The separation of ethylene (C2H4) from ethane (C2H6) is a critical yet energy-intensive process in the chemical industry, demanding energy-efficient and cost-effective solutions. Here, we report a Li+-exchanged silicoaluminophosphate RHO zeolite (Li-SAPO-RHO) with unprecedented selectivity for C2H4 over C2H6. This exceptional performance is attributed to the synergy between H+ and Li+ ions strategically positioned at the flexible eight-membered ring (8MR) gates of the zeolite. These ions effectively modulate the transport barriers for C2H4 and C2H6, significantly enhancing separation efficiency. Li-SAPO-RHO exhibits an Ideal Adsorbed Solution Theory selectivity exceeding 20,000 and enables the production of polymer-grade C2H4 (>99.9%) from refinery dry gas, with a productivity of up to 238.6 mmol/L. This performance surpasses that of all existing zeolite and metal-organic framework-based benchmark adsorbents. The H+-Li+ synergistic gating effect has been investigated using advanced characterization techniques, such as electron diffraction and neutron powder diffraction, along with ab initio molecular dynamics simulations. In addition to its exceptional selectivity and productivity, Li-SAPO-RHO offers advantages of low-cost synthesis, ultrahigh stability, and excellent cyclic performance, making it a highly promising candidate for industrial-scale light olefin separations.

Efficient separation of propylene from propane is a critical yet challenging industrial process. While rigid molecular sieves offer ideal selectivity, their narrow nanopores inherently constrain adsorption capacity and diffusion kinetics due to compromised thermodynamic-kinetic trade-offs. To address this, we report ZSTU-10, a molecular sieve constructed via structure-directing agents. Uniquely, ZSTU-10 features localized sieving gates for selective guest admission, expansive diffusion channels for rapid transport, and central pore cavities for high-capacity storage. This gate-channel-cavity architecture enables the precise exclusion of propane while facilitating the dense packing and fast diffusion of propylene, achieving simultaneous thermodynamic-kinetics optimization in molecular sieving. Static adsorption experiments demonstrate an exceptional propylene uptake (97.7 cm3 cm-3) at 298 K and 1 bar. Time-dependent uptake kinetics revealed a propylene diffusion coefficient (4.29 × 10-9 cm2 s-1) in ZSTU-10 surpassing benchmarks by two orders of magnitude. Dynamic breakthrough experiments demonstrate that ZSTU-10 produces high-purity propylene (99.1%) with a productivity of 37.5 L kg-1 in a single adsorption-desorption cycle.

Morphology control is a powerful approach to tailor the properties of metal-organic frameworks (MOFs) for separation, catalysis, sensing, and photonics applications. However, previous efforts have primarily focused on microporous systems with pore sizes beyond typical gas dimension thresholds (>0.5 nm); the structural integrity of ultramicroporous MOFs under morphology modulation, particularly the risk of pore destruction or blockage, and their implications for molecular sieving remain insufficiently understood. Herein, we report the morphology control of an ultramicroporous MOF, Co-gallate (3.69 Å), using different kinds of surfactants. By employing cationic (cetyltrimethylammonium bromide, CTAB), nonionic (polyvinylpyrrolidone, PVP), and anionic (sodium dodecylbenzenesulfonate, SDBS) surfactants, diverse morphologies including elongated hexagonal bipyramids, microspheres, and hexagonal nanoplates are obtained. CTAB and PVP direct crystal growth via nucleation-accumulation and template-guided assembly, respectively, but both disrupt the sieving pore channels of Co-gallate due to incomplete coordination and residual surfactant blockage. Whereas SDBS micelles serve as dynamic soft templates that guide anisotropic nanoplate formation without disrupting the intrinsic sieving channels. The prepared nanoplate maintains high C2H4/C2H6 and C3H6/C3H8 sieving separation selectivity while accelerating gas adsorption kinetics due to the high aspect ratio, providing a feasible strategy to couple morphology control with preserved ultramicroporosity.

