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 obtained ...ZIF-C nanosheets were characterized by various techniques, including X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N2 adsorption and thermogravimetric analysis (TGA), to understand their compositional and structural properties. The synthesized ZIF-Cs nanosheets with different thicknesses were further applied as nanofillers to prepare Pebax-based mixed matrix membranes (MMMs) to study the effect of the morphology on membrane properties and CO2/N2 separation performances under different relative humidity (RH) conditions. Results reveal that the incorporation of these ZIF-Cs simultaneously enhances CO2 permeability and CO2/N2 selectivity in the mixed matrix membranes. In addition, MMMs with the thickest ZIF-C nanosheet present better performance. A CO2 permeability of 387.2 Barrer accompanied with a CO2/N2 selectivity of 47.1 has been documented, nearly doubled in CO2 permeability with slightly increased selectivity compared with membranes containing thinner nanosheets.
In this work, defect-free thin-film-composite (TFC) hollow fiber membranes containing various amino acid salts as CO2 facilitated transport carriers were fabricated via dip-coating. Four different ...amino acid salts, i.e., potassium prolinate (ProK), potassium argininate (ArgK), potassium glycinate (GlyK) and potassium cysteinate (CysK), were selected and embedded within polyvinyl alcohol (PVA) matrix. TGA, FTIR, SEM and humid mixed gas permeation test were used for the evaluation. Experiments show that adding amino acid salts into the PVA matrix significantly increases the CO2 permeance with little influence on the CO2/N2 selectivity. ProK was found the most effective within the four investigated mobile carriers; The addition of 40% ProK into the PVA matrix nearly doubled the CO2 permeance (from 399 to 791 GPU). The PVA/amino acid salt membranes also exhibited good long-term stability, in which both CO2 permeance and CO2/N2 selectivity remained nearly unchanged in a 20-h test and after a two-week shutdown period.
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•Four amino acid salts were used as mobile carriers in PVA-based membranes to enhance CO2 transport.•Defect-free TFC hollow fiber membranes with selective layer thicknesses of <500 nm were fabricated.•Lab-size hollow fiber membrane module was prepared and tested using humid mixed feed gas.•Adding amino acid salt improves the CO2 permeance significantly without sacrificing the selectivity.•The membranes show good long-term stability in the test and after a shutdown operation.
The development of multilayer composite membranes for CO2 separation has gained increasing attention due to the desire for energy efficient technologies. Multilayer composite membranes have many ...advantages, including the possibility to optimize membrane materials independently by layers according to their different functions and to reduce the overall transport resistance by using ultrathin selective layers, and less limitations on the material mechanical properties and processability. A comprehensive review is required to capture details of the progresses that have already been achieved in developing multilayer composite membranes with improved CO2 separation performance in the past 15–20 years. In this review, various composite membrane preparation methods were compared, advances in composite membranes for CO2/CH4 separation, CO2/N2 and CO2/H2 separation were summarized with detailed data, and challenges facing for the CO2 separation using composite membranes, such as aging, plasticization and long-term stability, were discussed. Finally the perspectives and future research directions for composite membranes were presented.
•A pre-pilot scale amino acid salts based facilitated transport HF membrane was fabricated.•The membrane module was tested for CO2 capture from the real stream flue gas with impurities.•Gas ...separation test was carried out in the temperature range of 80–115 °C.•The effects of process operation parameters on the membrane separation performances were investigated.•The membrane stability in the real separation conditions was studied from a one-week test.
In this work, a pre-pilot scale hollow fiber membrane module with a PVA/ProK hybrid membrane containing up to 40 wt% amino acid salt was fabricated and tested infield for CO2 capture. The petroleum coke-fired flue gas generated from the rotary kiln provided with a 5-stage cyclone pre-heater tower for the production of grey clinker in the Colacem cement plant in Gubbio (PG), Italy, was used as feed gas after a simple filtration to remove the suspended particulate matter without further pretreatment. The temperature for the membrane test was ranging from 80 to 115 °C. The effects of various parameters including operation temperature, pressure, sweep gas flow rate, vacuum grade, and the impurities in the feed were systematically investigated. Under optimized condition, CO2 content of 50% in the permeate and CO2 permeate flux of ˜5 × 10−3 cm3(STP) cm−2 s−1 were documented, which is comparable with other facilitated transport membranes. The presence of impurities in the feed stream showed a negligible effect on the CO2 separation performance. Long-term stability was also studied through a test for a duration of 1 week at 90 °C.
CO2 separation performance in facilitated transport membranes has been reported depended not only on the CO2 carrier properties but also to a great extent on the polymeric matrix regarding the ...capacity of retaining water and carriers as well as the processability for coating defect-free ultra-thin films. In this study, the blends of hydrophilic polymers polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) were studied to find an optimal polymer matrix to host carriers in facilitated transport membranes for enhanced CO2 separation. It is found out that the optimized blend is 50/50 PVA/PVP by weight, which shows a significant increase in the water uptake (from 63 to 84%) at equilibrium state compared to the neat PVA. Polyethyleneimine (PEI) was employed to provide sample carriers to evaluate the synergistic effect of PVA and PVP on the CO2 separation performance. A thin film composite (TFC) membrane of the optimized blend (50/50 PVA/PVP with 50 wt% PEI) was fabricated on polysulfone (PSf) porous support. The fabrication of the TFC membranes is simple and low cost, and CO2 permeance of the optimized blend membrane is nearly doubled with the CO2/N2 selectivity remained unchanged, showing great potential for industrial applications of the resulted membranes.
