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Membrane separation processes play a crucial role in gas separation applications, with the need for ongoing development to fulfill new needs for today's challenges. For this purpose, novel 2D nanomaterials are progressively showing promise over conventional polymer‐based membrane material, exhibiting excellent molecular transport properties. Beyond the 2D materials already studied in this field, this article presents the first gas separation performances of vanadium pentoxide membrane. Brand new in gas separation topic, 2D van der Waals nanoribbons of V2O5 are successfully synthesized and layered on an anodic aluminum oxide substrate. Gas permeation analysis of He, N2, and CO2 are performed on various membranes made from different quantities of the nanomaterial. Gas permeance results suggest a deviation from an expected Knudsen diffusion mechanism of the V2O5‐based membrane for He separation. The ideal selectivities of He/N2 and He/CO2 are compared to Robeson's upper bound for polymeric membranes. V2O5 membranes, prepared with the highest V2O5 quantity, exceeded the upper bound from 2008 for He/N2 and 2019 (the most recent) for He/CO2, demonstrating the interesting potential of V2O5 2D materials for gas separation. [ABSTRACT FROM AUTHOR]

The current state of reticular chemistry enables the synthesis of a wide range of highly porous nanomaterials for gas separation, including metal‐organic frameworks (MOFs), covalent organic frameworks (COFs), porous organic cages (POCs), metal‐organic cages (MOCs), and polyhedra (MOPs). This perspective focuses on membrane technology, a key player in energy‐efficient gas separations. It explores the world of reticular materials, taking a glance at tiny pore windows with narrow openings, which are ideal for high‐resolution molecular sieving, and how to design them. Promising concepts in this field are membranes consisting of neat materials, but also mixed matrix membranes, where polymeric films incorporate reticular fillers, creating cost‐efficient membranes. This article sheds light on the potential use of reticular materials as membrane components. The reticular synthesis of MOFs offers the ability to separate gas molecules with minimal size differences effectively. For COFs, the crucial factor lies in reducing their pore size, preferably through functional group modifications. Porous cage compounds can achieve fine distribution from homogeneous dispersions into polymers making them excellent candidates for mixed matrix membranes. This perspective provides strategies and guiding principles for the future of reticular nanomaterials‐based membranes, addressing the pressing need for advanced and efficient separation technologies. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are prized for their selective dissolution of carbon dioxide (CO2), leading to their widespread use in ionogel membranes for gas separation. Despite their advantages, creating sustainable ionogel membranes with high IL contents poses challenges due to limited mechanical strength, leakage risks, and poor recyclability. Herein, we leverage copolymerized and supramolecularly bound ILs to develop ionogel membranes with high mechanical strength, zero leakage, and excellent self‐healing and recycling capabilities. These membranes exhibit superior ideal selectivity for gas separation compared to other reported ionogel membranes, achieving a CO2/nitrogen selectivity of 61.7 and a CO2/methane selectivity of 24.6, coupled with an acceptable CO2 permeability of 186.4 Barrer. Additionally, these gas separation ionogel membranes can be upcycled into ionic skins for sensing applications, further enhancing their utility. This research outlines a strategic approach to molecularly engineer ionogel membranes, offering a promising pathway for developing sustainable, high‐performance materials for advanced gas separation technologies. [ABSTRACT FROM AUTHOR]

Biogas is a type of biomass energy source, primarily composed of methane and carbon dioxide. It is generated through the controlled anaerobic digestion of manure or other organic residues. As a cleaner alternative to conventional fuels, fully purified biogas can produce approximately 36.68 MJ/m3 of en.ergy. As the separation of CO2/CH4 in biogas became an important part of the energy industry, we used membrane separation technique to study its separation methods. At first, 3,3′‐dihydroxy‐4,4′‐diamino‐biphenyl (HAB) and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) were polymerized by open‐loop as polyamide acid macromolecules. Then it was divided into two research routes. One was condensation to polyimide (PI) membranes directly and then thermal rearrangement (TR); the other one was ionic liquid (IL) added before condensation and thermal rearrangement. Through adjusting the thermal rearrangement temperature, different modified polyimide membranes were obtained and tested their separation performance of CO2/CH4. For the result of the test, the best one, membrane HAB‐6FDA‐IL‐TR400, could reach a good separation performance as PCO2 = 403.80 Barrer, αCO2/CH4 = 82.35. It was beyond the Robeson's 2019 upper limit and proved that the modification by IL and thermal rearrangement was benefit for the separation performance of polyimide membranes. [ABSTRACT FROM AUTHOR]

Vapor phase infiltration (VPI) has emerged as a promising tool for fabrication of novel hybrid materials. In the field of polymeric gas separation membranes, a beneficial impact on stability and membrane performance is known for several polymers with differing functional groups. This study for the first time investigates VPI of trimethylaluminum (TMA) into poly(1‐trimethylsilyl‐1‐propyne) (PTMSP), featuring a carbon–carbon double bond as functional group. Saturation of the precursor inside the polymer is already attained after 60 s infiltration time leading to significant densification of the material. Depth profiling proves accumulation of aluminum in the polymer itself, but a significantly increased accumulation is visible in the gradient layer between polymer and SiO2 substrate. A reaction pathway is proposed and supplemented by density‐functional theory (DFT) calculations. Infrared spectra derived from both experiments and simulation support the presented reaction pathway. In terms of permeance, a favorable impact on selectivity is observed for infiltration times up to 1 s. Longer infiltration times yield greatly reduced permeance values close or even below the detection limit of the measurement device. The present results of this study set a strong basis for the application of VPI on polymers for gas‐barrier and membrane applications in the future. [ABSTRACT FROM AUTHOR]

This study explores fabrication and characterization of mixed matrix membranes (MMMs) for gas separation, employing a cost‐effective solution casting method. Polycarbonate (PC) and polystyrene (PS) blends are combined with graphene oxide (GO) and zirconium dioxide (ZrO2) nanofillers, with and without a deep eutectic solvent (DES) obtained through hydrogen bond exchange. Various MMMs compositions (2–20 wt%) are systematically examined using diverse characterization techniques, including differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, porosity determination, and water contact angle analysis. The MMMs exhibit enhanced gas permeability and selectivity, surpassing conventional membrane materials. Notably, H2 gas permeability reaches outstanding levels, with the composition PC/PS‐DES‐GO/ZrO2 at 20 wt% (PBC20‐IV) demonstrating the highest value of 86.32 Barrer. This superior performance is attributed to the unique properties of ZrO2, increased sorption capacity of GO, and enhanced thermal stability due to DES. Permeability data for CO2, N2, O2, and CH4 also show significant values, aligning with the observed trends in H2 permeability. Robeson's plot for the H2/CO2 gas pair surpasses the 2008 upper bound, placing the MMMs in a novel category for gas separation membranes. The incorporation of DES‐modified nanofiller blend composites presents a promising strategy for the potential production of pure hydrogen. [ABSTRACT FROM AUTHOR]