A bioinspired Cu-Fe Prussian blue analogue (PBA) functionalized PTFE membrane (Cu-Fe PBAs@M) is developed for ultra-trace cesium (Cs+) removal, achieving over 99% rejection at 50 ppb concentration under cross-flow filtration. Structural and chemical characterizations confirm uniform incorporation of Cu-Fe PBAs with a tunable Cu: Fe ratio that optimizing adsorption kinetics and membrane permeability. The membrane demonstrates an equilibrium adsorption capacity of similar to 42 mg/m(2) at trace Cs (+) levels and maintains >97.5% removal across pH 5-10. Competitive ion studies reveal selective Cs+ capture despite 200-fold excess of common cations, supported by density functional theory showing adsorption energies favoring Cs+ (-5.74 eV). Regeneration via mild acid or water elution sustains removal efficiency above 98% over multiple cycles with negligible metal leaching. Performance validation in real river water and hypersaline brines confirms operational robustness and scalability. This work establishes a scalable membrane platform for selective, high-efficiency radionuclide remediation and resource recovery from complex aqueous environments.

The synthesis of imine-linked covalent organic frameworks (COF) has traditionally relied on harsh solvothermal methods, where the use of toxic organic solvents imposes a significant environmental burden and severely impedes the scalable production of COF. Thus, developing a greener and more facile synthetic approach has emerged as a critical challenge of great significance. Herein, we report a feasible solid-state “AcOH-steam-assisted synthesis” strategy, enabling the successful preparation of three imine-linked COF (SAC-TAPB-DMTP, SAC-TAPB-SHTA, and SAC-TAPB-BTCA) with high crystallinity and BET surface areas within a significantly shortened reaction time. Through tuning the pore size of these imine-linked COF, SAC-TAPB-BTCA in particular exhibits outstanding performance for CH4 purification from ternary CH4/C2H6/C3H8 mixtures, as clearly validated by gas sorption isotherms and breakthrough experiments. Computationally simulations determine the thermodynamic binding sites for each paraffin molecule, and the corresponding host-paraffin interactions are revealed using Hirshfeld surface analysis. This study enriches the synthetic strategies for imine-linked COF, offering broader opportunities in various applications.

The performance of metal-organic frameworks (MOFs) is profoundly shaped by the distribution and diffusion of confined water, yet condensable molecules such as H2O remain less explored than noncondensable gases. Here, we combine molecular dynamics and Monte Carlo simulations with infrared spectroscopy and water adsorption experiments to reveal nonmonotonic, loading-dependent water diffusion behaviors in four representative MOFs: ZIF-90, ZIF-8, ZIF-67, and UiO-66. At low to medium loadings, water sequentially occupies cages to form clusters, with diffusivity decreasing as water loading increases. At high loadings, they organize into an extended network, leading to rapid water diffusion. Such counterintuitive transitions contrast sharply with the behavior of noncondensable molecules and strongly correlate with the enthalpy of vaporization across various water models, emphasizing the dominant role of water-water interactions in governing diffusion in MOFs. Our findings clarify the unique loading-dependent diffusion behavior of condensable molecules in MOFs and guide the rational design of high-performance MOF-based materials.

ABSTRACT The development of novel covalent organic frameworks (COFs) represents a crucial research hotspot and frontier in contemporary materials science, offering immense potential for advancing applications in catalysis and separation. However, severe restrictions in conventional solvothermal synthesis, including high reaction energy barriers, long reaction times, and stringent experimental conditions, constrain the potential for uncovering novel structures, particularly challenging fluorinated covalent organic frameworks (FCOFs). Consequently, we propose an innovative steam‐assisted conversion (SAC) strategy to address this critical bottleneck and fully unlock the application potential of FCOFs. A series of fluorinated COFs (4F‐LZU‐1‐COF, 4F‐SHTA‐Pa‐COF, and 4F‐DHTA‐Pa‐COF) have been successfully synthesized. Real‐space imaging of FCOFs using ultralow‐dose high‐resolution transmission electron microscopy confirmed their superior crystallinity. Notably, our SAC strategy offers a remarkably mild, rapid, and environmentally friendly synthetic route, which effectively addressing the limitations of the traditional solvothermal approach. These materials demonstrate efficient Xe/Kr separation performance due to the presence of the fluorine sites. Most importantly, FCOFs can tolerate high‐intensity γ‐irradiation, making them outstanding candidates for the treatment of radioactive effluent gases. These intriguing findings highlight our SAC strategy as a viable and scalable route for the synthesis of robust FCOFs, broadening the scope of COF fabrication, and opens new avenues for their applications.

