Driven by the "dual-carbon" strategic goal, oil refining industry is increasingly focusing on refined processing and energy saving, and "molecular refining" technology has emerged as a key strategy for green innovation and high-quality development of the refining industry. Efficient separation of aromatics from petroleum hydrocarbons and providing high-quality raw materials for on-demand processing of aromatics are important technical approaches to realize the concept of "molecular refining". This study offered a comprehensive review of the current status of separation technologies for aromatic and non-aromatic hydrocarbons, as well as between different aromatic hydrocarbons. It further summarized the selection strategy of aromatics separation technology and proposed the main development direction for low-carbon industrialization of aromatics separation. These advancements are crucial for achieving the high-value utilization of aromatics and the sustainable development of the chemical industry

Enrichment and separation of uranium and lithium have significant importance for green energy and industrial upgrading. The reserves of uranium and lithium in seawater are thousands of times greater than those on land; however, their concentrations are extremely low. Hence, the efficient extraction of uranium and lithium from seawater based on photoelectrical-driven reduction and adsorption separation has emerged as one of the cutting-edge research areas in the fields of chemistry, materials, energy, and catalysis. This paper introduces the research progress of photoelectric drive to promote the extraction of uranium and lithium from seawater, focusing on the typical photoelectric drive extraction materials and processes, and summarizes the performance, advantages and disadvantages of photoelectric and electric drive to separate lithium and uranium from seawater. The new strategy based on photoelectric drive shows faster adsorption power and stronger capture ability for lithium and uranium extraction. We discuss the energy consumption and cost-effectiveness associated with the extraction of uranium and lithium from seawater, and anticipate the development trends, to inspire for the design and development of novel photoelectric extraction materials for extracting uranium and lithium from seawater.

Precisely controlling the thickness and pore structure of membrane materials at the atomic level and developing single atomic layer nanoporous membranes can significantly reduce mass transfer resistance and achieve molecular limit permeation and separation, which will bring new opportunities for the development of membrane separation and breakthroughs in difficult-to-separate systems. A variety of single layer nanoporous membranes (SLNM) materials are introduced, and their nanoporous construction methods and nondestructive transfer methods of single layer membranes are summarized, and their application status in gas separation, liquid separation, ion separation and other fields are discussed. Finally, the opportunities and challenges faced by single layer nanoporous separation membranes are analyzed and summarized, and its development direction is prospected.

As a high-performance composited membrane, bipolar membrane has been widely used for the conversion of salt into acid and alkali, energy storage and conversion, and acid-base flow battery. Under reverse voltage bias, water molecules in the middle layer of bipolar membrane in aqueous system can be dissociated into H⁺ and OH^-, and cooperate with anion and cation exchange membrane to form bipolar membrane electrodialysis, which is widely used in the desalination and acidification of high-salt wastewater. In addition to the aqueous system, bipolar membrane electrodialysis can also be used in water-alcohol system, such as the production of water insoluble organic acids. Meanwhile, the bipolar membrane can also realize the dissociation of alcohols into hydrogen ions and alkoxide ions, which is applied to the production of metal-alkoxides and green synthesis of organic chemicals. However, there are fewer studies that summarize the application of bipolar membrane in alcohol water systems. This review focuses on the progress of bipolar membranes electrodialysis in alcohol water systems, comparing the mechanism and electrochemical properties of water and alcohol dissociation. Moreover, it also points out the bottlenecks of alcohol dissociation in bipolar membranes, including high dissociation resistance, serious coion leakage caused by the swelling of membrane layers, etc. Finally, it is necessary to in-depth elucidate the dissociation mechanism of the mixed system and to prepare alcohol-tolerance bipolar membranes to realize the wider application of the bipolar membrane water-alcohol mixed and the alcohol system.

Metal organic frameworks (MOFs) have garnered extensive research interest in fields such as gas storage, adsorption separation, and catalysis due to their high surface area, large pore volume, and tunable structures. In recent years, the surge in the number of MOFs has posed unprecedented challenges in finding the ideal MOF for specific applications. In this scenario, high-throughput computational screening (HTCS) has become the most effective research method for screening high-performance target MOFs from a vast array of materials. HTCS will generate a large amount of multidimensional data, which can be further used for machine learning (ML) training. Recently, applying ML to HTCS of MOFs has become a new hotspot, which can not only reveal the potential structure-performance relationships of materials but also provide insights into their performance trends in different applications, especially in gas storage and separation. In this review, we highlight the latest advances in ML-assisted HTCS in the field of MOFs gas separation, systematically analyze the internal mechanism of ML and HTCS collaboration to improve screening efficiency in the search for high-performance MOFs, and explore the opportunities and challenges presented in this new field.

In industrial gas deoxidation technology, catalytic deoxidation methods have been widely applied due to their high efficiency and deep removal capability. The development of cost-effective, highly active, selective, and durable catalysts is pivotal for catalytic deoxidation technology. This article reviews the current research on gas deoxidation catalysts, elucidating their mechanisms of catalytic deoxidation across various scenarios. It summarizes the influence patterns of active components, promoters, and supports on catalytic deoxidation performance from the perspective of catalyst structural design. Low-temperature activity, poison resistance, and long-term stability are important objectives in the development of deoxidation catalysts. The strategies for constructing highly active and stable deoxidation catalysts are summarized, mainly including physical methods of spatial confinement and chemical methods such as alloying of active centers and strong metal-support interactions. Finally, based on the current research and application status of gas deoxidation catalysts, the study highlights non-noble metal deoxidation catalysts, (hydro)thermally stable single-atom deoxidation catalysts, and multifunctional deoxidation catalysts as significant trends in the future development of deoxidation catalysts.