The majority of materials used for membrane-based separation of gas mixtures are non-renewable and non-biodegradable, and the assessment of alternative bio-based polymers requires expensive and time-consuming experimental campaigns. This effort can be reduced by adopting suitable modelling approaches. In this series of works, we propose various modelling approaches to assess the CO2/CH4 separation performance of eight different copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV) using a limited amount of experimental data for model calibration. In part 1, we adopted a fully atomistic approach based on Molecular Dynamics (MD), while, in this work, we propose a multiscale methodology where a molecular description of the polymers is bridged to a macroscopic prediction of its gas sorption behaviour. PHBV structures were simulated using MD to obtain pressure–volume–temperature data, which were used to parametrise the Sanchez–Lacombe Equation of State. This, in turn, allows for the evaluation of the CO2 and CH4 solubility in the copolymers at various pressures and compositions with little computational effort, enabling the estimate of the sorption-based selectivity. The gas separation performance obtained with this multiscale technique was compared to results obtained with a fully atomistic model and experimental data. The solubility–selectivity for the CO2/CH4 mixture is in reasonable agreement between the two models and the experimental data. The multiscale method presented is a time-efficient alternative to fully atomistic methods and detailed experimental campaigns and can accelerate the introduction of renewable materials in different applications. [ABSTRACT FROM AUTHOR]

Polymer-based membrane separation technology is gaining popularity due to its cost-effectiveness and operational simplicity. Cellulose acetate (CA) stands out as an attractive biobased polymer for membrane applications due to its remarkable mechanical properties and ease of manufacturing. To improve the selectivity of CA-based membranes for carbon dioxide (CO2) separation, the incorporation of polyethylene glycol methyl ether acrylate (PEGMEA), known for its CO2 absorption properties, has emerged as a promising approach for creating high-performance membrane materials with low operating pressure. This study provides insight into the production of PEGMEA-grafted CA membranes via gamma radiation and their performance for CO2/CH4 gas separation. CO2 permeation of the obtained CA-PEGMEA membranes was successfully improved and achieved the desired selectivity for CO2/CH4 separation. A comprehensive study of the membrane properties was conducted, encompassing structural characterization, surface analysis, permeability, selectivity, thermal analysis, and crystallinity, which are essential for understanding and assessing the membrane's performance. This work emphasizes gamma radiation graft polymerization and shows its applicability for high-performance gas separation membrane materials. [ABSTRACT FROM AUTHOR]

Given that SOF materials have both inorganic and organic properties and are easy to prepare and structurally designable, this paper carries out the microbehavioral analysis and membrane design of SOF-8, SOF-9, and SOF-10 membranes for the hydrogen purification process of RMFCs. Since three materials have complementary performance characteristics for hydrogen purification, this paper focuses on the gas separation behavior of these three composite membranes using molecular dynamics simulations. Results showed that the SOF-9a+10a composite membranes could 100% block CO 2 and CO, and displayed an excellent H 2 permeability of 6.118 × 105 GPU during H 2 /CO 2 separation, which exceeded the industry standard by nearly 105 times. Additionally, the SOF-9a+8 and SOF-10a+8 composite membranes improved gas selectivity and maintained high H 2 permeability. Moreover, microdiffusion analyses revealed that the small pore sizes and irregular-shaped pore channels effectively hindered CO 2 and CO transport. Microscopic analysis shows the potential of SOF composite membranes for gas separation. [Display omitted] • SOF composite membranes can effectively improve gas selectivity. • Small pore sizes and irregular pore channels can effectively block CO 2 transport. • SOF-9a+10 can 100% intercept CO 2 and CO. • The interaction between gas and membrane affects the gas separation performance. [ABSTRACT FROM AUTHOR]

A fluorescein‐based diamine, 2‐(3,6‐bis(4‐amino‐3‐hydroxyphenoxy)‐9H‐xanthen‐9‐yl) benzoic acid (CADA), was synthesized and copolymerized with Durene and 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) to form a 6FDA‐Durene/CADA (3:2) copolyimide. The copolyimide was thermally cross‐linked at 300–425°C to form a series of decarboxylated cross‐linked polyimides. Compared with the 6FDA‐CADA polyimide, the incorporation of Durene diamine increased gas permeability of the pristine and the thermally cross‐linked polyimides greatly. The copolyimide cross‐linked at 375°C showed separation performance to the O2/N2 gas pair beyond the 1991 Robeson upper limit, while the CO2/CH4 separation property of the copolyimide cross‐linked at 425°C (PI‐425) was close to the 2008 Robeson upper limit. Moreover, the anti‐CO2‐induced plasticization property of the 6FDA‐Durene/CADA(3:2) copolyimides was improved by cross‐linking. The copolyimides cross‐linked at 350°C and above were not plasticized at a CO2 pressure up to 30 atm. This study showed that gas transport property of the decarboxylated cross‐linked polyimides could be improved significantly by the incorporation of bulky diamino moiety. The fluorescein‐based copolyimide had great potentials for gas separation applications. [ABSTRACT FROM AUTHOR]

Membrane gas separation is an environmentally friendly and economical method used to separate valuable gases, industrial process gas wastes, and carbon dioxide from mixed gases. The most important part of this method is the membranes. Gas separation membranes are expected to have high separation and permeability performance, high mechanical strength, easy and fast production capability, and low prices. Polymer-based membranes are mostly preferred depending on the ease of modification capability. In this study, a zirconium-based metal organic framework (Zr-MOF, MIL-140 A) was synthesized and used as a filler within polyvinyl alcohol (PVA) matrix for the selective separation of hydrogen (H2) from carbon dioxide (CO2). The effect of MIL-140 A addition on the mechanical, structural, and morphological properties of PVA was evaluated. The MIL-140 A significantly improved the mechanical strength of the membrane. According to the gas separation results, the increasing concentration of MIL-140 A increased the selective separation performance of the nanocomposite membrane. The highest mechanical strength (43.1 MPa) and best film-forming ability were obtained with 3 wt% MIL-140 A loaded membrane. The ideal H2/CO2 selectivity and hydrogen permeability were obtained as 5.6 and 944 Barrer, respectively at 2 bar feed pressure and room temperature. The highest ideal H2/CO2 selectivity was obtained as 6.3 with the H2 permeability of 959 Barrer when the MIL-140 A ratio was 4 wt%. [ABSTRACT FROM AUTHOR]

