Abstract Efficiently sieving C 2 H 2 from CO 2 remains a significant challenge due to their similar molecular sizes and physical properties. To address this issue, we developed a novel strategy for selectively sieving C 2 H 2 from CO 2 by functionalizing metal–organic frameworks (MOFs) with imidazole‐based ionic liquids (ILs). The constructed model material, MIL‐101‐Cr‐EMImCl (EMImCl = 1‐ethyl‐3‐methylimidazolium chloride), exhibits both a high C 2 H 2 capacity (94.2 cm 3 g −1 at 298 K and 1.0 bar) and outstanding C 2 H 2 IAST selectivity over CO 2 (2.43), which are 1.7 and 1.5 times higher than those of the control (MIL‐101‐Cr), respectively. This highlights the critical role of IMIL functionalization in enhancing the C 2 H 2 /CO 2 separation performance of MOFs. This work not only positions the IL‐functionalized MIL‐101‐Cr‐EMImCl as a promising candidate for efficient C 2 H 2 /CO 2 separation, but also introduces a novel strategy for developing advanced C 2 H 2 /CO 2 separation adsorbents through the incorporation of ILs into porous materials.
Abstract This work presents a comprehensive experimental and modeling framework to describe and predict the volatile fatty acids (VFA) permeation in commercial polymeric nanofiltration (NF) and reverse osmosis (RO) membranes. The permeation behavior was evaluated using single‐ and multicomponent VFA solutions under varying feed concentration, pH, and transmembrane pressure. Permeate flux increased with increasing pressure and decreasing feed concentration, pH, and aliphatic chain length. The RO membrane exhibited significantly higher rejection (50%–90% at pH 3 and 90%–100% at pH 6) compared to the NF membrane (approximately 0% at pH 3 and up to 40% at pH 6), while the latter provided higher permeate flux. All experimental results were described using the solution‐diffusion model coupled with boundary layer model. The findings suggest that selective fractionation of VFA is limited by intrinsic transport and solute losses, whereas concentration via RO operated at pH above the acids' pK a is more feasible.
Abstract Membrane separation technology exhibits significant advantages for helium extraction from low‐helium natural gas. Nevertheless, its performance remains constrained by the inherent trade‐off between permeability and selectivity. Here, we systematically tailor the nanoscale architecture of copolyimide membranes by adjusting the ratio of 9,9‐bis(4‐amino‐3‐chlorophenyl)fluorene (CFDA) to 9,9‐bis(4‐amino‐3‐fluorophenyl)fluorene (FFDA), enabling selective separation of He/CH 4 and He/N 2 . At a CFDA/FFDA ratio of 1:3, the membrane shows a moderate fractional free volume (FFV = 24.06%), which restricts the diffusion of CH 4 more effectively than that of He, leading to a He/CH 4 selectivity of 78.0. At a ratio of 1:5, the denser structure (FFV = 23.72%) with a lower FFV enhances size‐exclusion for N 2 , achieving a He/N 2 selectivity of 37.7. Both membranes exhibit excellent 210‐day stability and maintain high selectivity in a ternary mixture (He/CH 4 /N 2 = 0.5/98/1.5, vol%). This work elucidates the composition‐nanostructure‐performance relationship, offering a rational design strategy for targeted gas separation membranes.
Abstract The spreading and evaporation of liquid droplets on hot particle surfaces are critical to liquid‐sprayed fluidized bed design. While coarse‐grid approaches (CFD‐DEM, Euler–Euler) are commonly used in reactor‐scale simulations, they lack resolution of microscale interfacial phenomena at the single particle level. This work performs high‐fidelity Volume‐of‐Fluid (VOF) simulations coupled with an interface evaporation model to investigate droplet impact and evaporation on heated spherical particles over wall temperature of 250°C–400°C and Weber number of 8–84. Results show that total evaporation time is insensitive to particle temperature, while droplet morphology and evaporated mass strongly depend on wall temperature and Weber number. Moreover, an effective evaporation area coefficient derived from VOF simulations is introduced as a correction factor for macroscopic models, enabling coarse‐grid simulations to retain essential microscale physics without explicitly resolving interfaces. It is expected to improve predictive accuracy for simulation of liquid‐sprayed fluidized bed with coarse‐grid approaches.