Metal-organic frameworks (MOF) are a new type of porous materials constructed by metal ions or metal clusters with organic ligands through coordination bonds. They show advantages such as diverse structures, high specific surface area, high porosity, and diversified regulation of structures and properties. In recent years, MOF has gradually attracted attention in different fields such as adsorption/separation, catalysis, and sensing. However, the scale-up preparation of MOF faces many challenges, including stringent synthesis conditions, prolonged reaction times, reduced yields, and increased costs. Therefore, researchers are exploring various new synthesis methods, such as hydrothermal/solvothermal, rapid room temperature synthesis, solvent reflux, base-assisted, mechanochemical, electrochemical, microwave-assisted, spray-drying, ultrasonic, dry gel conversion, and accelerated aging methods. Thus, the methods for scale-up preparation of MOF are reviewed, and factors like cost, environmental impact, safety, and practical feasibility are assessed. Additionally, the article will briefly discuss advances in MOF shaping technologies to accelerate progress in those fields. The future challenges and opportunities for scale-up preparation and shaping of MOF materials are envisioned.

Metal-organic framework materials (MOFs) have shown great potential in various applications, including gas adsorption and separation, catalysis, and sensing due to their high specific surface area and porosity, adjustable pore sizes, and diverse structures. However, the synthesis of traditional MOF materials is mainly based on solvothermal method, which not only consumes a large amount of high-value organic solvents, but also has high energy consumption, low yield, and difficult waste liquid treatment in the production process, which does not meet the requirements of green development of chemical industry. The steam-assisted synthesis, which has the advantages of small solvent dosage, fewer reaction processes and shorter cycle time, has received extensive attention in the synthesis and modification of MOF materials in recent years, and it is expected to provide a new green and efficient pathway for the synthesis of MOF materials. This paper reviews the research advancements of MOF prepared by steam-assisted method, overviews the research progress of this method in the synthesis and modification of MOF materials. Additionally, the prospective developments of this synthesis method are discussed.

The advent of metal-organic frameworks (MOFs) glass materials serves to complement traditional MOFs materials effectively. With its unique melting characteristics and short-range ordered and long-range disordered ultra-microporous structure, it effectively avoids the intercrystalline defects in polycrystalline MOFs membranes and the incompatibility of phase interfaces in MOFs-based hybrid membranes, bringing new technical options to the field of gas separation membranes. The research history of MOFs glass materials is first reviewed, followed by a systematic summary of the preparation methods for MOFs glass. The latest advancements in the application of MOFs glass membranes in the field of gas separation are introduced. Finally, an analysis is conducted on the challenges faced by MOFs glass membranes in gas separation applications, and potential research directions and solutions are proposed.

Pervaporation membranes are an emerging membrane separation technology widely used in solvent recovery and environmental protection. Through the selective permeation and vaporization process, the pervaporation membrane can effectively separate water and organic solvents, especially suitable for treating waste liquid containing aqueous solvents, which can reduce environmental pollution and realize the recycling of resources. Unlike previous reviews on pervaporation separation membranes, this paper summarizes the research progress of hydrophobic pervaporation membranes from the perspective of polymer membranes as substrates, highlighting key issues that need to be addressed to guide further development in this field. In this paper, we first discuss the challenges faced by polymer-based hydrophobic pervaporation membranes in solvent recovery and the essential requirements for practical separation applications. We outline different methods to enhance membrane hydrophobicity, such as physical blending, surface structure control and intermediate layer construction, and summarize design strategies for polymer-based hydrophobic pervaporation membranes that possess the desired microstructure and surface characteristics. Second, we introduce the broad application prospects of polymer-based hydrophobic pervaporation membranes in solvent recovery, including the recovery of solvents such as alcohols, lipids, hydrocarbons and ketones. Third, the thermal stability and pilot-scale test cases of polymer-based hydrophobic pervaporation membranes have been introduced. Finally, we analyze the challenges faced by polymer-based hydrophobic pervaporation membranes in practical applications and outlines future research and development directions.

Metal-organic frameworks (MOFs) are a class of highly ordered porous materials composed of metal ions or metal ion clusters coordinated with organic ligands. MOF membranes have been widely used in the chemical separation. High-efficient synthetic and post-synthetic modification methods help to obtain continouous, defect-free and structurally diverse MOF membranes. Compared with traditional liquid-phase synthesis methods, vapor processing is a high-effcient and environmentally friendly method. Using a vapor processing method, we can cut down the consumption of solvents and precursors, avoid the competitive nucleation in a bulk solution, reduce the risk of membrane cracking as a result of the removal of solvent molecules in the post-treatment of membranes. In this review, we summarize the research progress in direct synthesis and post-synthetic modifications of MOF membranes by vapor processing, and highlight the achivenments in regulation and optimization of membrane performances by vapor processing. Finally, an outlook on future directions of vapor processing and its potential for large-scale production of MOF membranes were provided.

The oceans hold ca. 4.5 billion tons of uranium, which will provide sustainable production for the global nuclear industry more than thousands of years. Therefore, uranium extraction from seawater is considered as one of the world-changing chemical separation technologies. Membrane separation is widely used for uranium extraction from seawater because of its high efficiency, low energy consumption, and non-pollution. Metal-organic framework (MOF) holds great potential for seawater uranium extraction with membrane technology due to the tunable pore size, rich functionality, and diverse post-modification protocols. This paper reviews the latest research progress and future development direction of membrane separation technology in uranium extraction from seawater, and especially systematically summarizes the separation mechanism and challenges of uranium extraction from seawater using MOF membranes.