The presented work aims to study the gas transport characteristics of polymeric hollowfiber gas separation membranes. The study focused on examining the gas transport characteristics of polymeric hollow-fiber gas separation membranes using materials such as polysulfone (PSF), polyphenylene oxide (PPO), polyetherimide (PEI), and polyetherimide with polyimide (PEI+PI) for the separation of air mixtures. The permeance values of pure gases O2 and N2and the mixed permeances of oxygen and nitrogen during air separation were obtained. Membrane permeance was measured using an analytical setup combined with a mass spectrometer on membrane modules with different effective membrane areas. Mathematical models of the gas separation process built because of these values show significant discrepancies. To obtain a gas mixture with 95 mol.% nitrogen from the air, considering the mixture permeance, 15.8% more PSF membrane area is required than considering the permeance of pure gases. For a PPO membrane, this value is 13.9%; for PEI, 19.8% less area is required, and for PEI+PI, 15.9% less. In the design of industrial or semiindustrial membrane installations, such discrepancies can lead to significant technical and economic errors. [ABSTRACT FROM AUTHOR]

In a previous study, we demonstrated a change in membrane morphology and gas separation performance by varying the recipe of a casting solution based on polysulfone in a certain solvent system. Although all results were reproducible, all used solvents were harmful and not sustainable. In this study, the solvents tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc) are replaced by the more sustainable solvents 2-methyl-tetrahydrofuran (2M-THF), N-butyl pyrrolidinone (NBP) and cyclopentyl methyl ether (CPME). The gas permeation performance and, for the first time, morphology of the membranes before and after solvent replacement were determined and compared by single gas permeation measurements and SEM microscopy. It is shown that THF can be replaced by 2M-THF and NBP without decreasing the gas permeation performance. With CPME replacing THF, no membranes were formed. Systems with 2M-THF as a THF alternative showed the best gas permeation results. Permeances for the tested gases oxygen (O2), nitrogen (N2), carbon dioxide (CO2) and methane (CH4) were 5.91 × 10−2, 8.84 × 10−3, 4.00 × 10−1 and 1.00 × 10−2 GPU, respectively. Permselectivities of those membranes for the gas pairs O2/N2, CO2/N2 and CO2/CH4 were 6.7, 38.3 and 34.0, respectively. When also replacing DMAc in the solvent system, no or only porous membranes were obtained, even if the precipitation procedure was adjusted. These findings indicate that a complete replacement of the solvent system without affecting the membrane morphology or gas permeation performance is not possible. By varying the temperature of the precipitation bath, the formation of mechanically stable PSU membranes is possible only if THF is replaced by 2M-THF. [ABSTRACT FROM AUTHOR]

The Robeson bound is a theoretical limit that applies to kinetics-driven membrane separations of gas mixtures. However, this bound does not apply to sorption-driven membrane processes such as CO2/N2 separation, which lacks a theoretical explanation. As a result, we are uncertain about the factors that control the limiting behavior of sorption-driven separations. To address this issue, we employed a simple lattice model and dynamic mean field theory to examine the transport properties of disordered model structures, isolating sorption effects from purely kinetic effects. Our findings indicate that transport effects play a crucial role in sorption-driven processes, and perm-selectivity is consistently lower than sorption selectivity, which is an unattainable limit. We used basic geometric fragments of the structure to explain how transport effects emerge and manifest themselves in sorption-driven processes. [ABSTRACT FROM AUTHOR]

The membrane technology has been receiving significant interest in both research and industrial applications, particularly in the separation of CO2/CH4. These methods, as published, aim to overcome the limitations of pure polymeric membranes and offer an alternative approach in separation techniques where membrane technology can overcome the constraints of conventional methods such as Solid Phase Extraction (SPE) and Liquid-Liquid Extraction (LLE). Fabricating membranes using fillers as adsorbents can enhance membrane separation performance due to their porous nature. Hence, the selection of suitable fillers is crucial to maximize membrane efficiency in separating analytes. This paper will review 3 types of fillers-metal-organic frameworks, carbonaceous nanomaterials and mesoporous molecular sieves-from various research papers published in recent years. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) are promising porous materials that have huge potential for gas separation when put in the membrane configuration. MOFs have huge potential due to certain salient features of the MOFs such as excellent pore size, ease of tuning the pore chemistry, higher surface area, and chemical and thermal stabilities. MOFs have been explored for various gas separation and storage applications. This review discusses various approaches for fabricating MOFs‐based membranes for the separation of H2 gas from a variety of feeds having various gases CO2, CO, N2, and CH4 as impurities. The emphasis has been put on three types of membranes for H2 separation which include MOFs‐based hollow fibrous/tubular/disk membranes, MOFs‐based mixed matrix membranes (MMMs), and MOFs‐based stand‐alone membranes. In addition, various challenges such as reducing inhomogeneity between MOFs and polymeric matrices have also been discussed. Similarly, the approaches to successfully decorating MOFs on different supports in different configurations have been explained. The possible ways of improving the MOFs‐based membranes for H2 have also been discussed. [ABSTRACT FROM AUTHOR]

Separating helium (He) and hydrogen (H2), two gases that are extremely similar in molecular size and condensation properties, presents a formidable challenge in the helium industry. The development of membranes capable of precisely differentiating between these gases is crucial for achieving large‐scale, energy‐efficient He/H2 separation. However, the limited selectivity of current membranes has hindered their practical application. In this study, we propose a novel approach to overcome this challenge by engineering submicroporous membranes through the fluorination of partially carbonized hollow fibers. We demonstrate that the fluorine substitution on the inner rim of the micropore walls within the carbon hollow fibers enables tunability of the microporous architecture. Furthermore, it enhances interactions between H2 molecules and the micropore walls through the polarization and hydrogen bonding induced by C−F bonds, resulting in simultaneous improvements in both He/H2 diffusivity and solubility selectivities. The fluorinated HFM‐550‐F‐1 min membrane exhibits exceptional mixed‐gas separation performance, with a binary mixed‐gas He/H2 selectivity of 10.5 and a ternary mixed‐gas He/(H2+CO2) selectivity of 20.8, at 40 bar feed pressure and 35 °C, surpassing all previously reported polymer‐based gas separation membranes, and remarkable plasticization resistance and long‐term continuous stability over 30 days. [ABSTRACT FROM AUTHOR]

Membrane-based gas separation, characterized by a small footprint, low energy consumption and no pollution, has gained widespread attention as an environmentally friendly alternative to traditional gas separation. Metal–organic-frameworks (MOFs) are considered to be one of the most promising membrane-based gas separation materials because of their large specific surface area and high porosity. One of the hottest studies at the moment is how to utilize the characteristics of MOFs to prepare higher performance gas separation membranes. This paper provides a review of gas separation membranes used in recent years. Firstly, the synthesis methods of MOFs and MOF membranes are briefly introduced. Then, methods to improve the membrane properties of MOFs are described in detail, and include applications of lamellar MOFs, ionic liquid (IL) spin coating, functionalization of MOFs, defect engineering and mixed fillers. In addition, the challenges of MOF-based gas separation membranes are presented, including pore size, environmental disturbances, plasticization, interfacial compatibility, and so on. Finally, based on the current development status of the MOF membranes, the development prospects of MOF gas separation membranes are discussed. It is hoped to provide reliable and complete ideas for researchers to prepare high-performance gas separation membranes in the future. [ABSTRACT FROM AUTHOR]