Controlling the crystal orientation of metal-organic framework (MOF) membranes introduces a new dimension to chemical separations, as the alignment of anisotropic pore channels dictates the membrane's separation performance. Here, we demonstrate that the gas separation behavior of the MOF membrane can be reversibly switched by tailoring their crystal orientation. Through a solvent-induced liquid-vapor deposition (LVD) strategy, we realize the direct, seed-free growth of a highly (112)-oriented ultrathin KAUST-7 membrane. For comparison, a (001)-pore-aligned KAUST-7 membrane is prepared via secondary growth. In contrast to conventional physical size-preferred orientations, variation in channel alignment here reconfigures the exposure of fluorine-rich NbOF52- adsorption centers toward CO2, establishing a chemical-preferred orientation that induces transition between entropy and enthalpy dominant molecular transport. Consequently, gas permeation tests reveal that the (112)-oriented KAUST-7 membrane exhibits an H2/CO2 selectivity of 52.7, whereas the (001)-pore-aligned KAUST-7 membrane shows a reversed CO2/H2 selectivity of 4.7. This marked contrast underscores that the separation properties of MOF membranes are not solely material-dependent but can be deliberately switched and optimized through crystal orientation engineering, offering a versatile design strategy for adaptive separation membranes.

The preferential identification of inert ethane molecules and the corresponding pore-filling mechanism are fundamentally challenging. Although flexible metal-organic frameworks are considered promising candidates to enhance ethane selectivity, their gate-opening pressures for ethane and ethylene are usually similar, which limits further improvement in their separation performance. Here, we report a flexible-robust metal-organic framework, TYUT-18, whose binary pore system combined with the flexible deformation of the framework produces significantly different gate-opening pressures for ethane (0.18 bar) and ethylene (0.48 bar) at 298 K, effectively reducing competitive adsorption in the same pore and improving overall separation efficiency, and achieves the purification of ultra-high purity ethylene (99.995%) with a separation productivity of 15.7 L kg-1. More importantly, we have systematically elucidated the dynamic filling behavior of ethane molecules in the flexible-robust framework system, a process of preferentially occupying the large pore cavities then filling into the small ones was uncovered using a combination of extensive single-crystal X-ray diffraction studies and density functional theory calculations. The evolution of this sequential guest-filling mechanism demonstrated the merit of binary pore networks for challenging gas separation tasks and thereby offers valuable insights for the design of highly selective separation materials.

The low-cost C3H8/C3H6/C3H4 separation for high-grade C3H6 is of paramount importance but extremely difficult in the chemical industry. Here we report an economic strategy of functionalizing Zr-based metal-organic frameworks (MOFs) with amino acids for one-step C3H6 purification from ternary C3 mixtures. The resulting UiO-67-AA exhibits exceptionally high C3H8 and C3H4 uptakes and benchmark selectivities for C3H8/C3H6 and C3H4/C3H6 separations, rivaling reported ternary C3 separating MOFs. Breakthrough experiments confirm its excellent performance in producing high-purity C3H6 in one step. Crucially, the estimated over 2250 times the cost reduction among reported C3H8/C3H4-selective MOFs makes UiO-67-AA an ideal candidate for industrial C3H6 purification. In situ infrared spectroscopy, in situ neutron powder diffraction, and theoretical calculations indicate that amino acids offer selective binding to dually strengthen both C3H8 and C3H4 affinity over that of C3H6, with the amino group dictating the supramolecular interactions. Systematic evaluation across UiO-67 with diverse nitrogen moieties establishes a monotonic relationship between the separation performance and the specific nitrogen electronegativity, providing an element‑specific and quantitative electronegativity-driven design rule for next-generation MOF adsorbents for industrial olefin purification.