Membrane separation technology has been widely used in many fields due to its high efficiency and environmental friendliness. However, traditional membranes have limited adaptability in complex environments and are difficult to meet the ever-increasing separation needs. In contrast, smart responsive membranes can dynamically modify their structure and properties in response to external stimuli, such as light, temperature, pH, or electric fields, offering greater flexibility and improved performance across a wide range of applications. The development of novel porous organic polymers, such as covalent organic frameworks, metal organic frameworks, and conjugated microporous polymers, has paved the way for new possibilities in the design and optimization of these membranes. This review presents recent advancements in smart responsive membranes based on porous organic polymers, with a focus on how different external stimuli influence their structure and performance. Additionally, it explores various fabrication methods, strategies for integrating responsive groups, and addresses potential challenges along with future research directions in the field.

Helium, as a non-renewable noble gas, plays a vital role in scientific research and industrial production. Therefore, efficient and economical separation and purification of helium has significant research and application value. Membrane separation technology has emerged as a promising approach for helium purification owing to its low energy consumption and operational simplicity. Polymeric membranes, in particular, have garnered considerable interest due to their excellent flexibility, membrane-forming properties, and gas separation performance. This review summarizes the latest research progress of helium separation membrane materials such as polyimide, self-polymerized microporous polymer and fluorinated polymer in recent years, focusing on the processability, scale-up production and long-term stability (such as plasticization and physical aging) of helium separation membrane materials, and prospects for the development of helium separation polymer membrane materials and future development trends.

Separation and purification of low carbon hydrocarbon (C₁—C₃) mixtures is one of the key processes for sustainable development of the petrochemical industry. Physical adsorption separation technology has a potential for application in this field due to its advantages of low energy consumption, easy regeneration and simple operation. The key is to develop solid adsorption materials with low energy consumption and high selectivity for adsorption and separation of C₁—C₃ under mild conditions. Porous carbon has attracted extensive attention in the field of separation and purification of low-carbon hydrocarbons due to its excellent chemical stability, adjustable pore structure and surface chemical properties. Based on our recent progress, this paper reviews the research progress and separation mechanisms of porous carbon materials in the separation system of coal bed methane and olefin-alkanes from C₁, C₂, and C₃, with emphasis on the research results relating to the modulation of the pore structure and the surface polarity. Finally, we discuss the challenges faced by porous carbon materials in separating low carbon hydrocarbons, and envisage the future development direction, especially the potential of porous carbon materials in efficient and economic separation technology.

In recent years, metal-organic frameworks (MOFs) glass materials obtained by melt-quenching of MOFs have attracted the attention of many researchers. After melt-quenching treatment, MOF crystals transform from long-range ordered crystal states to short-range ordered and long-range disordered amorphous glass states. During the transformation process, MOF glass effectively eliminates non-selective grain boundaries, ensuring the uniformity and consistency of the material. The excellent processability and formability of MOF glass enable it to be easily prepared into membrane materials of various shapes and sizes. The permanent and accessible pore structure of MOF glass gives it the ability to selectively adsorb different types of gases. For this reason, MOF glass is expected to become a candidate material for high-performance separation membranes, promoting the continuous development of related research and applications. This article reviews the melting mechanism, classification, and latest research progress of MOF glass membranes used for gas separation. In addition, this article also discusses the challenges faced in the membrane production process and proposes possible future research directions.

Lignocellulosic nanofibril (LCNF) aerogels have the advantages of high porosity, low density, renewable and reusable raw materials, but their insufficient mechanical properties limit their application in the field of oil-water separation. To address this issue, LCNF/polyimide (PI) composite aerogels were created using freeze-drying and chemical vapor deposition. The results show that the strong hydrogen bond between PI and LCNF endowed aerogels with good mechanical and oil-water separation performance, with elasticity modulus ranging from 9.69 to 11.88 kPa and oil-absorption multiplicity ranging from 73.0 to 103.4 g·g^-1. Compared with M-LCNF aerogels, the elastic modulus of M-LCNF/PI aerogels increased by 1.459—2.015 times, and the adsorption capacity for a variety of organic solvents and oils increased by 1.6—21.0 g∙g^-1. M-LCNF/PI-1.00 aerogels maintained low density (8.66 g∙cm^-3), excellent hydrophobicity (water contact angle of 140.6°), good thermal stability (maximum decomposition rate temperature up to 363.1℃) and excellent thermal insulation performance of 0.04436 W∙m^-1∙K^-1. The adsorption of vacuum pump oil by M-LCNF/PI-1.00 was more consistent with a quasi-secondary kinetic model. The M-LCNF/PI-1.00 still retained 79.1% of the original adsorption capacity after 5 times of extrusion adsorption of anhydrous ethanol, showing good reusability and providing a new strategy for preparing high-performance oil-absorbing materials.

In the thin film deposition process of integrated circuits, electronic-grade diethoxymethylsilane (DEMS) is a key precursor for the fabrication of low dielectric constant silicon-based semiconductor films. Its organic purity is required to reach 99.990% (mass, 4N), total metal ion impurity content ≤5.000 μg/L, and individual impurity content ≤0.500 μg/L. It is difficult for the current process to meet the purity requirements, so the complete purification of electronic-grade DEMS is proposed to be purified by the vacuum azeotropic distillation process technology route, and the main work includes: (1) The purification difficulties of DEMS are analyzed through conventional distillation experiments, and carried out vacuum azeotropic distillation experiments to purify the key component impurity ethanol to less than 0.010%(mass), which reduces the purification difficulty of DEMS, and the organic purity reaches 4N; (2) Through conventional vacuum distillation experiments, the total metal ion impurity content ≤5.000 μg/L and individual impurity content ≤0.500 μg/L; (3) A vacuum azeotropic distillation model is established, and the model is verified using experimental results. The vacuum azeotropic distillation process is further established, and the model is used to optimize the design of the new process. The product indices of DEMS obtained from the results of the study have reached the electronic grade standard, which meets the requirements of the integrated circuit manufacturing process and lays a theoretical foundation for the large-scale and low-cost production of electronic-grade DEMS.