Development of high-performance CO2 separation membrane materials is the most vital challenge in membrane separation technology for carbon emission reduction and carbon neutrality. Mixed matrix membranes (MMMs) were prepared using polyether-block-polyamide (Pebax-1074) as the membrane matrix and multi-walled carbon nanotubes (MWCNTs) as the filler. The morphology, microstructure, surface functional groups, and thermal properties of the MMMs were characterized by scanning electron microscope, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis, respectively. The effects of MWCNTs content, permeation temperature, and permeation pressure on the microstructure and gas separation properties of the prepared MMMs were investigated. The results show that the microstructure and the gas separation performance of the membrane can be significantly regulated through varying the content of MWCNTs. The optimal separation performance is attained to 291.4 Barrer of CO2 permeability and 160.2 of CO2/N2 selectivity for the MMMs containing 12% MWCNTs under the condition of 30 °C and 0.2 MPa. The exceptional separation performance is far beyond the commercially attractive Robeson upper-bound. [ABSTRACT FROM AUTHOR]

Defect‐engineered metal–organic frameworks (MOFs) with outstanding structural and chemical features have become excellent candidates for specific separation applications. The introduction of structural defects in MOFs as an efficient approach to manipulate their functionality provides excellent opportunities for the preparation of MOF‐based mixed matrix membranes (MMMs). However, the use of this strategy to adjust the properties and develop the separation performance of gas separation membranes is still in its early stages. Here, a novel defect‐engineered MOF (quasi ZrFum or Q‐ZrFum) was synthesized via a controlled thermal deligandation process and incorporated into a CO2‐philic 6FDA‐durene polyimide (PI) matrix to form Q‐ZrFum loaded MMMs. Defect‐engineered MOFs and fabricated MMMs were investigated regarding their characteristic properties and separation performance. The incorporation of defects into the MOF structure increases the pore size and provides unsaturated active metal sites that positively affect CO2 molecule transport. The interfacial compatibility between the Q‐ZrFum particles and the PI matrix increases via the deligandation process, which improves the mechanical strength of Q‐ZrFum loaded membranes. MMM containing 5 wt.% of defect‐engineered Q‐ZrFum exhibits excellent CO2 permeability of 1308 Barrer, which increased by 99 % compared to the pure PI membrane (656 Barrer) at a feed pressure of 2 bar. CO2/CH4 and CO2/N2 selectivity reached 44 and 26.6 which increased by about 70 and 16 %, respectively. This study emphasizes that defect‐engineered MOFs can be promising candidates for use as fillers in the preparation of MMMs for the future development of membrane‐based gas separation applications. [ABSTRACT FROM AUTHOR]

In the portfolio of technologies available for net zero-enabling solutions, such as carbon capture and low-carbon production of hydrogen, membrane-based gas separation is a sustainable alternative to energy-intensive processes, such as solvent-based absorption or cryogenic distillation. Detailed knowledge of membrane materials performance in wide operative ranges is a necessary prerequisite for the design of efficient membrane processes. With the increasing popularization of data-driven methods in natural sciences and engineering, the investigation of their potential to support materials and process design for gas separation with membranes has received increasing attention, as it can help compact the lab-to-market cycle. In this work we review several machine learning (ML) strategies for the estimation of the gas separation performance of polymer membranes. New hybrid modelling strategies, in which ML complements physics-based models and simulation methods, are also discussed. Such strategies can enable the fast screening of large databases of existing materials for a specific separation, as well as assist in de-novo materials design. We conclude by highlighting the challenges and future directions envisioned for the ML-assisted design and optimization of membrane materials and processes for traditional, as well as new, membrane separations. [ABSTRACT FROM AUTHOR]

The novel mixed-matrix membranes that are designed to simultaneously enhance gas permeability, selectivity and filler–polymer compatibility are highly sought for industrial deployment of membrane technology for large-scale CO2 capture. Carbon capture performance of polymeric membranes is significantly improved by doping mesoporous zeolitic imidazolate framework (ZIF-L) nanoflakes into polymer matrix. ZIF-L is prepared via cold-synthesis method and is incorporated in varied concentrations into polyethersulfone (PES) matrix to improve CO2 permeability and CO2/N2 selectivity of resultant membranes. Morphological and structural characteristics of synthesized ZIF-L nanoparticles are characterized by SEM and XRD, respectively. Flat-sheet membranes prepared through phase inversion method are characterized to evaluating their structural, crystalline, morphological and thermal properties by FTIR, XRD, SEM and TGA techniques. Characterizations indicated homogeneous dispersal of nanofillers along strong interactions between ZIF-L to polymer chains which enhanced the carbon capture efficiency of membranes and measured as CO2 permeability and CO2/N2 selectivity by gas permeation test under different feed-side upstream pressures. Both filler concentration and feed pressure led to enhanced permeation through membranes in comparison with pristine PES membrane, and CO2 permeability increased from 3.7 to 24.9 Barrer for 3% ZIF-L nanoflakes doping while CO2/N2 selectivity is increased from 2.2 to 30.6 for 2% filler loading at 1.5 bar pressure. Raising feed pressure from 1.5 to 6 bar is resulted into CO2 permeability increment from 24.9 to 27.2 Barrer for 3% filler loading. Therefore, these designed membranes have efficacy for permeability for CO2 and N2 in industrial applications and environmental solutions. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is ideal for making powerful, high-frequency chips for 5 G and electric vehicles due to its wide band gap and resistance to high voltage. However, its powerful chemical bond strength and extreme hardness make it difficult for die separation in the post-wafer process. A hybrid process technology is proposed, where die scribing is performed on SiC wafer using a femtosecond pulsed laser-assisted ablation. The extremely short energy pulses forced the ablation of traces of SiC at extreme speed, breaking chemical bonds and thereby reducing strength and hardness for easy high-speed cutting along the scribed lanes with a polycrystalline diamond wheel. The experiment showed that the average stage current dropped from 0.90 A to 0.45 A and kerf chipping ratio from 11.7 to 4.1 during die separation, proving that the process removed materials along the separation lanes using a wheel tool at low grinding force, creating separation lanes of outstanding straightness and minimal kerf chippings and SiC dies of high integrity. Furthermore, thanks to the on-line rotational machining and dressing of the wheel tool, the blunt diamond abrasive cutting edge could be redressed to expose chip pockets of appropriate depth and protruding grinding edges with a favorable negative rake angle. The established grinding regime utilizing a pressure-grinding force in cutting and material removal reduced cracking at the SiC surface. In this paper, the laser energy density, scanning speed, number of ablations, focus position, as well as the speed, feed-rate and grinding depth of the wheel tool are also discussed in detail. [ABSTRACT FROM AUTHOR]