High-purity oxygen (O2) is vital for advanced applications in medicine, aerospace, and electronics, yet its sustainable production remains challenging. Pressure-swing adsorption (PSA) offers an energy-efficient alternative to cryogenic distillation, aligning with carbon-neutral objectives. However, achieving O2 purity above 99.99% is hampered by the removal of trace argon (Ar), whose kinetic diameter and polarizability are nearly identical to those of O2. Herein, we introduce a Ligand-Folding Modulation Strategy to tailor contractible ultra-micropores in Ni(II)-based metal-organic frameworks (MOFs), enabling precise Ar/O2 discrimination. Replacing rigid dicarboxylate linkers with a flexible, foldable analogue (trans-1,4-cyclohexanedicarboxylic acid, H2CDC) induces a zigzag pore contraction, narrowing the aperture from 7.5 Å to 5.0 Å. The resulting framework, Ni-TED-CDC (TED = 1,4-diazabicyclo[2.2.2]octane), exhibits an Ar uptake of 8.45 cm3/g at 298 K and 1 bar—49% higher than its large-pore analogue—and an Ar/O2 selectivity of 1.47, placing it at the forefront of O2 purification adsorbents. Breakthrough experiments confirm its capability to deliver ultra-high-purity O2 (>99.99%), highlighting its practical potential for PSA applications. Molecular simulations reveal that ligand foldability drives a confined, square-shaped pore geometry that optimally complements spherical Ar atoms, enhancing van der Waals interactions while excluding linear O2 molecules. This work establishes ligand-folding modulation as a versatile pore-engineering strategy for constructing responsive adsorption environments, providing a general design principle for inert-gas recognition and paving the way toward low-carbon, high-efficiency O2 purification technologies.

Ethylene (C2H4) is one of the most important feedstocks in the petrochemical industry. However, industrial ethylene streams often contain trace amounts of carbon dioxide (CO2) and acetylene (C2H2), making the one-step purification of C2H4 from ternary CO2/C2H2/C2H4 mixtures a highly challenging separation task. Herein, we report an ultramicroporous metal–organic framework, Zn-BTEC-TRZ. Its ultramicroporous pore size is well matched to CO2 and C2H2 molecules, providing confined adsorption environments that promote their preferential uptake. Zn-BTEC-TRZ exhibits high adsorption capacities for CO2 and C2H2 at low pressures. At 298 K and 0.1 bar, the volumetric uptakes of CO2 and C2H2 reach 42.0 and 42.8 cm3 cm−3, respectively, whereas the uptake of C2H4 is only 2.9 cm3 cm−3. The pronounced adsorption disparity leads to exceptionally high CO2/C2H4 and C2H2/C2H4 selectivities, surpassing those of many previously reported MOF adsorbents. Moreover, Zn-BTEC-TRZ demonstrates excellent water and air stability, maintaining its structural integrity and adsorption performance after prolonged exposure to ambient conditions. Benefiting from the use of low-cost and readily available ligands, Zn-BTEC-TRZ can be synthesized on a gram scale, highlighting its potential for long-term operation and practical industrial applications.

Adsorption in nanoporous materials is pivotal for addressing global challenges in gas storage, separation, sensing, catalysis, and atmospheric water harvesting. Consequently, molecular simulations are essential for understanding adsorption mechanisms and accelerating material discovery. Key thermodynamic descriptors, such as adsorption isotherms, density distributions, and Henry constants, are particularly valuable for high-throughput screening and predicting separation performance. Recently, machine learning potentials (MLPs) have emerged as a powerful tool, offering near-ab-initio accuracy with high computational efficiency. While MLPs have been extensively applied in molecular dynamics simulations, their integration into Monte Carlo (MC) simulations for adsorption remains largely untapped. This limitation arises primarily because mainstream MC simulation codes are designed for empirical force fields and lacks native support for MLPs. In this work, we developed a flexible Python package, high-throughput vniversal learning-enabled utility for adsorption (HULU), to bridge this gap. We present the first demonstration of calculating full adsorption isotherms using state-of-the-art foundation MLPs (MACE-MATPES-PBE-0, NEP89, and ORB v3). Furthermore, we systematically benchmark these models against standard baselines, such as available experimental or density-functional-theory calculation data, and elucidate the microscopic origins of deviations in the simulation results. Ultimately, HULU paves the way for incorporating high-fidelity MLPs into high-throughput screening workflows, significantly enhancing the predictive design of nanoporous materials for energy and environmental applications.