A polymeric matrix suitable to host CO2 facilitated transport carriers was optimized by blending PVA and PVP. The water-retention of the blend membrane and the processability for thin-film coating were improved, showing synergetic enhancement on CO2 separation permeance. Display omitted
Application of conventional polymeric membranes in CO₂ separation processes are limited by the existing trade-off between permeability and selectivity represented by the renowned upper bound. ...Addition of porous nanofillers in polymeric membranes is a promising approach to transcend the upper bound, owing to their superior separation capabilities. Porous nanofillers entice increased attention over nonporous counterparts due to their inherent CO₂ uptake capacities and secondary transport pathways when added to polymer matrices. Infinite possibilities of tuning the porous architecture of these nanofillers also facilitate simultaneous enhancement of permeability, selectivity and stability features of the membrane conveniently heading in the direction towards industrial realization. This review focuses on presenting a complete synopsis of inherent capacities of several porous nanofillers, like metal organic frameworks (MOFs), Zeolites, and porous organic frameworks (POFs) and the effects on their addition to polymeric membranes. Gas permeation performances of select hybrids with these three-dimensional (3D) fillers and porous nanosheets have been summarized and discussed with respect to each type. Consequently, the benefits and shortcomings of each class of materials have been outlined and future research directions concerning the hybrids with 3D fillers have been suggested.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
To mitigate the effect of atmospheric CO
2
on global climate change, gas separation materials that simultaneously exhibit high CO
2
permeability and selectivity in gas mixtures must be ...developed. In this study, CO
2
transport through midblock-sulfonated block polymer membranes prepared from four different solvents is investigated. The results presented here establish that membrane morphology and accompanying gas transport properties are sensitive to casting solvent and relative humidity. We likewise report an intriguing observation: submersion of these thermoplastic elastomeric membranes in liquid water, followed by drying prior to analysis, promotes not only a substantial change in membrane morphology, but also a significant improvement in both CO
2
permeability and CO
2
/N
2
selectivity. Measured CO
2
permeability and CO
2
/N
2
selectivity values of 482 Barrer and 57, respectively, surpass the Robeson upper bound, indicating that these nanostructured membranes constitute promising candidates for gas separation technologies aimed at CO
2
capture.
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•Progress in membranes for CO2 capture and separation has been thoroughly reviewed.•Membrane materials for CO2 separation has been summarized.•Industrial application of CO2 separation ...membranes has been discussed.•Future development of CO2 separation membranes materials and membrane processes have been proposed.
Industry interest in CO2 capture and separation has grown almost exponentially over the past decades. This paper aims to promote membrane technology as a viable solution for this application and provide a reference for the industry seeking efficient CO2 separation solutions. First, a brief summary of the basics of mass transport mechanisms, various membrane materials, and module configurations is presented as the basis for the discussion. Special focus has been paid on different membrane materials developed in the past few years. Then, the latest advances in CO2 separation membranes and processes in the context of industrial applications are outlined, including pilot tests carried out all over the world, as well as commercially available CO2 separation membrane materials and modules. Afterwards, the application of big data and machine learning on CO2 separation membranes have also been reviewed. Finally, challenges and gaps that hinder the implementation of membrane technology and future directions for membrane development from laboratory to industry are discussed.
Urgent actions are needed to reduce CO2 emissions and mitigate the increasingly severe impacts of climate change. Since the 1990s, the membrane research group (MEMFO) at the Norwegian University of ...Science and Technology has been committed to developing effective membranes and membrane processes for CO2 separation. MEMFO's research can be categorized into five main themes: facilitated transport membranes, hybrid membranes, carbon membranes, membrane contactors, and related modeling and process simulation. These themes are tied to industrial applications in CO2 capture from flue gas, biogas upgrading, natural gas sweetening, and hydrogen purification. Promising membranes, identified based on their laboratory-scale performances, have been selected for onsite testing in industrial processes to validate their performances as well as stability and durability. Verified membranes are upscaled for pilot tests. This account paper summarizes MEMFO's research and development outcomes over the past decade and discusses our research strategies and perspectives for future work.
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In this study a thin film composite （TFC） membrane with a Pebax/Task-specific ionic liquid （TSIL） blend selective layer was prepared. Defect-flee Pebax/TSIL layers were coated successfully on a ...polysulfone ultrafiltration porous support with a poly- dimethylsiloxane （PDMS） gutter layer. Different parameters in the membrane preparation （e.g. concentration, coating time） were investigated and optimized. The morphology of the membranes was studied by scanning electron microscopy （SEM）, while the thermal properties and chemical structures of the membrane materials were investigated by thermo-gravimetric ana- lyzer （TGA）, differential scanning calorimetry （DSC） and Fourier transform infrared spectroscopy （FTIR）. The CO2 separation performance of the membrane was evaluated using a mixed gas permeation test. Experimental results show that the incorpora- tion of TSIL into the Pebax matrix can significantly increase both C02 permeance and CO2/N2 selectivity. With the presence of water vapor, the membrane exhibits the best CO2/N2 selectivity at a relative humidity of around 75%, where a CO2 permeance of around 500 GPU and a CO2/N2 selectivity of 46 were documented. A further increase in the relative humidity resulted in higher CO： permeance but decreased COIN2 selectivity. Experiments also show that CO2 permeance decreases with a CO2 partial pressure increase, which is considered a characteristic in facilitated transport membranes.
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