Polymeric membranes have emerged as a competitive technology in gas separation processes due to their notable energy efficiency, environmentally friendly attributes and minimal system footprint. To enhance the performance of conventional polymeric membranes, significant research efforts have been dedicated to modifying their surface properties in the last decade. Among the various techniques explored, membrane surface modification using coating methods, such as dip-coating, spray-coating, grafting and interfacial polymerization stands out as one of the most popular and straightforward approaches. Scientists have utilized a diverse array of coating solutions comprising either polymeric materials or hybrid materials in these methods, yielding promising outcomes. This article aims to present a comprehensive review of the advancements made in surface coating approaches employed for modifying hollow fiber membrane surfaces over the past decade. The review encompasses an evaluation of how different coating approaches and solutions affect the surface's physicochemical properties and the gas separation performance of the membranes. Furthermore, the article delves into discussing technical challenges associated with these surface coating approaches, providing an insightful analysis. Lastly, the review concludes by outlining perspectives and recommending future research directions for this area of study, highlighting the potential avenues for innovation and advancement in surface-coated hollow fiber membranes for gas separation applications. [ABSTRACT FROM AUTHOR]

How defects between layers of porous membranes affect their gas separation performance is still a problem. Here, we design three bilayer porous graphene membranes with different and representative defect torsion angles to regulate gas separation. We find from first-principles density functional theory calculations that the selectivity of the H 2 /CH 4 mixture can be varied by several orders of magnitude, of about 107:1 (E barrier/CH4 : 0.24, 0.18, 0.24 eV), 1019:1 (E barrier/CH4 : 0.49, 0.37, 0.47 eV) and 1012:1 (E barrier/CH4 : 0.42, 0.15, 0.45 eV), when going through the models of bi-H pore10 -20 x , bi-H pore10 -20 y and bi-H pore10 -47 y. Every barrier curve of gas penetration features three peaks. Additionally, molecular dynamics simulations show that the bilayer porous graphene membrane with a defect torsion angle of 20° along the x / y -axis possesses high H 2 /CH 4 separation ratio (up to 56–58:1) at room temperature after 5000 ps. The defect torsion angle of bilayer porous graphene improves the selectivity exponentially by regulating the three high penetration energy barriers of CH 4 , while the three energy barriers of H 2 are all very low. This work provides a new strategy to achieve highly selective separation of mixture by porous 2D-materials via regulating defect torsion angle between layers. [Display omitted] • The defect torsion angle is a powerful knob for regulating gas separation. • The potential energy curve for defect torsion angle model features three peaks. • Bi-H pore10 -20 y shows a high separation selectivity of 1019:1 for H 2 over CH 4. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF)‐based mixed matrix membranes (MMMs) have shown great promises to overcome the performance upper limit of polymeric membranes for various gas separation processes. However, the gas separation properties of the MMMs largely depend on the MOF‐polymer interfacial compatibility which is a metric difficult to quantify. In most cases, whether a MOF filler and a polymer matrix make a good pair is not revealed until the gas transport experiments are performed. This is because there is a lack of characterization techniques to directly probe the MOF‐polymer interfacial compatibility. In this work, we demonstrate a self‐sorting method to rank the interface compatibility among several MOF‐polymer pairs. By mixing one MOF with two polymers in an MMM, the demixing of two polymers will form two polymer domains. The MOF particles will preferably partition into the "preferred" polymer domain due to their higher interfacial affinity. By scanning different polymer pairs, a rank of MOF‐polymer interfacial compatibility from high to low can be obtained. Moreover, based on this ranking, it was also found that a highly compatible MOF‐polymer pair suggested by this method also corresponds to a more predictable MMM gas separation performance. [ABSTRACT FROM AUTHOR]

This paper presents a flexible family of 2- and 3-parameter distributions whose support is the closed interval [0,1], with explicit density, cumulative density, and quantile functions. These distributions are suited to modeling quantiles, thereby expanding the toolbox of distributions for doubly-bounded random variables. The densities at the boundaries are determined by dispersion and skew parameters, and a third parameter exclusively influences location. The paper also discusses practical issues of parameter estimation and assesses estimation bias, Type I error-rate accuracy, and parameter-estimate collinearity. It also provides three examples of applications to real data using new packages implementing the distributions in R and Stata. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is a greenhouse gas which is mainly found in natural gas (NG), biogas, and flue gas. Anthropogenic CO2 emissions are the direct result of burning fossil fuels. Meanwhile, pre‐ and postcombustion CO2 separation is a current state of CO2 removal method in an extensive manner. From environmental, economic, and transportation perspectives, removal of CO2 has driven the development of its separation process technology. Among the reported technologies, membrane‐based gas separation technologies have grown substantially, breakthroughs and advances in past decades. This review paper aims to provide an overview on competitive gas separation processes, different types of membranes available, gas transport mechanisms, and fabrication process of hollow fiber membranes, particularly dual‐layer hollow fiber membrane. The performance of the membranes in CO2 separation and effect of spinning parameters on the formation of hollow fiber membranes are highlighted. In addition, approaches to improve the dual‐layer adhesion, strategies to enhance the filler compatibility in the development of dual‐layer hollow fiber mixed‐matrix membranes, and effect of post‐treatments on the gas separation performance of membrane are also discussed. Finally, challenges and future perspectives of dual‐layer hollow fiber mixed‐matrix membranes toward CO2 capture, particularly on CO2/CH4 and CO2/N2 separation, are also included, due to its substantial and direct relevance to the gas separation industry. [ABSTRACT FROM AUTHOR]

Abstract The interaction of rarefied gases with functionalized surfaces is of great importance in technical applications such as gas separation membranes and catalysis. To investigate the influence of functionalization and rarefaction on gas flow rate in a defined geometry, pressure-driven gas flow experiments with helium and carbon dioxide through plain and alkyl-functionalized microchannels are performed. The experiments cover Knudsen numbers from 0.01 to 200 and therefore the slip flow regime up to free molecular flow. To minimize the experimental uncertainty which is prevalent in micro flow experiments, a methodology is developed to make optimal use of the measurement data. The results are compared to an analysis-based hydraulic closure model (ACM) predicting rarefied gas flow in straight channels and to numerical solutions of the linearized S-model and BGK kinetic equations. The experimental data shows that if there is a difference between plain and functionalized channels, it is likely obscured by experimental uncertainty. This stands in contrast to previous measurements in smaller geometries and demonstrates that the surface-to-volume ratio of 0.4 $$\upmu$$ μ m $$^{-1}$$ - 1 seems to be too small for the functionalization to have a strong influence and highlights the importance of geometric scale for surface effects. These results also shed light on the molecular reflection characteristics described by the TMAC.