Precise regulation of the crystalline phase of metal–organic frameworks (MOFs) is crucial for tailoring their pore structures and separation performance. Herein, with the reactants held constant and only the temperature and concentration varied, we achieved precise control over the phase formation region in the synthesis of Ni-based MOFs, enabling the selective preparation of three phase-pure Ni-MOFs: Ni(BTC)(DMF)2 (1), Ni3(BTC)2(Me2NH)3 (2), and Ni6(BTC)2(DMF)6 (3). A comprehensive investigation of the synthetic parameters clearly delineated the phase boundaries. Importantly, the use of high reactant concentrations in the preparation of 3 renders the process readily scalable, producing over 110 g of product in a single batch at a very low cost of 0.159 $/g, which represents the lowest raw material cost among reported MOFs for one-step purification of C2H4 from C2H2/C2H4/CO2 mixtures. Single-component adsorption measurements demonstrate that all three Ni-MOFs exhibit stronger adsorption toward C2H2 and CO2 than toward C2H4; notably, 3 delivers the highest IAST selectivity, with CO2/C2H4 and C2H2/C2H4 selectivities of 5.4 and 56.2, outperforming most benchmark adsorbents for one-step C2H4 purification from C2H2/C2H4/CO2 ternary mixtures. Theoretical calculations verified that C2H2 and CO2 exhibit more numerous and stronger interactions with the framework than C2H4. Dynamic breakthrough experiments further confirm that 3 enables efficient one-step purification of C2H4. This work demonstrates that precise phase-region regulation enables the preparation of a scalable and low-cost Ni-MOF, providing a highly promising candidate for one-step C2H4 purification.

Water scarcity in arid regions has become an urgent global challenge, highlighting the need for efficient freshwater production technologies. Sorption-based atmospheric water harvesting (SAWH) offers a promising approach, with its core relying on high-performance sorbents and practical device design. Among various candidates, metal-organic frameworks (MOFs) attracted considerable attention, but biocompatibility is essential for drinking water collection. This requirement motivates the investigation of cyclodextrin-based MOFs (CD-MOFs), which feature green synthesis, non-toxicity, and even digestibility. Herein, three CD-MOFs (alpha-CD-Na, beta-CD-K, and gamma-CD-K) were synthesized and systematically evaluated, revealing beta-CD-K as the most promising SAWH sorbent. It exhibits an almost S-shaped water sorption isotherm, relatively high water uptake, robust structural stability, and the potential for scalable preparation. We further investigated its water adsorption mechanism and identified optimal operating conditions. Finally, a portable, sunlight-driven SAWH device was designed to harvest freshwater under real outdoor conditions. Under identical conditions, beta-CD-K produced 12.5 mL of water, equal to 0.47 L & sdot;kg-1 per day. This offers valuable insights for the design of portable water collection devices.

The introduction of functional groups onto the ligands of flexible metal-organic frameworks (MOFs) enables the precise modulation of structural flexibility, allowing for the systematic tuning of gate-opening pressures for specialized gas separation. Herein, by precise regulation of the number and substitution positions of methyl groups in Zn(BDC-x)(Bipy-x)0.5, a new class of functionalized frameworks was successfully developed. Modulating the framework phase-transition energy barrier by tuning the position and number of the methyl groups led to a dramatic shift in the C3H6 and C3H8 gate-opening pressures. By rationally optimizing the structural flexibility and gate-opening characteristics, we obtained TYUT-28, a benchmark material capable of complete discrimination between C3H6 and C3H8. At 318 K and 0.5 bar, the optimized framework achieved a high C3H6 uptake (32 cm3 g-1) and a C3H6/C3H8 uptake ratio of 17.5. The C3H6-induced structural transition was elucidated using high-resolution synchrotron X-ray diffraction and microcrystal electron diffraction. The gate-opening behavior of C3H6 and C3H8 during adsorption was further investigated by in situ variable-pressure X-ray diffraction and in situ infrared analysis. This work highlights methyl substitution as an effective handle for tuning adsorption-induced flexibility and gate-opening pressure, enabling efficient C3H6/C3H8 separation.

