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Adhesion between fillers and a polymeric matrix is an essential characteristic for mixed-matrix membranes for molecular separation to avoid defects and cavities that would decrease selectivity. We ...

Food packaging with efficient antibacterial ability is highly desirable and challenging in facing the crisis of microbial contamination. However, most present packaging is based on metal-based antibacterial agents and requires a time-consuming antibacterial process. Here, the unique packaging (CC/BB films) featuring aggregation-induced emission behavior and photodynamic inactivation activity is prepared by dispersing self-assembled berberine-baicalin nanoparticles (BB NPs) into a mixed matrix of sodium carboxymethylcellulose-carrageenan (CC). The superiority of this design is that this packaging film can utilize sunlight to generate reactive oxygen species, thus eradicating more than 99% of E. coli and S. aureus within 60 min. Also, this film can release BB NPs to inactivate bacteria under all weather conditions. Surprisingly, the CC/BB nanocomposite film presented excellent mechanical performances (29.80 MPa and 38.65%), hydrophobicity (117.8°), and thermostability. The nanocomposite film is validated to be biocompatible and effective in protecting chicken samples, so this work will provide novel insights to explore safe and efficient antibacterial food packaging.

Ionic liquids (ILs) have become attractive in membranes for CO₂ separation because of the designable structure, high CO₂ affinity, and good compatibility and stability. Modification of metal–organic frameworks with ILs is an effective strategy to improve the gas separation performance of mixed matrix membranes (MMMs). In this work, task-specific ionic liquids (TSILs) were incorporated to prepare TSIL@ZIF-67/PIM-1 MMMs and improve CO₂ separation performance because of the high CO₂ solubility and great compatibility toward ZIF-67 and PIM-1. The TSILs (TMGHIM and TMGHPhO) selectively and reversibly interact with CO₂ and improve the interfacial compatibility between ZIF-67 and PIM-1, leading to higher CO₂/CH₄ and CO₂/N₂ selectivities than that of the ZIF-67/PIM-1 MMM and the directly blended membrane (TSIL/ZIF-67/PIM-1). The 10 wt % TMGHIM@ZIF-67/PIM-1 MMM shows enhanced CO₂/N₂ and CO₂/CH₄ selectivities of 13.7 and 10.5, respectively; meanwhile, the CO₂ permeability reaches 12,848.5 Barrer and is 2.5 times that of the pure PIM-1 membrane. The TSIL@ZIF-67/PIM-1 MMMs also show good stability against physical aging.

Metal–organic framework (MOF)-based mixed matrix membranes have become a research hotspot in separation field owing to the compatibility between MOF particles and the polymeric matrix. Herein, thre...

A facile strategy to elevate gas separation performances of polymers is to introduce a versatile particle. In this study, the novel F-Ce nanosheets are synthesized, and then F-Ce is functionalized ...

Separation technology by using membranes is an effective choice for water treatment, but fouling is a significant problem for membrane applications. Recently, transition-metal dichalcogenide nanosh...

Mixed-matrix membranes (MMMs) have received considerable interest because of their capability to synergize polymeric and nanomaterials. Extensive experimental and a handful of simulation studies on...

Covalent organic frameworks (COFs) are increasingly utilized as doping agents for the design of advanced ultrafiltration mixed matrix membranes, thanks to their prominent nanoporosity and excellent...

The interfacial design is critical in preparing high-performance mixed matrix membranes (MMMs), especially for the separation of larger sized components from mixtures. Herein, a facile and novel st...

Fine-tuning and pore environment control of covalently connected metal-organic framework (MOF) and mixed-matrix membrane (MMM) composite materials were achieved. Core-shell-type, dual-functionalize...

Membrane technology without a phase-change process has demonstrated its low-cost, high-energy-efficiency advantages. High fractional free volume polymers of intrinsic microporosity (PIMs), such as ...

Most examples of mixed-matrix membranes (MMMs) involve one type of polymer and one type of inorganic filler particle. Here, both polymer blending and MMM approaches are combined to form exceptional...