The fabrication of membranes for gas separation presents challenges that hinder their deployment as a truly sustainable technology. This review systematically explores the evolution and advancements in materials and manufacturing methods of polymer-based membranes, with a keen emphasis on sustainability and efficiency. The review delineates a broad spectrum of manufacturing techniques, ranging from traditional methods to cutting-edge approaches such as layer-by-layer assembly, and green synthesis, highlighting their implications for environmental sustainability, performance enhancement, scalability, and economic viability. Key findings indicate a significant shift towards greener solvents, bio-based polymers and processes that reduce waste and costs. Critical analysis uncovers a growing focus on understanding the life cycle of membranes and developing strategies for end-of-life such as recycling and the use of biodegradable materials, underscoring the commitment of the community to minimizing environmental footprints. [ABSTRACT FROM AUTHOR]

The efficacy of the fungicide pydiflumetofen + difenoconazole (Postiva) was evaluated at varying application rates and intervals to control black spot disease (Diplocarpon rosae) in rose (Rosa spp. ‘Coral Drift’). Container-grown roses were arranged in a completely randomized design with five single-plant replications. Experiments were conducted under greenhouse and shade-house conditions (56% shade) in 2021/2022 and 2023. Black spot disease in roses was developed naturally. Pydiflumetofen + difenoconazole at 1.1, 1.6, and 2.2 mL·L–1, and standard fungicide azoxystrobin + benzovindiflupyr (Mural) at 0.5·g L–1 were sprayed on foliage to runoff on a 2- or 4-week interval. Plants that were not treated with fungicide served as the controls. Plants were evaluated weekly for disease severity (0%–100% foliage affected) and defoliation (0%–100% defoliation). The season-long area under the disease progress curve (AUDPC) and area under the defoliation progress curve (AUDFC) were calculated for the evaluation period. Pydiflumetofen + difenoconazole reduced significantly black spot disease severity, AUDPC, defoliation, and AUDFC both in greenhouse and shade-house conditions compared with control plants, and was as effective as azoxystrobin + benzovindiflupyr. All the application rates and intervals of pydiflumetofen + difenoconazole were equally effective in reducing black spot severity and AUDPC. Our findings suggest that pydiflumetofen + difenoconazole at the lowest rate with the longest application interval is the most cost-effective, and has similar efficacy as treatments with higher rates and more frequent intervals. [ABSTRACT FROM AUTHOR]

This work aims to expand the structure–property relationships of bromo-containing polyimides and the influence of bromine atoms on the gas separation properties of such materials. A series of intrinsically microporous polyimides were synthesized from 2,2′-dibromo-4,4′,5,5′-bipohenyltetracarboxylic dianhydride (Br-BPDA) and five bulky diamines, (7,7′-(mesitylmethylene)bis(8-methyldibenzo[b,e][1,4]dioxin-2-amine) (MMBMA), 7,7′-(Mesitylmethylene)bis(1,8-dimethyldibenzo[b,e][1,4] dioxin-2-amine) (MMBDA), 4,10-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diamine (TBDA1), 4,10-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-3,9-diamine (TBDA2), and (9R,10R)-9,10-dihydro-9,10-[1,2]benzenoanthracene-2,6-diamine (DAT). The Br-BPDA-derived polyimides exhibited excellent solubility, high thermal stability, and good mechanical properties, with their tensile strength and modulus being 59.2–109.3 MPa and 1.8–2.2 GPa, respectively. The fractional free volumes (FFVs) and surface areas (SBET) of the Br-BPDA-derived polyimides were in the range of 0.169–0.216 and 211–342 m2 g−1, following the order of MMBDA > MMBMA > TBDA2 > DAT > TBDA1, wherein the Br-BPDA-MMBDA exhibited the highest SBET and FFV and thus highest CO2 permeability of 724.5 Barrer. Moreover, Br-BPDA-DAT displayed the best gas separation performance, with CO2, H2, O2, N2, and CH4 permeabilities of 349.8, 384.4, 69.8, 16.3, and 19.7 Barrer, and H2/N2 selectivity of 21.4. This can be ascribed to the ultra-micropores (<0.7 nm) caused by the high rigidity of Br-BPDA-DAT. In addition, all the bromo-containing polymers of intrinsic microporosity membranes exhibited excellent resistance to physical ageing. [ABSTRACT FROM AUTHOR]

A series of fluorinated co-polyimide films based on the 6FDA-FTPPA/BAFL backbone were prepared from 4-(3-fluoro-4- (trifluoromethyl)phenyl)-2,6-bis(4-aminophenyl)pyridine (FTPPA), commercial 9,9-bis(4-aminophenyl)fluorene (BAFL), and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), with varying ratios of FTPPA:BAFL units (3:1, 2:1, 1:1, 1: 2, and 1:3). Co-polyimides not only exhibit high thermal stability (Tg > 357°C), good optical properties (λcutoff > 327 nm) and hydrophobicity (contact angle >91.4°), but also favorable solubility properties in both high and low boiling organic solvents. The fractional free volume of the polymers was simulated using molecular mechanics and molecular dynamics and correlated with experimental gas separation data. The presence of bulky groups led to high FFVs (>17.8%) and the formation of large microcavities with diameters ranging from 5.48 to 5.72 A°, which efficiently increased gas permeability. In pure gas permeation experiments, the permeability coefficients of CO2 and He for the 6FDA-FTPPA/BAFL (3:1) film were 41.48 and 79.38 bar, respectively, which were superior to those of commercial Matrimid and Kapton in terms of gas permeability. In especial, the 6FDA-FTPPA/BAFL (1:2) and 6FDA-FTPPA/BAFL (1:3) in copolyimide membranes exhibited the most attractive separation performance for O2/N2 gas pairs, approaching the 1991 Roberson upper limit. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) could combine the advantages of both polymeric membranes and porous fillers, making them an effective alternative to conventional polymer membranes. However, interfacial incompatibility issues, such as the presence of interfacial voids, hardening of polymer chains, and blockage of micropores by polymers between common MMMs fillers and the polymer matrix, currently limit the gas separation performance of MMMs. Ternary phase MMMs (consisting of a filler, an additive, and a matrix) made by adding a third compound, usually functionalized additives, can overcome the structural problems of binary phase MMMs and positively impact membrane separation performance. This review introduces the structure and fabrication processes for ternary MMMs, categorizes various nanofillers and the third component, and summarizes and analyzes in detail the CO2 separation performance of newly developed ternary MMMs based on both rubbery and glassy polymers. Based on this separation data, the challenges of ternary MMMs are also discussed. Finally, future directions for ternary MMMs are proposed. [ABSTRACT FROM AUTHOR]

