Redefining the Robeson upper bounds for CO2/CH4 and CO2/N2 separations using a series of ultrapermeable benzotriptycene-based polymers of intrinsic microporosity

Comesaña-Gándara, Bibiana; Chen, Jie; Bezzu, C. Grazia; Carta, Mariolino; Rose, Ian; Ferrari, Maria-Chiara; Esposito, Elisa; Fuoco, Alessio; Jansen, Johannes C.; McKeown, Neil B.

doi:10.1039/c9ee01384a

Cited by 595 publications

(475 citation statements)

References 61 publications

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“…For CO2/CH4 separation, the PEEK-WC-based MMMs show far superior properties than the Pebax ® -based membranes, which hardly change with the MOF concentration. A strong contribution of size selectivity between CO2 and the much bulkier CH4 molecules (Figure 7b) and a further increase [8,9]; yellow line 2015 [60]; purple line 2019 upper bound [61]. The arrows qualitatively indicate the direction of increasing MOF loading.…”

Section: Robeson's Plots and Performance Overviewmentioning

confidence: 94%

“…The gas transport properties for all membranes are summarized in the Robeson diagrams in Figure 9 for four gas pairs representing industrially important separations: CO2/N2, CO2/CH4, O2/N2 and H2/N2. upper bound [8,9]; yellow line 2015 [60]; purple line 2019 upper bound [61]. The arrows qualitatively indicate the direction of increasing MOF loading.…”

Section: Robeson's Plots and Performance Overviewmentioning

confidence: 99%

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Glassy PEEK-WC vs. Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi-MOF Based Mixed Matrix Membranes

et al. 2020

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Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so-called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance of two different MMMs, containing the metal-organic framework CuNi-MOF in the rubbery Pebax ® 1657 and in the glassy poly(ether-ether-ketone) with cardo moiety, PEEK-WC. The chemical and structural properties of MMMs were investigated by means of FT-IR spectroscopy, scanning electron microscopy and EDX analysis. The influence of MOF on the mechanical and thermal properties of both polymers was investigated by tensile tests and differential scanning calorimetry, respectively. The MOF loading in Pebax ® 1657 increased the ideal H 2 /N 2 selectivity from 6 to 8 thanks to an increased H 2 permeability. In general, the MOF had little effect on the Pebax ® 165 membranes because an increase in gas solubility was neutralized by an equivalent decrease in effective diffusivity. Instead, the addition of MOF to PEEK-WC increases the ideal CO 2 /CH 4 selectivity from 30 to~48 thanks to an increased CO 2 permeability (from 6 to 48 Barrer). The increase in CO 2 permeability and CO 2 /CH 4 selectivity is maintained under mixed gas conditions. natural gas treatment (CO 2 /CH 4 ) [6], and post-combustion carbon capture from flue gas (CO 2 /N 2 ) [7]. This increasing interest is dictated by the advantages of membrane technology compared to traditional gas separation techniques. Gas separation by means of membrane technology is an economical process; it is easily scalable and it can be used in non-drastic temperature and pressure conditions, which are more environmentally friendly. Despite numerous efforts to develop new materials for gas separation, the membrane market still needs to overcome some challenges. In fact, the highly permeable rubbery polymers present low selectivity, and the highly-selective glassy polymers are less permeable. To overcome this trade-off between permeability and selectivity, extensively reported by Robeson in 1991 and in 2008 [8,9], researchers are focusing on the design and development of hybrid membranes based on the combination of two different materials in order to get the advantages of both [10]. According to this concept, a valid strategy is the embedding of porous metal-organic frameworks (MOFs) in the polymer matrix in order to obtain mixed matrix membranes (MMMs) with enhanced gas transport properties [11][12][13][14][15][16]. MOFs are an attractive new class of microporous materials built by the combination o...