Despite the large number of reports on the utilization of highly microporous solids, most relevant are metal-organic frameworks (MOFs), in different demanding applications, the successful hybridization of MOFs and moldable polymer matrices into flexible, water-permeable membranes exhibiting strong entanglement of the MOF and the polymer matrix properties is still lacking. We describe herein an efficient pathway to construct a mixed-matrix membrane (MMM) comprising a water-stable metal-organic framework (UiO-66-NH

This study first develops a facile method to synthesize zeolitic imidazolate framework cuboid (ZIF-C) nanosheets with tunable thickness from 70 to 170 nm from aqueous polymer solutions. The obtaine...

This paper describes a new architecture of mixed matrix membranes (MMMs), taking full benefit of the functionalities of a metal–organic framework (MOF). NH2-functionalized zirconium carboxylate MOF...

Mixed-matrix membranes (MMMs) composed of a metal-organic framework (MOF, UiO-66) and a (poly(ethylene-co-vinyl acetate) (EVA) copolymer were synthesized with a range of MOF loadings. The MOF pores...

Membrane-based separations can mitigate the capital- and energy-intensive challenges associated with traditional thermally driven processes. To further push the boundary of gas separations, mixed matrix membranes (MMMs) have been extensively exploited; however, identifying an optimal nanofiller to boost the separation performance of MMMs beyond Robeson permeability-selectivity upper bounds remains an ongoing challenge. Here, a new class of MMMs based on pyrazine-fused crystalline porous graphitic frameworks (PGFs) is reported. At a loading of 6 wt % PGFs, the MMMs surpass the current H2/CH4 Robeson upper bound, ideally suited for applications such as H2 regeneration. In addition, the fabricated MMMs exhibit appealing CO2 separation performance, closely approaching the current Robeson upper bounds for CO2 separation. Compared with the pristine polymeric membranes, the PGF-based MMMs display a record-high enhancement of gas permeability over 120% while maintaining intrinsic gas selectivities. Highlighting the crucial role of the crystallinity of nanofillers, this study demonstrates a facile and effective approach in formulating high-performance MMMs, complementing state-of-the-art membrane formation processes. The design principles open the door to energy-efficient separations of gas mixtures with enhanced productivity compatible with the current membrane manufacturing.

We engineer the interfacial characteristics of a ZIF-8–6FDA–durene polyimide (PI) polymer mixed matrix membrane in silico by using an ionic liquid (IL) at the polymer–ZIF interface for improved CO2...

Postprint Bearing in mind that Metal Organic Frameworks (MOFs) have remarkable CO2 adsorption selectivity and Mixed Matrix Membranes (MMMs) have been identified as potential solution for advancing the current state of the art of membrane separation technology, this work investigates the effect of combining a MOF, with high adsorption properties towards CO2 when compared to CH4 (MOF-5), with a blend of poly(ionic liquid)/ionic liquid (PIL/IL) for biogas upgrading. The blend system consisted of a pyrrolidinium-based PIL, poly([Pyr11][Tf2N]), and a free imidazolium-based IL, [C2mim][BETI]. The MOF-5 was incorporated at different loadings (10, 20, 30 wt%), and MMMs were prepared by solvent evaporation technique and characterized by diverse techniques (FTIR, SEM, TGA, puncture tests, water contact angle and single gas transport). The results showed that the free IL is miscible with the PIL, while MOF-5 particles were uniformly dispersed into the PIL/IL matrix. The formed PIL/IL/MOF-5 membranes revealed suitable thermal stability (Tonset up to 656 K) for biogas upgrading processes, but a loss of mechanical stability was found after the incorporation of MOF-5, and thus more rigid and fragile membranes were obtained. Besides, increasing MOF-5 content in the MMMs resulted in improved CO2 permeability. At 30 wt% of MOF-5 loading the CO2 permeability increased 133% when compared to that of the pristine PIL/IL membrane, while the ideal selectivity CO2/CH4 decreases. It was possible to demonstrate the relevance of studying different components within the polymeric matrix in order to assess not only thermal, mechanical and chemical properties, but also gas transport response. This work was supported by FCT (Fundação para Ciência e a Tecnologia) through the project PTDC/CTM-POL/2676/2014 and the Associate Laboratory for Green Chemistry - LAQV (UID/QUI/50006/2019). Ana R. Nabais and Luísa A. Neves are grateful to FCT/MCTES for their PhD grant (SFRH/BD/136963/2018) and FCT Investigador Contract (IF/00505/2014), respectively. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 745734.