Using porous materials to selectively adsorb H2O from natural gas is a promising method to dehydrate methane (CH4). The structure of a Zirconium metal‐organic framework (Zr‐MOF), namely, MIP‐202, features a high density of amino groups, which can produce strong hydrogen bonding with H2O molecules. MIP‐202 is cost‐effective, green and scalable, and it exhibits good chemical stability under various conditions. This work incorporated MIP‐202 nanoparticles into the high permeability polymer polyetherimide (PEI), and the obtained Mixed Matrix Membranes (MMMs) was used for the gas separation of H2O/CH4. It is found that MMMs loaded with 20 wt% of MIP‐202 demonstrated a high H2O/CH4 selectivity of 832.2, which was about 760 times of that of the pure PEI. This approach offers a new route to fabricate functional membranes for energy‐efficient gas separations. [ABSTRACT FROM AUTHOR]

The interaction of rarefied gases with functionalized surfaces is of great importance in technical applications such as gas separation membranes and catalysis. To investigate the influence of functionalization and rarefaction on gas flow rate in a defined geometry, pressure-driven gas flow experiments with helium and carbon dioxide through plain and alkyl-functionalized microchannels are performed. The experiments cover Knudsen numbers from 0.01 to 200 and therefore the slip flow regime up to free molecular flow. To minimize the experimental uncertainty which is prevalent in micro flow experiments, a methodology is developed to make optimal use of the measurement data. The results are compared to an analysis-based hydraulic closure model (ACM) predicting rarefied gas flow in straight channels and to numerical solutions of the linearized S-model and BGK kinetic equations. The experimental data shows that if there is a difference between plain and functionalized channels, it is likely obscured by experimental uncertainty. This stands in contrast to previous measurements in smaller geometries and demonstrates that the surface-to-volume ratio of 0.4 μ m - 1 seems to be too small for the functionalization to have a strong influence and highlights the importance of geometric scale for surface effects. These results also shed light on the molecular reflection characteristics described by the TMAC. [ABSTRACT FROM AUTHOR]

The advent of two-dimensional nanomaterials, a revolutionary class of materials, is marked by their atomic-scale thickness, superior aspect ratios, robust mechanical attributes, and exceptional chemical stability. These materials, producible on a large scale, are emerging as the forefront candidates in the domain of membrane-based gas separation. The concept of defect engineering in 2D nanomaterials has introduced a novel approach in their application for membrane separation, offering an effective technique to augment the performance of these membranes. Nonetheless, the development of customized microstructures in gas separation membranes via defect engineering remains nascent. Hence, this review is designed to serve as a comprehensive guide for the application of defect engineering in 2D nanomaterial-based membranes. It delves into the most recent developments in this field, encompassing the synthesis methodologies of defective 2D nanomaterials and the mechanisms underlying gas transport. Special emphasis is placed on the utilization of defect-engineered 2D nanomaterial-based membranes in gas capture applications. Furthermore, the paper encapsulates the burgeoning challenges and prospective advancements in this area. In essence, defect engineering emerges as a promising avenue for enhancing the efficacy of 2D nanomaterial-based membranes in gas separation, offering significant potential for advancements in membrane-based gas separation technologies. [ABSTRACT FROM AUTHOR]

In this work, we used a previously described computational fluid dynamics (CFD) model of a roll‐to‐roll coating process for the fabrication of thin‐film composite membranes to predict the final coating thickness for PolyActive™, a commercially available multiblock copolymer utilized for CO2 removal membranes. We found a strong thickening effect that could not be explained by our previous model. We investigated the process experimentally. In addition, we conducted a variety of simulations with extensions of the initial CFD model. Based on our findings, we conclude that the Marangoni effect, that is, gradients of surface tension that induce secondary flow patterns in the meniscus region, is the most likely source of the observed thickening. We explain the simulation results in order to understand the physical mechanisms at play and to show how especially surface tension gradients that arise from the particular flow structure in the meniscus may explain the additional transfer of polymer solution to the membrane. Finally, we draw some conclusions on future research and give ideas on future improvements of the process. To our knowledge, Marangoni effects for the coating of PolyActive™ were not described so far in the literature, even though it is a well‐known polymer for gas separation membranes targeted at CO2 removal. Roll‐to‐roll coating is a well‐established coating method and often believed to be suitable for the scale‐up of membrane production, therefore we think that this work will help membrane researchers who are using similar coating devices to be cautious about possible complications in the process. [ABSTRACT FROM AUTHOR]

The problem of parametric identification of some nonlinear models of fast hydrogen permeability of alloys for membrane technologies for the release of high-purity hydrogen (on the example of alloy B1) is solved. Not only diffusion in the bulk of the material is taken into account, but also physical and chemical processes on the surface: adsorption, desorption and rapid dissolution. The mathematical software and the results of numerical simulation for a three-stage breakthrough experiment with vacuum pumping at the membrane outlet from the structural material under study are presented. The influence of the accumulation of atomic hydrogen on the surface has been studied. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental and model studies of the pressure swing adsorption (PSA) process in a column with a zeolite 13X bed with a height of 0.5 m. The gas mixture consisted of CO2 (10–20%), N2, and H2O (RH 50%) in different ratios. As a result of the column tests, concentration, and temperature evolutions were obtained for each of the adsorption and desorption stages, which were used to determine the breakthrough and bed saturation times and other parameters important for the analysis of the column operation. A mathematical model of the PSA process for the separation of CO2 from the gas mixture was developed. The system of second-order partial differential equations was solved using Matlab software. The research focuses on adsorptive CO2 capture and shows the influence of water vapor and operational parameters on the quality of model validation. [ABSTRACT FROM AUTHOR]

Aligned with the recent trend and imperative to reduce separation layer thickness in gas separation membranes to the nanometer scale in order to raise permeance to levels that can render them competitive with respect to other gas separation technologies, a novel approach and device for fabricating defect-free composite hollow fiber (HF) membranes by dip-coating is described. The presented method avoids the fundamental drawbacks of state-of-the-art techniques for applying a thin gas separation layer onto a porous HF substrate, providing a safe but, at the same time, easily up-scalable way of producing HF membranes at a relatively high production rate. As a basic concept, hanging HF substrates are coated by allowing the coating solution to flow and drip along their external surface. The adaptability of this method, stemming from the array of available coating solutions (a plethora of dispersed nanofillers) and the multitude of substrate options, holds great promise for the fabrication of highly selective and defect-free composite HF membranes. [ABSTRACT FROM AUTHOR]