In view of the difficulty in removing trace sulfides from biodiesel, the acid-rich Ce-13X molecular sieve was constructed by ion exchange method and used in the adsorption desulfurization system of biodiesel. The phase composition, structure and morphology, acid strength, element valence and acidity were analyzed by a series of characterizations. The results showed that the introduction of Ce increased the concentration of strong B acid sites and weak L acid sites in 13X zeolite. Under the optimal experimental conditions (temperature of 40℃, agent-oil ratio of 1∶80), after 30 min, the sulfur content in biodiesel dropped from 8 μg·g^-1 to below the target concentration of 2 μg·g^-1. The adsorption kinetics showed that the adsorption process conformed to the quasi-second-order kinetic model and the whole adsorption process was mainly controlled by liquid film diffusion and intraparticle diffusion. The adsorption thermodynamics showed that the adsorption of mercaptan by Ce-13X was a spontaneous exothermic process. This study not only proposed a construction method of acid-rich 13X molecular sieve, but also constructed an efficient adsorption desulfurization system to achieve ultra-deep removal of trace sulfides in biodiesel.

As an emerging membrane material, the evolution of metal organic frameworks (MOFs) is gradually driving membrane separation technology towards precise molecular separation at the 1-nanometer scale. Zeolitic imidazolate framework-8 (ZIF-8), one of the most widely studied MOF materials, features a four-membered ring pore in the crystallographic <100> direction, with a critical diameter about 0.38 nm between the kinetic diameters of C₂H₄ and C₂H₆. A surfactant-assisted synthesis strategy was employed to synthesis {100}-oriented ZIF-8 nanosheets, which were used as building blocks to fabricate ultrathin, highly oriented ZIF-8 membrane. Microstructural characterizations and C₂H₄/C₂H₆ separation tests showed that the ZIF-8 membrane with highly oriented four-membered ring pores achieved precise C₂H₄/C₂H₆ separation. Under the conditions of 25℃ and 101 kPa, the ethylene/ethane separation selectivity reaches 6.8, the ethylene permeation rate reaches 7.33×10^-8 mol/(m²·s·Pa), and there is no performance degradation after continuous operation for 100 h. This work establishes the foundation for advancing both the theory and technology of MOF membranes in the separation of same-carbon-number hydrocarbon mixtures.

The sequential simulated moving bed has a variety of switching modes, low energy and water consumption, and can achieve continuous and efficient separation and purification of multi-component and difficult-to-separate systems. Previous studies have shown that the sequential simulated moving bed cannot simultaneously take into account the performance of purity and solvent consumption, so this project mainly focuses on improving the separation performance through structural regulation and optimization, furthermore developing a new operating mode with universal applicability. Firstly, xylooligosaccharide syrup was selected as the target system, and DOWEX MONOSPHERE^TM 99/310 K⁺ resin was used as the stationary phase to complete the corresponding separation experiment and process simulation in order to verify the accuracy of the model. The switching sequence control and switching mode modification of the sequential simulated moving bed were carried out by process simulation, and then the purity, yield and water consumption of the final product were compared. The results show that the new “circulation-feed-elution” mode performs well and can control water consumption while ensuring high purity and yield. Compared with the traditional structure of “feed-cycling-elution”, the purity and yield of the target product were increased by 33% and 37% respectively under the same operating conditions, and the water consumption was reduced by 2.79 ml/min. In addition, different modification methods can also regulate the separation performance, improve the diversity of products, and reduce the production cost. This study provides ideas and references for the industrial application and modification of the sequential analog moving bed.

Magnetic-induced temperature-swing adsorption has attracted much attention due to its convenient operation, fast heat generation, and short heat transfer distance. The energy efficiency of this method is determined by the performance of adsorbents in a magnetic field. The current adsorbent material performance is difficult to adjust and cannot fully exert its separation performance in magnetically induced temperature swing adsorption. In this paper, a magnetically responsive flexible adsorbent material MN@CPL-1 was constructed and applied to propylene capture. These composite adsorbents were obtained by in-situ synthesis of Fe₃O₄ nanoparticles with flexible MOFs. When the alternating magnetic field is turned off, MN@CPL-1 has an open pore structure which can effectively captures propylene molecules. When the alternating magnetic field is turned on, the heat induced by magnetism can be rapidly transferred from Fe₃O₄ nanoparticles to CPL-1, causing local rotation of its framework and promoting the release of propylene molecules. The working capacity of the optimal sample in the temperature range of 10—30℃ (22.5 cm³·g^-1) is superior to various classic propylene adsorbents, such as MIL-101 (14.45 cm³·g^-1), MAC-4 (13.00 cm³·g^-1), and zeolite 5A (4.14 cm³·g^-1). Under the control of an external magnetic field, the uptake swing of the optimal sample reaches 65.9%. After 5 cycles closure/opening of alternating magnetic field for adsorption and desorption, the composite maintained good reusability. The coupling of magnetic-induced heat generation and flexible structure of adsorption materials improves the adsorption efficiency.