Blending porous inorganic fillers into polymers to fabricate mixed matrix membranes (MMMs) is an efficient method to acquire good-quality membranes for CO2 separation and purification. The poor int...

Polymers of intrinsic microporosity (PIMs) exhibit high permeability but moderate selectivity, which limits their industrial application in membrane gas separations. Here, a novel CO2-philic perflu...

Highlighting mixed matrix membrane (MMM) susceptibility in improving the membrane performance along with established p-tert-butylcalix[4]arene (CA) ability in CO2 sorption, Pebax-1657-based MMMs ha...

This work systematically investigates an exemplary mixed-matrix membrane (MMM) system composed of a UiO-66-NH2 metal–organic framework (MOF) and a 6FDA-Durene polyimide. The UiO-66-NH2 MOF is post-...

Polyhedral oligomeric silsesquioxane (POSS) is a promising nanofiller with a cubic inorganic framework and optional organic functional groups. In this work, organosilica–POSS mixed matrix membranes...

Polymer gas separation membranes, especially the mixed matrix membranes (MMMs) that consist of polymer matrix and additives, find important applications in carbon dioxide (CO2) separation or captur...

As an important type of reactive oxygen species (ROS), hypochloric acid (HClO) is closely linked with our daily life, and its convenient and rapid detection is very significant and imperative. Fluorescent and visual probes are being recognized as powerful and convenient tools for detection of ROS in the environment and living organisms by visualizing and imaging. In this contribution, a new metal-organic framework-based fluorescent probe

Although high flux membranes are indispensable to membrane-based gas separation technologies, enhancing membrane permeability proves to be difficult due to the trade-off between permeability and ga...

A novel polysulfone–cerium oxide (Psf–ceria) mixed-matrix membrane (MMM) with enhanced γ radiation resistant property was developed. Ceria nanoparticles were synthesized by gel-combustion route and...

Mixed matrix membranes (MMMs), which are fabricated by incorporating dispersed fillers into a continuous polymeric matrix, have been broadly utilized in gas separation due to their unique hierarchical structures and enhanced separation performance. Fillers of intrinsic nanopores (FINs) have drawn considerable attention because they not only can provide additional molecular transport channels but also have a potential size-sieving property. Although many excellent reviews about MMMs have been published, quite few of them are specifically designed for MMMs containing FINs. This Review focuses on three kinds of FINs, covalent organic frameworks (COFs), zeolites, and metal–organic frameworks (MOFs), as the representatives of organic, inorganic, and inorganic–organic FINs. The typical physical and chemical features of these three kinds of FINs are introduced. Afterward, methods to prepare FIN-based MMMs are briefly introduced. Particularly, solutions to prevent the aggregation and improve the dispersion of FIN...

A three-component (cross-linked poly(ionic liquid) (PIL)–ionic liquid (IL)–zeolite), mixed-matrix membrane (MMM) platform based on curable IL prepolymers of controlled length has been developed for...

Efficient separation of CO2 from CO2/CH4 mixtures using membranes has economic, environmental and industrial importance. Membrane technologies are currently dominated by polymers due to their processing abilities and low manufacturing costs. However, polymeric membranes suffer from either low gas permeabilities or low selectivities. Metal organic frameworks (MOFs) are suggested as potential membrane candidates that offer both high selectivity and permeability for CO2/CH4 separation. Experimental testing of every single synthesized MOF material as membranes is not practical due to the availability of thousands of different MOF materials. A multilevel, high-throughput computational screening methodology was used to examine the MOF database for membrane-based CO2/CH4 separation. MOF membranes offering the best combination of CO2 permeability (>10(6) Barrer) and CO2/CH4 selectivity (>80) were identified by combining grand canonical Monte Carlo and molecular dynamics simulations. Results revealed that the best MOF membranes are located above the Robeson's upper bound indicating that they outperform polymeric membranes for CO2/CH4 separation. The impact of framework flexibility on the membrane properties of the selected top MOFs was studied by comparing the results of rigid and flexible molecular simulations. Relations between structures and performances of MOFs were also investigated to provide atomic-level insights into the design of novel MOFs which will be useful for CO2/CH4 separation processes. We also predicted permeabilities and selectivities of the mixed matrix membranes (MMM) in which the best MOF candidates are incorporated as filler particles into polymers and found that MOF-based MMMs have significantly higher CO2 permeabilities and moderately higher selectivities than pure polymers., European Union (EU); H2020; European Research Council (ERC)-2017-Starting Grant; COSMOS