Waste heat recovery holds significant importance in the context of natural gas power plants, as it facilitates the utilization of energy loss, leading to enhanced overall performance and mitigating adverse environmental effects. By harnessing and employing waste heat, power plants possess the capability to modify and optimize their operation, making a substantial contribution toward sustainable power/energy generation. Therefore, this study proposes a novel and eco-friendly approach to utilizing the flue gas emitted by a natural gas power plant. In addition to recovering waste heat, this method involves harnessing the flue gas for methanol production. The proposed system consists of an organic Rankine cycle, and absorption chiller, heating provider units, an electrolyzer for hydrogen generation, and a methanol synthesis unit. The novel method is implemented through computer-aided simulation using the Aspen HYSYS software and is subjected to an extensive analysis encompassing energy, exergy, environmental, and economic viewpoints. The simulation results exhibit producing 2712 kg/h of methanol with a purity of 99.97 mol%, 395.67 kg/s of hot water, 378 kg/s of chilled water, and 12253.57 kW of power. In this process, the energy and exergy efficiencies are 94.35% and 31.74%, respectively. Parametric study results demonstrate that reducing the gas turbine pressure and increasing the working fluid temperature in the evaporator of the absorption chiller cycle leads to improved exergy efficiency. Moreover, the multigeneration scenario shows a carbon dioxide footprint of 0.1564 kg/kWh and a total unit cost of product of 0.0485 $/GJ. • Modification of a natural gas power plant by heat recovery and flue gas utilization. • Innovative CCHP-methanol generation application combined with a natural gas power plant. • Aspen HYSYS software is used to simulate the model and conduct a multi-variable study. • The whole system shows energy and exergy efficiencies of 94.35% and 31.74%. • Multigeneration scenario shows CO 2 footprint of 0.1564 kg/kWh and TUCP of 0.0485 $/GJ. [ABSTRACT FROM AUTHOR]

Pressure swing adsorption(PSA) based gas separation technology is widely applied in chemical industries, especially in hydrogen purification. Its complex mechanism and non-steady state feature restrict the separation performance adjustment and application on efficient gas utilization. Process simulation, machine learning and modelling combined innovating gas management methodology is proposed in this paper to perform accurate gas separation for natural gas based syngas mixture. VB script program is employed to drive Aspen adsorption simulation, and then classical and regression tree(CART), polynomial regression(PNR) and surrogate model are comprehensively used to perform machine learning. Consequently, the coefficient matrix is obtained to quantify the separation performance. This method holds the potential for broader application in refineries and SPCs hybrid hydrogen network, facilitating the comprehensive utilization of hydrogen containing gases. Case study results show this methodology can conserve natural gas and gas productivity by 21.3 %, as well as carbon emission by 8211.6 Nm3/h. This work highlights the promising application of digital twin technology within the chemical industry, showcasing how process simulation, machine learning, and modeling can collectively revolutionize gas management and resource conservation. [Display omitted] • Novel PSA based gas allocation instead of gas separation technology. • Simulation, modelling and machine learning combined gas accommodating methodology. • An insight technology for integration of refinery and SPC. • A novel gas allocation method for zero waste of hydrogen. • An insight application of digital twin technology for gas efficient utilization. [ABSTRACT FROM AUTHOR]

Polyimides are a polymer class that has been extensively investigated as a membrane material for gas separation owing to its interesting permselective properties in a wide range of operation temperatures and pressures. In order to improve their properties, the addition of different filler types is currently studied. p-tert-Butylcalix[n]arene macrocycles (PTBCs) with different cavity sizes (PTBC4, PTBC6, PTBC8) were used as fillers in a commercial thermoplastic polyimide, with a concentration in the range 1–9 wt%, to develop nanocomposite membranes for gas separation. The selected macrocycles are attractive organic compounds owing to their porous structure and affinity with organic polymers. The nanocomposite membranes were prepared in the form of films in which the polymeric matrix is a continuous phase incorporating the dispersed additives. The preparation was carried out according to a pre-mixing approach in a mutual solvent, and the solution casting was followed by a controlled solvent evaporation. The films were characterized by investigating their miscibility, morphology, thermal and spectral properties. The gas transport through these films was examined as a function of the temperature and also time. The results evidenced that the incorporation of the chosen nanoporous fillers can be exploited to enhance molecular transport, offering additional pathways and promoting rearrangements of the polymeric chains. [ABSTRACT FROM AUTHOR]

Imidazole ionic liquids (ILs) have good affinity and good solubility for carbon dioxide (CO2). Such ionic liquids, combined with polyimide membrane materials, can solve the problem that, today, CO2 is difficult to separate and recover. In this study, the ionic liquid (IL) of 1-ethyl-3-methylimidazolium tetrafluoroborate (IL1), 1-pentyl-3-methylimidazolium tetrafluoroborate (IL2), 1-octyl-3-methylimidazolium tetrafluoroborate (IL3), and 1-dodecylimidazolium tetrafluoroborate (IL4) with different contents were added to a polyimide matrix, and a series of polyimide membranes blended with ionic liquid were prepared using a high-speed mixer. The mechanical properties and gas separation permeability of the membranes were investigated. Among them, the selectivity of the PI/IL3 membrane for CO2/CH4 was 180.55, which was 2.5 times higher than the PI membrane, and its CO2 permeability was 16.25 Barrer, which exceeded the Robeson curve in 2008; the separation performance of the membrane was the best in this work. [ABSTRACT FROM AUTHOR]

Chemical modification of cellulose is challenging due to its low reactivity and poor solubility. Halogenation followed by displacement reactions has been demonstrated to be a valuable strategy for appending new functionalities to the anhydroglucose rings of cellulose and cellulose derivatives. In this paper, we report a simple and efficient pathway to modify the inexpensive, commercial cellulose ether, hydroxyethyl cellulose (HEC). First, methanesulfonyl chloride (MsCl) in N, N-dimethyl formamide (DMF) can selectively chlorinate the terminal primary hydroxyl groups from hydroxyethyl cellulose (HEC), thereby affording high terminal chloride content. Then, the resulting chlorinated HEC undergoes displacement reactions with various nucleophiles including azide (NaN3), amine (1-methylimidazole), and thiols (3-mercaptopropionic acid and 2-mercaptoethanol). All products were characterized by NMR and FT-IR spectroscopic methods. Exploiting this strategy, we prepared a library of HEC derivatives, including cationic and anionic derivatives, which are of great interest in various applications including as surfactants, in gas separation membranes, and as crystallization inhibitors in amorphous solid dispersions for oral drug bioavailability enhancement. [ABSTRACT FROM AUTHOR]