Abstract Extraction of lithium from magnesium‐rich salt‐lake brines using polyamide nanofiltration (NF) membranes is hindered by incomplete mechanistic understanding of ion separation in mixed‐salt environments. Conventional models struggle to decouple the intertwined effects of steric hindrance, Donnan exclusion, and multi‐ion competition, yielding contradictory design principles. Here, we develop a mechanism‐embedded machine‐learning framework that integrates empirical membrane descriptors with physics‐informed steric ( φ S ) and Donnan ( φ D ) partitioning factors derived from Donnan–steric pore model (DSPM). The framework reveals a paradigm shift in mixed‐salt systems: Li + /Mg 2+ selectivity is governed by Li + ‐controlled transport accessibility, not by the exclusion strength of Mg 2+ . Bivariate partial dependence plots (PDPs) identify a narrow high selectivity window, constrained to φ D ‐Li + ≈ 2–2.35 and φ S ‐Li + < 0.08. This work offers a quantitatively interpretable framework that reconciles single‐ and mixed‐salt separation mechanisms and demonstrates that robust Li + /Mg 2+ separation requires balancing between Li + permeability and Mg 2+ rejection, not extremizing individual membrane properties.
Abstract The transition to a carbon‐circular economy requires efficient technologies for converting CO 2 into value‐added chemical feedstocks. Sonocatalytic CO 2 conversion has recently emerged as a compelling approach to drive this conversion. Here, we report a surface‐roughened Cu x O catalyst for sonocatalytic CO 2 reduction in aqueous media, achieving a marked CO 2 ‐to‐CO conversion alongside H 2 production, yielding tunable syngas (CO/H 2 ) ratios relevant to Fischer–Tropsch and methanol synthesis processes. We demonstrate that the CO/H 2 ratio is systematically controlled by varying the solution composition (KHCO 3 , CH 3 COOK, and KCl), revealing solution‐mediated selectivity as an unexplored lever in CO 2 sonocatalytic systems. Prolonged testing in CO 2 ‐saturated KHCO 3 solutions induced morphological deformations of the Cu x O catalyst which were shown to benefit sonolysis, as evidenced by higher CO production rates during long‐term operation. Our findings highlight surface‐roughened Cu x O catalyst for sonocatalytic conversion of CO 2 ‐saturated solutions to syngas and introduce solution engineering as a new approach to tune product selectivity.
Abstract The oxygen reduction reaction (ORR) remains a central kinetic bottleneck in fuel cells. Its performance depends not only on catalyst activity, but also on electron/proton transfer, oxygen transport, and surface reaction kinetics. Because catalytic reactions and mass transport occur on different timescales, their matching is essential for efficient ORR. Covalent organic frameworks (COFs) have attracted increasing interest in ORR electrocatalysis because of their tunable structures and ordered pores. However, current studies mainly focus on material classification or activity regulation, while the relationship between transport and reaction kinetics remains insufficiently understood. To bridge this gap, this review proposes a transport‐reaction coupling framework for COF‐based ORR electrocatalysts. By comparing pyrolyzed and non‐pyrolyzed COFs, a key principle is revealed: electron, proton, and oxygen transport should be balanced with regulation of the local reaction environment. This review links molecular COF design, multiscale transport, and device performance to guide the design of COF‐based ORR electrocatalysts.
Abstract Deep eutectic solvents (DESs) have considerable potential for NH 3 capture, but traditional solvent screening methods are unable to identify appropriate DES efficiently. One thousand nine hundred fifty‐nine experimental solubility data points for 72 DESs were used to construct and compare multiple machine learning models based on σ‐profile descriptors to predict NH 3 solubility in DESs. CatBoost achieved the best performance ( R 2 = 0.993, RMSE = 0.079). Nested cross‐validation and independent test sets confirmed that the model has good physical consistency and cross‐system generalization. SHAP analysis further quantified the contributions of key features. The final model was then employed to predict the NH 3 solubilities of 1140 DESs, and the highest‐ranked systems were selected for subsequent characterization and absorption experiments. The results of the gas absorption performance experiment are in excellent agreement with the predictions of the model. Finally, quantum chemical calculations were used to clarify the microscopic mechanisms underlying DES formation and NH 3 interaction.