Metal-organic framework (MOF) nanosheet membranes are promising for H2 purification because their highly tunable pore networks permit precise control of the sieving aperture. However, unavoidable linker rotation in MOFs impedes precise molecular sieving, with the impact further amplified in low-dimensional 2D nanosheets due to increased conformational freedom. Herein, we establish a rational rigidity-control strategy in heterobimetallic Zn(100-x)Cox(Bim)(OAc) nanosheets achieved by in-situ dual-metal integration. Moderate Co2+ incorporation reinforces the framework rigidity while preserving structural integrity, which sharpens molecular sieving. At an optimal Co2+ content of -30 %, the Zn(100-x)Cox(Bim)(OAc) nanosheet membrane exhibits an exceptional H2/CO2 selectivity of 243, a 180 % improvement over the more flexible Zn(Bim)(OAc) membrane. However, excessive Co2+ incorporation induces structural disorder, demonstrating that an optimal balance between rigidity enhancement and structural integrity is crucial for maximizing separation performance, providing an opening avenue for rational design in 2D MOF nanosheet membranes.

Developing porous adsorbents for propylene/propane (C3H6/C3H8) separation faces the challenge of integrating high adsorption capacity with fast adsorption kinetics. Herein, we address this challenge through precise pore control in a slightly flexible metal azolate framework NUM-27a, enabling synergistic equilibrium-kinetic separation of C3H6/C3H8. The periodically expanded throat gate enables effective impeding the diffusion of C3H8, while a large pocket-shaped cavity decorated with exposed oxide groups facilitates exceptional C3H6 capture at low pressures. Specifically, NUM-27a achieves exceptional low-pressure C3H6 capture (89.61 cm3 cm-3 at 0.1 bar) and a record C3H6 packing density (310.0 g L-1 at 0.01 bar). Kinetic analysis further reveals effective diffusion coefficient for C3H6 is 1.57 × 10-4 s-1 at 298 K. Gas-loaded single crystal X-ray diffraction analysis coupled with computational simulations elucidate that the intrinsic pore geometry underpins the unique adsorption and separation performance. Breakthrough experiments validate the outstanding separation performance of NUM-27a for C3H6/C3H8 mixtures. Moreover, the great stability, recyclability, and low-cost precursors of NUM-27a underline its potential as a reliable adsorbent for C3H6/C3H8 separation. The work unveils the adaptive throat-sieving gate strategy with optimal separation performance for challenging gas separations.

The adsorption separation process, which selectively adsorbs ethane (C2H6) from an ethane/ethylene (C2H4) mixture, has emerged as a promising alternative to energy-intensive cryogenic distillation for obtaining highpurity C2H4. However, the development of an adsorbent that overcomes the inherent trade-off between selectivity and adsorption capacity in gas separation processes, while exhibiting favorable kinetic separation properties, is expected to provide a substantial advancement for energy-efficient gas separation technologies. In this study, we present AlPO4-34, a crystalline aluminum phosphate (AlPO) zeolite characterized by a regular ultramicroporous framework. Its pores can induce optimal spatial confinement, enabling efficient C2H6/C2H4 separation through synergistic thermodynamic and kinetic mechanisms. Specifically, AlPO4-34 exhibits an exceptional C2H6 adsorption capacity of 52.95 cm3/g at 298 K and 1 bar, ranking second to the highest value reported for zeolites to date, with a higher C2H6/C2H4 selectivity of 2.12. For the first time, kinetic studies were conducted on an C2H6-selective zeolite adsorbent, revealing that the diffusion rate of C2H6 within this zeolite is markedly higher than that of C2H4. Breakthrough experiments confirm the sample's capability for complete separation of C2H6/C2H4 mixtures. The pressure swing adsorption (PSA) simulation further indicate that AlPO4-34 is a highly promising candidate for the selective separation of C2H6/C2H4 mixtures, holding great potential for industrial applications in C2H4 purification.