Para-xylene (PX) is an important basic chemical raw material. The separation of PX from mixed xylenes (mixture of meta-xylene (MX), ortho-xylene (OX), and PX) is a prerequisite for its utilization. The complex crystallization method, combining complexation with crystallization, has great potential for separating PX from mixed xylenes. Three new crystals including 2PX·CuAlCl₄, 2MX·CuAlCl₄, and 2OX·CuAlCl₄ were obtained by complexing the bimetallic halide CuAlCl₄ with xylene isomers by π-complexation as a complexing agent. The melting points of these crystals were 41.0℃, 15.1℃ and 55.7℃, respectively. The solid-liquid equilibrium data of the binary systems 2PX·CuAlCl₄/2MX·CuAlCl₄ and 2PX·CuAlCl₄/2OX·CuAlCl₄ were further determined. Both were simple eutectic systems. The mole fraction of 2PX·CuAlCl₄ at the eutectic point was 0.3969 and 0.6107, and the corresponding temperatures were -3.36℃ and 14.83℃, which were 49.2℃ and 47.7℃ higher than those of the pure arene binary system, respectively. The temperature required for the crystallization operation was greatly increased. The phase equilibrium data were fitted by the ideal solution model, and the results showed that the model could be used to relate the solid-liquid phase equilibrium of the binary system. This provided a thermodynamic basis for the separation of mixed xylenes by bimetallic halide complex crystallization. A purity of 98% PX was obtained through initial crystallization, verifying the feasibility of the method.

At present, there are some problems in the helium extraction process, such as excessive dependence on the helium-rich tail gas from liquefied natural gas production process, the introduction of new impurities by catalytic oxidation destructive dehydrogenation and high energy consumption. Therefore, a multi-stage membrane-electrochemical hydrogen pump-adsorption helium extraction integration process based on a wide range of resources for helium-poor pipeline natural gas was proposed to produce diversified products of He, H₂, and CO₂ by utilizing the pressure of the pipeline natural gas and a multi-technology gradient productization strategy of removing impurities and extracting helium, so as to realize the economic helium extraction from helium-poor pipeline natural gas. Aspen HYSYS software was used to simulate and optimize the helium extraction integration process for 1.00×10⁵ m³/h helium-poor pipeline natural gas, and the effects of the recovery, membrane performance, and helium concentration on the process economy were investigated. The simulation results show that, at a typical pipeline natural gas pressure of 4.0 MPa and 0.04%(vol) He, the helium extraction integration process for helium-poor pipeline natural gas is more economical with the medium-permeable and medium-selective gas separation membrane, and the helium recovery rate is 50%—70%, the break-even price of helium is 115.5—123.2 CNY/m³, and the break-even price gradually decreases as the helium concentration increases, providing a technological route with great industrial prospects for the economic utilization of helium-poor resources.

Ethane is an important raw material in petrochemical production and can be used to produce chemicals such as ethylene. Separating ethane from natural gas can achieve effective utilization of resources. In this study, the methane/ethane mixture was separated by a new absorption-adsorption hybrid separation method. The separation medium was created by suspending ZIF-8 particles into N,N-dimethylpropyleneurea(DMPU). The results indicate that the slurry have a significantly higher absorption capacity for ethane than methane. The sorption rate in ZIF-8/DMPU slurry was fast, especially ethane reached adsorption equilibrium in 3—5 minutes. When the temperature was 283.15 K and the initial gas-liquid ratio was about 52.46, the separation factor of C₂H₆/CH₄ in ZIF-8/DMPU slurry could reach 9.26. In the column breakthrough tests, the slurry also showed excellent dynamic separation performance. In addition, the regeneration conditions of the slurry were mild and the structure of the recovered ZIF-8 material did not change. Continuous absorption-desorption cycle separation of C₂H₆/CH₄ can be achieved.

The lack of vapor-liquid equilibrium data for nuclear-pure grade uranium fluoride and related fluoride impurities has become a bottleneck in the development of China's dry-process uranium purification and conversion technology. However, the complexity and particularity of the physical properties of the system have brought great difficulties to the accurate determination of the data. Therefore, a high-pressure corrosion-resistant static vapor-liquid equilibrium measurement device was designed and developed. The saturated vapor pressure data of pure components VF₅ and MoF₆, as well as the isothermal vapor-liquid equilibrium data of the WF₆-MoF₆ binary system at different temperatures, were measured. Emphasis was placed on conducting a comprehensive error analysis and data correction from three perspectives: device design, operation process, and analysis and detection. The results show that the impact of gas-phase sampling on the liquid-phase composition is less than five ten-thousandths; there is an error of approximately 0.5% when considering the raw material composition as the liquid-phase composition; reducing the purge gas velocity of gas-phase sampling and decreasing the heating rate can reduce errors, etc. After correcting the experimental data based on the results of error analysis and estimation, the thermodynamic consistency test was passed. This provides a supporting means for accurately obtaining the thermodynamic data of vapor-liquid equilibrium of metal fluorides.

Co-MOF-74 and Mg-MOF-74 represent materials with strong and weak CO binding sites, respectively, and their CO adsorption capacities at room temperature and pressure cannot be evaluated for suitability in the CO/N₂ pressure swing adsorption process. The CO working adsorption capacity, regeneration and adsorption heat (Q_st) of Co-MOF-74 and Mg-MOF-74 and their corresponding operating temperature and adsorption-desorption pressure were studied by single-component static and two-component dynamic penetration experiments under different operating conditions. The results showed that when the CO/N₂ composition was 50%/50%, the optimal operating conditions for Co-MOF-74 were 100℃ and 3.0—0.2 bar (total adsorption-desorption pressure), with a working capacity and regenerability for CO of 2.85 mmol·g^-1 and 83.82%, respectively, for Mg-MOF-74, at 25℃, 2.0—0.2 bar, the working capacity and regeneration for CO were 1.63 mmol·g^-1 and 79.51%, respectively. The Q_st of Co-MOF-74 at 100℃ (34.57 kJ·mol^-1) is similar to that of Mg-MOF-74 at 25℃ (35.45 kJ·mol^-1), indicating that the Q_st of the adsorbents with different binding sites for CO was about 35.00 kJ·mol^-1, which is considered the optimal operating temperature. This study can provide a reference for the design of pressure swing adsorption process using adsorbents with different CO binding sites.