Abstract The practical application of metal–organic frameworks (MOFs) for CO 2 capture requires balancing high efficiency, cyclability, and scalable production. Herein, we report a novel MOF adsorbent, Cu 3 (ntrz) 2 (ox) 2 , which allows for low‐cost and scalable synthesis in aqueous solutions under ambient conditions. Its tailored large pocket‐like cavities interconnected by narrow pore apertures provide exceptional CO 2 adsorption capacities of 6.80 and 3.48 mmol g −1 at 1.0 bar and 0.15 bar (298 K), achieving a record‐high VPSA working capacity of 5.03 mmol g −1 within 0.05–1.0 bar. Shaped pellets retain 95% CO 2 adsorption capacity and good mechanical strength, fulfilling industrial requirements. Experimental VPSA analysis demonstrates that a 15% CO 2 gas‐stream can be enriched to 91.37% and 95.06% with productivities of 0.402 and 1.86 m 3 t −1 h −1 within 0.08–1.0 bar and 0.08–6.0 bar, outperforming zeolite 13X. The adsorption behaviors and mechanisms are elucidated via Grand Canonical Monte Carlo and dispersion‐corrected density functional theory simulations.
Abstract The practical deployment of covalent organic frameworks (COFs) for industrial gas separations is hindered by synthetic complexity, high monomer costs, and insufficient stability. We report a pyridine‐functionalized, vinylene‐linked COF (2,4,6‐trimethylpyridine‐terephthalaldehyde‐COF [TMP‐TPA‐COF]) that overcomes these barriers. Synthesized from inexpensive monomers (TMP and TPA) via one‐pot Knoevenagel condensation, TMP‐TPA‐COF has robust C=C linkages enabling hectogram‐scale synthesis. It exhibits a surface area of 1467 m 2 g −1 and static sulfur dioxide (SO 2 ) adsorption of 14.8 mmol g −1 at 25°C. Under simulated flue gas (6000 ppm SO 2 , 15% CO 2 , balance N 2 ), dynamic breakthrough shows a working capacity of 1.51 mmol g −1 and high selectivities, driven by Lewis acid–base interactions with pyridine sites. It is fully regenerated at 120°C under N 2 , retaining 95% capacity over 15 cycles. Its monomer cost is orders of magnitude lower than benchmark COFs, challenging the view that COFs are impractical for large‐scale applications and establishing a cost‐effective sorbent for deep SO 2 removal.
Abstract Tuning hydroxyl defects and constructing active sites at the molecular level is critical for rational design of propane dehydrogenation (PDH) catalysts and understanding the structure–activity relationship. For practical application, enhancing catalysts anti‐coking performance is equally important. Herein, the simultaneous regulation of hydroxyl nests content and b ‐axis thickness was achieved by adjusting the urea/SiO 2 ratio during the preparation of Silicalite‐1. The propylene formation rate of the catalysts prepared by introducing Zn species showed a linear positive correlation with the hydroxyl nests content, and the coking behavior was governed by the b ‐axis thickness of the support. The optimized ZnO x /Silicalite‐1 exhibited a high propylene space time yield of 2.2 kg h −1 kg cat −1 with propane conversion of 31% at 550°C. This work provides novel insights into PDH catalyst design from both chemistry and chemical engineering views.
Abstract Copper‐based catalysts dominate electrocatalytic nitrate reduction to ammonia (NO 3 RR), yet suffer from an intrinsic activity‐stability trade‐off due to strong NH 3 intermediates adsorption on Cu active sites, which accelerates catalyst deactivation at high activities. Herein, we regulate the d‐band center (εd) of Cu sites through Cu + /Cu 0 heterostructure engineering to facilitate NH 3 desorption while preserving efficient nitrate conversion. Electrochemical kinetics and DFT calculations identify NH 3 desorption as a critical kinetic limitation during NO 3 RR and reveal that εd downshifting weakens NH 3 binding and promotes its removal from the catalyst surface. This electronic modulation simultaneously suppresses Cu leaching (7.9‐fold reduction) and lowers the NH 3 desorption barrier. The optimized catalyst achieves an NH 3 yield rate of 6.6 mg h −1 mg cat −1 with a Faradaic efficiency of 97.9% at −0.8 V in 500 ppm KNO 3 , while retaining over 95% activity after 24 consecutive cycles. This work establishes electronic‐structure regulation as an effective strategy for durable, high‐performance NO 3 RR catalysts.