Membrane gas separation is a mature and expanding technology. However, the availability of better membrane materials would promote faster growth. In this Perspective we analyze the state of the art of membrane materials, including polymers and hybrid materials, as well as the current issues and barriers, and finally, we outline future research directions in membrane science. Development of new membrane materials for large scale separations will rely on a multidisciplinary approach that embraces the broad fields of chemical and materials engineering, polymer science, and materials chemistry.

Obtaining strong interfacial affinity between filler and polymer is critical to the preparation of mixed matrix membranes (MMMs) with high separation efficiency. However, it is still a challenge for micron-sized metal organic frameworks (MOFs) to achieve excellent compatibility and defect-free interface with polymer matrix. Thin layer of ionic liquid (IL) was immobilized on micron-sized HKUST-1 to eliminate the interfacial nonselective voids in MMMs with minimized free ionic liquid (IL) in polymer matrix, and then the obtained IL decorated HKUST-1 was incorporated into 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-2,3,5,6-tetramethyl-1,3-phenyldiamine (6FDA-Durene) to fabricate MMMs. Acting as a filler/polymer interfacial binder, the favorable MOF/IL and IL/polymer interaction can facilitate the enhancement of MOF/polymer affinity. Compared to MMM with only HKUST-1 incorporation, MMM with IL decorated HKUST-1 succeeded in restricting the formation of nonselective interfacial voids, leading to an increment in CO

In this study, a carbon nanotubes composite coated with N-isopropylacrylamide hydrogel (NIPAM-CNTs) was synthesized. Mixed-matrix membranes (MMMs) were fabricated by incorporating NIPAM-CNTs composite filler into poly(ether-block-amide) (Pebax MH 1657) matrix for efficient CO2 separation. The as-prepared NIPAM-CNTs composite filler mainly plays two roles: (i) The extraordinary smooth one-dimensional nanochannels of CNTs act as the highways to accelerate CO2 transport through membranes, increasing CO2 permeability; (ii) The NIPAM hydrogel layer coated on the outer walls of CNTs acts as the super water absorbent to increase water content of membranes, appealing both CO2 permeability and CO2/gas selectivity. MMM containing 5 wt % NIPAM-CNTs exhibited the highest CO2 permeability of 567 barrer, CO2/CH4 selectivity of 35, and CO2/N2 selectivity of 70, transcending 2008 Robeson upper bound line. The improved CO2 separation performance of MMMs is mainly attributed to the construction of the efficient CO2 transpo...

A series of 6FDA-Durene-ZIF71 mixed matrix membranes (MMMs) comprising three different ZIF-71 particle sizes (i.e., 30, 200, and 600 nm) have been fabricated to investigate the effects of particle size on the gas separation performance of MMMs. Compared to MMMs containing ZIF-71 particle size > 200 nm, ZIF-71 embedded MMMs with particle sizes of ≤ 200 nm exhibited significantly enhanced gas separation performance. The O2 and N2 permeability of MMMs comprising ZIF-71 with particle sizes ≤ 200 nm have higher permeability than the predicted ones using the Maxwell model. By considering the inefficiently packed polymer chain and the sieve-in-a-cage phenomena, the modified Maxwell model displayed comparable permeability over the experimental results suggesting the nonideal nature of MMMs. For the first time, it was found that 200 nm ZIF-71 generated the best MMM for gas separation, particularly for H2/CH4 systems. Therefore, a trade-off between ZIF-71 particle size vs gas separation performance must be taken in...