A cellulose nanocrystal (CNC)-doped sulfonated poly(ether ether ketone) (SPEEK) hybrid matrix membrane was designed for vanadium redox flow batteries. The abundant hydroxyl and sulfonic acid groups on the surface of CNC enhances its hydrophilicity and improves filler-polymer interfacial compatibility. Additionally, the high crystallinity and aspect ratio of CNC provide the membrane with high stability and effective ion barrier properties under harsh acidic and oxidative conditions. The abundant —OH groups on the CNC surface, combined with the —SO₃H groups in SPEEK, created interconnected hydrophilic ion nanoclusters, resulting in excellent proton conductivity of 0.073 S·cm^-1. The assembled battery using this membrane achieves a voltage efficiency (VE) of 88.7% at 120 mA·cm^-2, significantly surpassing that of the SPEEK membrane (78.3%), indicating that SPEEK/CNC membrane has good application prospects in all-vanadium liquid flow batteries.

The development of adsorbents for purifying methane (CH₄) from unconventional natural gas is of great significance for the sustainable development of energy and environment. However, the physical and chemical properties of CH₄ and N₂ are extremely similar, making the design of high-performance adsorbents a daunting challenge. Herein, an ultra-microporous metal-organic framework (Ni-BZZA) was constructed using a low polarity aromatic imidazole ring ligand 1H-benzimidazole-5carboxylic acid for efficient separation of CH₄/N₂ mixtures. The pore surface of Ni-BZZA has dense nitrogen heterocycles and accessible oxygen atoms that can serve as strong binding sites for CH₄. The ultramicroporous of Ni-BZZA provide strong constraints for CH₄. The synergistic effect of pore size and pore surface chemistry results in excellent CH₄ uptake (39.1 cm³·g^-1) and CH₄/N₂ (50/50, vol) selectivity (8.6) of Ni-BZZA at 298 K and 0.1 MPa. Breakthrough experiment conducted under simulated industrial conditions has confirmed that Ni-BZZA can efficiently separate CH₄/N₂ mixture. The excellent CH₄ uptake and CH₄/N₂ selectivity of Ni-BZZA indicate its great potential for enriching CH₄ in unconventional natural gas.

Based on first-principles calculations, 11 bimetallic organic framework Co/Zn-ZIFs molecular models (1#, 2#, 3#, etc.) were constructed. Each model has the same window structure. The adsorption properties of C₃H₆ and C₃H₈ on Co/Zn-ZIFs were studied by the Grand Canonical Monte Carlo method. The adsorption mechanisms of C₃H₆ and C₃H₈ on Co/Zn-ZIFs were analyzed by adsorption heat distribution, adsorption sites, weak interactions, electrostatic potential and differential charge density. Molecular dynamics was used to calculate the diffusion characteristics of C₃H₆ and C₃H₈ at the windows of Co/Zn-ZIFs. The results indicated that the adsorption of C₃H₆ and C₃H₈ on Co/Zn-ZIFs mainly occurs near the imidazole ring and methyl group of the ligands. Within a certain range, increasing the temperature and decreasing the pressure were both beneficial for achieving preferential adsorption of C₃H₈. At an ambient temperature of 323 K and a pressure of 0.5 bar, the ideal adsorption selectivity of C₃H₈ to C₃H₆ for 3# Co/Zn ZIFs is the highest, at 1.25. The diffusion free energy difference between C₃H₆ and C₃H₈ is the largest at the 6# Co/Zn-ZIFs windows, which is 14.60 kJ/mol. The self-diffusion coefficients of C₃H₆ and C₃H₈ are 3.910×10^-10 and 1.445×10^-12, respectively. The ideal diffusion selectivity of C₃H₆/C₃H₈ was the highest, as high as 270.59. For different Co/Zn-ZIFs molecular models with the same metal ratio have similar C₃H₆ adsorption capacities and C₃H₈ adsorption capacities. When the metal atoms with a small proportion are distributed alternately, the diffusion free energy of C₃H₆ and C₃H₈ is the highest, and the difference in diffusion free energy between C₃H₈ and C₃H₆ increases, thereby improving the separation selectivity of C₃H₆/C₃H₈. For Co/Zn-ZIFs molecular models with different metal ratios, they have similar C₃H₆ adsorption capacities and C₃H₈ adsorption capacities. As the Co/Zn ratio increases, the diffusion free energies of C₃H₆ and C₃H₈ molecules gradually increases, which increases the diffusion resistance of C₃H₆ and C₃H₈. These results provided valuable theoretical basis for analyzing the separation of C₃H₆/C₃H₈ mixtures by Co/Zn-ZIFs.