Abstract Distillation still is the most widely applied thermal separation process in the chemical industry, but high energy demand goes along with it. Electrification and minimizing industrial column's energy demand are essential from an economic and ecological perspective. A lever to minimize energy demand and thermal stress on specialty chemicals is the development of novel structured packings with minimized pressure drop. These can now be realized by additive manufacturing. To fully exploit this potential, mathematical optimization techniques need to be applied. For the first time, a highly efficient computational fluid dynamics (CFD)‐based adjoint shape optimization method is applied in structured packing design with minimized pressure drop. The design approach, embedded in a holistic development method, is presented. Selected results of a shape optimization study of a Rombopak basic element reveal a 13.7% reduction in pressure drop at constant specific surface area. The design method contributes to the development of next generation structured packings.
Abstract Three novel hydrophobic deep eutectic solvents (HDESs) based on tributyl phosphate as a hydrogen bond acceptor were designed for selective UO 2 2+ extraction from simulated seawater. Using octanoic acid or 2‐thenoyltrifluoroacetone as hydrogen‐bond donors, the HDESs achieved >96.671% extraction efficiency at low dosages within short contact times, with excellent selectivity in the presence of competing ions. The solvents were efficiently regenerated and exhibited good stability over multiple cycles. Proton nuclear magnetic resonance spectra, Fourier transform infrared spectra, and density functional theory calculations elucidated the formation mechanism and coordination interactions. Life cycle assessment further provides process‐level guidance for future scale‐up, highlighting efficient phase management and solvent reuse as key factors. This work establishes a recyclable platform for uranium recovery from seawater, supporting sustainable nuclear fuel cycles.
Abstract The hierarchical pore structure of industrial catalyst particles, spanning nanometers to hundreds of micrometers, eludes any single technique. This study, for the first time, integrates four complementary methods—scanning electron microscopy, N 2 physisorption, mercury intrusion porosimetry, and x–ray micro–computed tomography (micro–CT)—to systematically characterize an oxidative coupling of methane (OCM) catalyst. A full–range pore model is constructed, revealing a multimodal differential pore volume distribution and a radial gradient: both porosity and average pore size decrease from the particle center toward the periphery. Using these parameters, a single–particle computational fluid dynamics (CFD) model is developed, coupling mass, momentum, and heat transfer with kinetics. The simulation yields an effectiveness factor of 0.639, indicating moderate internal diffusion limitations. This work demonstrates that micro–CT enables quantitative 3D pore analysis of industrial catalysts and that the experimentally observed non–uniform pore distribution is essential for accurate CFD prediction of catalyst performance.
Abstract The development of uranium separation materials is essential to ensure a stable uranium supply for energy and to mitigate environmental risks. We report a two‐dimensional ferrocene‐vanadyl phosphate composite (fc‐VOP) with expanded interlayer spacing (9.8 Å) and adsorption–reduction coupling function, made by solvent‐assisted intercalation. This enables efficient uranium capture via optimized interlayer structure and interfacial properties. Interlayer expansion facilitates uranyl ion transport, accelerating adsorption kinetics, while the coupling function elevates interfacial concentration gradients to enhance ion binding, boosting capacity. The fc‐VOP shows a theoretical adsorption capacity of 1968.60 mg/g (pH = 4, pure nitrate solution) with equilibrium in 30 min. It also performs well in spiked matrices, achieving 336.4 mg/g in leachate and 248.2 mg/g in seawater. This work provides a viable route to improve 2D phosphate materials for uranyl adsorption and offers mechanistic insights into designing adsorption–reduction coupling materials.
