategies for advanced molecular separations.