In recent years, metal-organic frameworks (MOF) have garnered significant attention due to their large specific surface area, highly tunable pore sizes, and diverse functionalities. These characteristics render MOF promising materials for applications in gas adsorption and separation, catalysis, and sensing. However, the majority of MOF materials remain confined to small-scale synthesis in laboratories. The large-scale production of MOF faces numerous challenges, including stringent synthesis conditions, low yields, and difficult post-processing, limiting their widespread application. Among the various MOF materials, MIL-101(Cr) has gained particular favor from researchers due to its exceptional thermal stability, chemical stability, and ultra-high porosity and specific surface area. MIL-101(Cr) can be synthesized via a simple hydrothermal method using relatively low-cost terephthalic acid and chromium salts, demonstrating significant potential for industrial applications. Nevertheless, in the conventional hydrothermal synthesis process, the small particle size of MIL-101(Cr) leads to difficulties in sedimentation and requires multiple washing steps, which limit the production efficiency. To address this issue, we introduced a flocculant and optimized the flocculation process by adjusting the types and amounts of flocculant used, thereby reducing filtration time and improving production efficiency. Importantly, after adding flocculants, the thermal stability of MIL-101(Cr) was maintained, the BET specific surface area reached 3211 m²/g, and the carbon dioxide adsorption reached 40 cm³/g, and the performance was well maintained.

The separation of neutral aromatic compounds from tobacco waste is one of the important ways to recycle waste tobacco resources. Polyvinylidene fluoride (PVDF) was used as the base membrane and zeolite imidazolate skeleton material ZIF-67 was used as the modified filler to prepare polydimethylsiloxane (PDMS) pervaporation composite membrane for separation of neutral aroma components of tobacco. SEM, contact angle measuring instrument, FTIR and XRD were used to characterize the physical and chemical properties of the composite membrane, and the performance of composite membrane for pervaporation of aromatic compounds was investigated. The results show that ZIF-67 is physically blended with the PDMS matrix, enhancing the hydrophobicity of the membrane. With the increase of ZIF-67 content, the permeation flux and separation factor increase firstly and then decrease. The pervaporation separation performance reaches its optimum when ZIF-67 filling content was 5%(mass). The maximum permeation fluxes of the ZIF-67/PDMS membrane are 3.61, 2.07 and 0.81 g·m^-2·h^-1, and the maximum separation factors are 115.5, 191.2 and 109.1 for 2-phenylethanol, damascenone and dihydroactinidiolide, respectively. The separation efficiency of the composite membrane for actual tobacco extract was investigated, and the average fluxes of the three aromatic compounds are 16.2, 11.6 and 9.8 mg·m^-2·h^-1, respectively.

Membrane separation is an efficient and energy-saving CO₂ separation technology. Intrinsic microporous ladder polymers are regarded as the superior materials for CO₂ separation technology due to their high porosity, high selectivity and stable structure. In this work, based on molecular dynamics simulation, a 3D-contorted CANAL ladder polymer membrane (named CANAL-Me-S5F membrane) is constructed, and the sorption as well as permeation performance of CO₂/N₂ mixture are investigated. To fully consider the flexibility of polymer membrane, most polymer chains can freely move during the simulation. The results show that the adsorption quantity of CO₂ in the membrane (4.00 mmol/g) is significantly larger than that of N₂ (0.30 mmol/g), which is mainly caused by the stronger interaction between CO₂ and membrane. The permeabilities of CO₂ and N₂ through the CANAL-Me-S5F membrane are 22546.09 Barrer and 1094.01 Barrer, respectively. The permselectivity {\alpha }_{P(\mathrm{C}{\mathrm{O}}_{\mathrm{2}}/{\mathrm{N}}_{\mathrm{2}})} (20.61) is in good agreement with reported experiment. The CANAL-Me-S5F membrane exhibits high permeability selectivity for CO₂ molecules, mainly due to the high solubility (i.e., preferential adsorption) of CO₂ in the membrane material. The research results provide theoretical support for the design and development of new polymer membranes for gas separati on.

Kr-85 is a widely used and valuable β-radionuclide, mainly present in the tail gas of spent fuel reprocessing. The recovery and purification of Kr-85 not only mitigate the environmental impact of radioactive gases, but also yield high-activity radiation sources. This study proposes a method to concentrate trace amounts of Kr in off-gas streams via low-temperature adsorption using different porous adsorbents, followed by further purification through chromatography to obtain high-purity Kr gas. Nano-scale pure silica MFI zeolite (Si-MFI) was synthesized, and its low-temperature adsorption-separation capacity for Kr gas was compared with various other adsorbents. The results indicate that Si-MFI exhibits the best adsorption-separation performance for Kr gas at 195 K. Consequently, Si-MFI was selected as the adsorbent for this study. Furthermore, the feasibility of the proposed approach was validated through breakthrough experiments in a fixed-bed setup and a custom-designed low-temperature Kr recovery apparatus. The results demonstrate that the device and the cryogenic enrichment-chromatographic purification process can effectively recover Kr from simulated exhaust gas with a concentration of 0.005% (vol). The purified Kr product is virtually free of nitrogen and oxygen impurities, thereby confirming the feasibility of the process.

Cylinder diameter is the core of cyclone separator size optimization, but different results are reported in the literatures on its effect on performance, and its flow field mechanism is rarely explored. In this study, under the conditions of controlling the inlet size of 145 mm × 63 mm, the inlet gas velocity of 27.5 m/s, and the other dimensions are proportional to the cylinder diameter, the effect of cylinder diameter on performance is investigated through performance tests; and the flow field mechanism is explored using computational fluid dynamics (CFD). The results show that the pressure drop decreases with increasing cylinder diameter, and the decrease in tangential velocity is the main cause. The separation efficiency increases and then decreases with the increase of cylinder diameter, and the optimum efficiency is about 410 mm. The flow field analysis shows that it is related to the following mechanisms: the tangential velocity and axial velocity of the airflow in the separator decrease with the increase of cylinder diameter, but the axial velocity decreases more, and the stagnation phenomenon occurs in a large cylinder diameter, and both of them work together to make the secondary separation capability of the internal cyclone for small particles increase with the increase of cylinder diameter. Therefore, the mixing escape rate is reduced. After increasing the cylinder diameter, the upward flow area expands, and the strong radial convergence at the exhaust pipe mouth has an impact on the upward flow, causing particles to escape by short-circuiting and at the same time also aggravating the escape of the particles held by the internal cyclone, and the amount of escape decreases with the increase of the cylinder diameter, and then increases, with the lowest at the optimal cylinder diameter. Increasing the cylinder diameter will make the exhaust pipe outside the formation of airflow barrier, particle short-circuit escape more difficult, but too much increase in the cylinder diameter will cause an increase in the short-circuit flow.