Abstract Introducing defects into metal–organic frameworks (MOFs) offers a powerful strategy to tune their local microenvironments and boost catalytic performance. Herein, we report a “truncated linker” approach to construct defect‐engineered Cu(I)‐carbon covalent bonded frameworks (dMOF‐ x %PA). Using propargylamine as a chain‐terminating monomer, we deliberately create missing‐linker defects, which not only tune the porosity but also introduce additional Lewis basic (–NH 2 ) sites and improve the accessibility of Cu(I) active centers. The optimized TEPT‐dMOF‐30%PA exhibits exceptional activity in the carboxylation of terminal alkynes using atmospheric‐pressure CO 2 . Under mild conditions (80°C, 0.1 MPa, 6 h), it achieves a 96% yield of phenylpropiolic acid, outperforming both its defect‐free counterpart and most reported heterogeneous catalysts. Moreover, the catalyst shows excellent recyclability and structural stability. Combined in situ fourier‑transform infrared spectroscopy (FT‐IR) spectroscopy and density functional theory (DFT) calculations reveal a synergistic catalytic mechanism. This work establishes a general paradigm for designing robust, defect‐engineered MOFs with tailored microenvironments for efficient and sustainable CO 2 conversion.
Abstract Amine‐impregnated sorbents (AIS) have been extensively investigated for direct air capture (DAC) due to their high adsorption capacity and selectivity toward atmospheric CO 2 . However, there has been limited attention given to efficiently recovering the adsorbed CO 2 from AIS, leading to the regeneration remaining energy‐intensive in DAC systems. Here, we employ a double‐layered adsorption configuration, in situ producing vapors using water synergistically harvested from the air to effectively regenerate polyethylenimine‐impregnated sorbents. This vapor‐promoted regeneration provided a substantial driving force for CO 2 desorption at ambient pressure and 105°C, producing water and 99% purity CO 2 with a high working capacity of 1.61 mmol/g. Only 8.9 MJ/ thermal energy was consumed for sorbent regeneration without the use of vacuum conditions and external purge. This in situ vapor purge enables the recovery of over 95% of the CO 2 adsorbed on AIS, paving the way for the practical application of low‐cost chemisorbents in DAC.
Abstract Plasma‐assisted carbon dioxide (CO 2 ) conversion in gas–liquid systems provides a potential pathway for carbon utilization under ambient conditions, yet its performance is often constrained by gas–liquid transport. This work investigates CO 2 conversion in a water‐filled dielectric barrier discharge (DBD) reactor by correlating discharge characteristics, bubble dispersion pattern, and conversion performance. High‐speed visualization reveals that the plasma discharge suppresses bubble coalescence and promotes breakup, shifting the bubble size distribution from a coarse unimodal population to a finer and more dispersed pattern. This transition is accompanied by increased bubble number density, enhanced interfacial renewal, and stronger bubble‐induced flows, thereby intensifying gas–liquid mass transfer. Correspondingly, the apparent gas‐phase CO 2 removal index reaches approximately 30% at low gas flow rates but decreases markedly with increasing flow rate, where hydrodynamic effects become dominant. The results suggest that conversion in gas–liquid DBD systems is closely associated with plasma‐modified bubble dynamics, providing mechanistic guidance for optimizing plasma‐assisted CO 2 conversion processes.
Abstract The separation of mono‐ and di‐branched alkane isomers is an industrially important yet highly challenging process requiring precise pore structures. Here, we report a scalable metal–organic framework, Ni 3 (H 1.5 BTC) 2 (BTC)(DABCO) 3 (denoted as Ni‐HDB), featuring an anisotropic, “bat‐shaped” pore window that enables precise discrimination of the sterically similar 3‐methylpentane (3MP) and 2,3‐dimethylbutane (23DMB) pair (~0.3 Å difference in kinetic diameter), thereby enabling efficient separation of mono‐ and di‐branched isomers. Multicomponent vapor‐ and liquid‐phase experiments, supported by molecular simulations, reveal that separation arises from shape‐governed molecular accommodation rather than simple size exclusion. Notably, under industrially relevant liquid‐phase conditions, a packed column of pelleted Ni‐HDB directly produces a high‐octane gasoline fraction (RON > 91.5) from a five‐component alkane mixture, substantially exceeding the industrial benchmark of 83 for refined hexane mixtures. Combined with scalable synthesis, high stability, and low cost, this work establishes a practical, energy‐efficient route for liquid‐phase adsorptive upgrading of branched alkanes.