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Section: Robeson's Plots and Performance Overviewmentioning

confidence: 94%

Section: Robeson's Plots and Performance Overviewmentioning

confidence: 99%

Glassy PEEK-WC vs. Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi-MOF Based Mixed Matrix Membranes

et al. 2020

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“…[4] Compared to pressure swing adsorption (PSA) and fractional/cryogenic distillation, membrane separation is considered a promising process owing to its low energy requirements, low investment cost, and easy operation. [5] The membranes for H 2 /CO 2 separation from coalderived syngas are expected to have a high H 2 /CO 2 selectivity at elevated temperature in the presence of water vapor. This is of critical importance for the pre-combustion capture of CO 2 after the water gas shift reaction where water is always present.…”

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confidence: 99%

Cross‐Linking between Sodalite Nanoparticles and Graphene Oxide in Composite Membranes to Trigger High Gas Permeance, Selectivity, and Stability in Hydrogen Separation

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Thin membranes (900 nm) were prepared by direct transformation of infiltrated amorphous precursor nanoparticles, impregnated in a graphene oxide (GO) matrix, into hydroxy sodalite (SOD) nanocrystals. The amorphous precursor particles rich in silanols (Si−OH) enhanced the interactions with the GO, thus leading to the formation of highly adhesive and stable SOD/GO membranes via strong bonding. The cross‐linking of SOD nanoparticles with the GO in the membranes promoted both the high gas permeance and enhanced selectivity towards H2 from a mixture containing CO2 and H2O. The SOD/GO membranes are moisture resistance and exhibit steady separation performance (H2 permeance of about 4900 GPU and H2/CO2 selectivity of 56, with no degradation in performance during the test of 50 h) at high temperature (200 °C) under water vapor (4 mol %).

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“…In contrast, PIM-EA(Me 2 )-TB has greater permeability than PIM-EA(H 2 )-TB. [21], 2008 [23], 2015 [24], and 2019 [25].…”

Section: Membrane Preparation and Gas Permeability Measurementsmentioning

confidence: 99%

“…The advancements in membrane technology convinced Robeson to revisit his studies in 2008 [23] when upper bounds were revised to accommodate new high performing polymers. Upper bounds were further updated for several gas pairs by Pinnau et al in 2015 [24], and by Comesaña-Gándara et al in 2019 [25]. The revisions were prompted by the development of Polymers of Intrinsic Microporosity (PIMs) [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Effect of Bridgehead Methyl Substituents on the Gas Permeability of Tröger’s-Base Derived Polymers of Intrinsic Microporosity

et al. 2020

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A detailed comparison of the gas permeability of four Polymers of Intrinsic Microporosity containing Tröger’s base (TB-PIMs) is reported. In particular, we present the results of a systematic study of the differences between four related polymers, highlighting the importance of the role of methyl groups positioned at the bridgehead of ethanoanthracene (EA) and triptycene (Trip) components. The PIMs show BET surface areas between 845–1028 m2 g−1 and complete solubility in chloroform, which allowed for the casting of robust films that provided excellent permselectivities for O2/N2, CO2/N2, CO2/CH4 and H2/CH4 gas pairs so that some data surpass the 2008 Robeson upper bounds. Their interesting gas transport properties were mostly ascribed to a combination of high permeability and very strong size-selectivity of the polymers. Time lag measurements and determination of the gas diffusion coefficient of all polymers revealed that physical ageing strongly increased the size-selectivity, making them suitable for the preparation of thin film composite membranes.

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Redefining the Robeson upper bounds for CO₂/CH₄ and CO₂/N₂ separations using a series of ultrapermeable benzotriptycene-based polymers of intrinsic microporosity

Abstract: Ultrapermeable benzotriptycene-based PIMs show exceptional gas selectivities that define new positions for the CO2/CH4 and CO2/N2 Robeson upper bounds.

Cited by 595 publications

References 61 publications

Glassy PEEK-WC vs. Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi-MOF Based Mixed Matrix Membranes

Glassy PEEK-WC vs. Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi-MOF Based Mixed Matrix Membranes

Cross‐Linking between Sodalite Nanoparticles and Graphene Oxide in Composite Membranes to Trigger High Gas Permeance, Selectivity, and Stability in Hydrogen Separation

Effect of Bridgehead Methyl Substituents on the Gas Permeability of Tröger’s-Base Derived Polymers of Intrinsic Microporosity

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