Positive charge modification of nanofiltration membrane surface is expected to improve lithium-magnesium separation selectivity, but conventional surface positive charge modification methods are inefficient, the positive charge density of the membrane surface is low, the electrostatic shielding effect is difficult to eliminate, and the improvement of lithium-magnesium selectivity is limited. In this study, polyethyleneimine (PEI) molecules rich in amine groups were grafted onto the surface of a commercial polyamide nanofiltration membrane, creating a surface-modified membrane (PEI/PA). The surface amine groups were then quaternized in situ through alkylation, producing a membrane with significantly enhanced positive charge (N-alkyl@PEI/PA). After modification, the isoelectric point of the membrane surface increased from 4.4 to 7.9, indicating a successful enhancement of surface charge. The performance of the modified membrane was further evaluated using a Li⁺/Mg²⁺ mixture with a concentration of 1000 mg·L^-1 and a mass ratio of 10∶1. The results showed that surface modification had minimal impact on membrane flux. At pH 6.8, its Li⁺/Mg²⁺ separation factor reached 35.7. At pH 9.7, the reduced protonation and weakened positive charge of the PEI/PA membrane led to a 72% decrease in lithium-magnesium selectivity, whereas the N-alkyl@PEI/PA membrane, with its higher positive charge, exhibited a smaller decline in performance, maintaining a separation factor of 21.9. This demonstrates the membrane’s potential for efficient Li⁺/Mg²⁺ separation across a broad pH range.

The development of carbon capture technology is crucial for mitigating global warming. Amine-based phase change absorbents are often used for chemical absorption of carbon dioxide due to their advantages such as low desorption energy consumption. However, the complexity of phase change absorbent formulations, unclear phase separation mechanisms, and high experimental costs limit the rapid development of novel high-performance phase change absorbents. To this end, this paper proposes a phase separation prediction methodology for amino-based phase change absorbents based on reaction templates and molecular dynamics. By constructing reaction templates, chemical absorption products are automatically generated. Molecular dynamic methods and indicators such as radial distribution functions are further employed to study the phase separation mechanisms of amino-based phase change absorbents and predict their phase separation behaviors. The proposed method is compiled into a fully automated software for predicting phase separation behaviors of phase change absorbents, complete with a visualization interface. This method has been applied to seven different phase change absorbent systems, with the predicted phase separation behaviors aligning with experimental results. It is also discovered that the hydrogen bonding interactions between organic solvents and water molecules are key factors influencing the phase separation behavior of phase change absorbents. The above studies assist in predicting the phase separation behavior of amino-based phase change absorbents from a computational perspective, which helps to reduce the cost of experimental testing and accelerate the development of novel high-performance phase change absorbents.

Membrane separation has emerged as a critical technology for treating oily wastewater due to its high efficiency, low energy consumption, and elimination of chemical additives. Polyethersulfone (PES) membranes are widely applied in wastewater treatment owing to their excellent thermal stability and mechanical strength. However, it is still a difficult problem to prepare PES membranes with high porosity sponge pore structure and stable super-hydrophilicity to achieve high-flux and anti-pollution separation of oily wastewater. Herein, we report the vapor-induced phase separation (VIPS) method for the fabrication of PES membranes with sponge-like pores and stable super-hydrophilicity, using PES as the matrix, polyvinylpyrrolidone (PVP) as a hydrophilic additive, and polyethylene glycol (PEG) as a pore-forming agent. At the same time, the PVP free radical cross-linking reaction in the membrane induced by Na₂S₂O₈ inhibited the dissolution and loss of PVP, so that the PES membrane maintained a long-term stable super-hydrophilic property and anti-oil pollution performance. The cross-linking of PVP effectively restrains the leaching of PVP during long-term use of the membranes. The PES membranes demonstrate an outstanding oil-in-water emulsion separation efficiency exceeding 99.8%, with a high water flux of 3900 L·m^-2·h^-1·bar^-1, and exhibits excellent cycle performance, with a flux attenuation rate as low as 5.4%, and a flux recovery rate of more than 96.3% after water washing.

Mixed matrix membranes based on metal organic frameworks (MOFs) have the performance advantages of both polymers and MOFs materials, and are research hotspot in the field of H₂/CO₂ gas separation. In this paper, CAU-1 with different particle sizes was dispersed into polyimide (PI) substrate by in-situ polymerization, and MOFs fillers and mixed matrix films were characterized by XRD, SEM, TG, FTIR, etc., to explore the effects of particle size and heat treatment temperature on H₂/CO₂ separation performance. The results showed that, compared with the pure polymer membrane, the separation effect of mixed matrix membrane was significantly improved. In-situ polymerization could significantly improve the interfacial compatibility of MOF and polymer, and the separation factor of H₂/CO₂ of PI/CAU-1 membrane after optimization of CAU-1 particle size and heat treatment temperature could reach 8.4.