Carbon nanotube (CNT) mixed-matrix membranes (MMMs) show great potential to achieve superior gas permeance because of the unique structure of CNTs. However, the challenges of CNT dispersion in polymer matrix and elimination of interfacial defects are still hindering MMMs to be prepared for high gas selectivity. A novel CNT/metal-organic framework (MOF) composite derived from the growth of NH2-MIL-101(Al) on the surface of CNTs have been synthesized and applied to fabricate polyimide-based MMMs. Extra amino groups and active sites were introduced to external surface of CNTs after MOF decoration. The good adhesion between the synthesized CNT-MIL fillers and polymer phase was observed, even at a high filler loadings up to 15%. Consequently, MMMs containing the synthesized MOF/CNT composite exhibit not only a large CO2 permeability but also a high CO2/CH4 selectivity; the combined performance of permeability and selectivity is even above the Robeson upper bound. The strategy of growing MOFs on CNTs can be further utilized to develop a more effective approach to further improve MMM performance through the decoration of MOFs on existing fillers that have high selectivity to specific gas.

Porous additives offer an attractive pathway to enhance the performance of polymeric gas separation membranes. Previously reported porous additives, such as zeolites and metal–organic frameworks, suffer from poor interfacial binding with the polymer matrix, which leads to nonselective gas transport pathways. Porous organic cages (POCs) are an exciting new family of soluble additives that could ameliorate these transport issues by integrating intimately with the polymer matrix. By using Voronoi network analysis, grand canonical Monte Carlo simulations, and molecular dynamics, we provide a theoretical assessment of the benefit of using POCs as additives for mixed matrix membranes (MMMs). We reveal that some MMMs containing POCs exhibit enhanced selectivity and permeability compared to the neat polymer matrix, particularly for H2/CO2 separations.

The demand for cost-efficient separations requires membranes with high gas flux and high selectivity which opens the path for further improvements. Mixed matrix membranes (MMMs) made from 33.3 wt % ZIF-8 in 6FDA-durene were tested at 35 °C and 3.5 atm. At 33.3 wt % loading of ZIF-8, H2, N2, O2, and CH4 gas permeabilities increased approximately 400%. Cross-linking the surface of this MMM, by reacting with ethylenediamine vapor, yielded a 10-fold increase in H2/CO2, H2/N2, and H2/CH4 selectivities with respect to 6FDA-durene, preserving 55% of the H2 permeability of 6FDA-durene. The permselective properties of the cross-linked skin of the MMM fall above the most recent permeability–selectivity trade-off lines (2008 Robeson upper bounds) for H2/CO2, H2/N2, and H2/CH4 separations. To the best of our knowledge, this is the first example of a cross-linked ZIF/polymer MMM for gas separation.

We used molecular simulations to assess the performance of zeolite imidazolate framework (ZIF) based mixed matrix membranes (MMMs) for CO2/CH4, H2/CH4, and H2/CO2 separations. The gas permeability of ZIF based MMMs was estimated based on the gas permeability of pure ZIFs obtained from molecular simulations and the gas permeability of pure polymers obtained from experimental studies. Predicted gas selectivity and permeability were compared with the available experimental data of MMMs in which ZIF-8 and ZIF-90 were used as filler particles. After showing the good agreement between the predictions of theoretical methods and experiments, we estimated gas selectivity and permeability of 360 new MMMs composed of 15 different ZIFs and 24 different polymers. Our results showed that ZIF-11 based MMMs exhibit high performance for separation of CO2/CH4 whereas ZIF-65 based MMMs are good candidates for H2/CO2 separation.

In this study, the challenge of selecting metal–organic frameworks (MOFs) as filler particles in high-performance mixed-matrix membranes (MMMs) was examined using atomistic and continuum modeling. We tested several theoretical permeation models, including the Maxwell, modified Maxwell, Bruggeman, Lewis–Nielson, Pal, Felske, and modified Felske models, by comparing the predictions of these models with the experimental data for IRMOF-1/Matrimid and CuBTC/Matrimid MMMs. After identifying the model making the best predictions, we examined the performance of 80 new MOF-based MMMs composed of 10 different MOFs and eight different polymers for CO2/CH4 separations. Our results show that selecting the appropriate MOF as filler particles in polymers can result in MMMs with extraordinarily high CO2 selectivities and CO2 permeabilities relative to those of pure polymer membranes. The methods introduced in this study will create many opportunities for selecting MOF/polymer combinations for MMMs with useful properties for CO2 separation applications., European Commission; Marie Curie International Reintegration

A mesoporous MCM-48 silica was synthesized by a templating method and mixed with polysulfone (PSF) to fabricate mixed matrix membranes (MMMs). Helium permeation data and SEM images of as-synthesize...