Competitive permeation of gas and water vapour in high free volume polymeric membranes

Scholes, Colin A.; Jin, Jianyong; Stevens, Geoffrey W.; Kentish, Sandra E.

doi:10.1002/polb.23689

Cited by 54 publications

(89 citation statements)

References 50 publications

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“…The other fundamental parameters of the three pure membranes have already been reported in the literature and are provided in Table 4. The calculated mobility factor for Teflon AF1600 is comparable to literature, but that of 6FDA-TMPDA and PIM-1 are lower than that reported in the literature [7,15,25]. This implies that the 6FDA-TMPDA and PIM-1 membranes studied here have reduced interconnectivity between the micro-voids, which is attributed to the annealing temperature of the membranes.…”

Section: Single Gas Permeabilitysupporting

confidence: 78%

“…This difference is attributed to the low feed pressure, meaning the micro-voids are not saturated and hence the CO 2 solubility is greater than that observed for other studies undertaken at higher pressures [28]. The water permeability through PIM-1 is comparable to the author's previous study [7], and demonstrates that PIM-1 has selectivity for water over CO 2 . The Teflon AF1600 permeabilities are comparable with literature [15] and demonstrate the unique selectivity for CO 2 over H 2 O.…”

Section: Single Gas Permeabilitymentioning

confidence: 43%

“…The feed gas was 10% CO 2 in CH 4 mixture at 9.87 atm and 35 • C. The choice in single gas and mixed gas feed pressures were to ensure the membranes experience the same partial pressure of CO 2 under both single and mixed gas conditions. Vapor concentration polarization was not an issue for these polymeric membrane systems because of the low stage cut (<0.1), but to ensure good flow conditions the feed flowrate was at 100 mL/min and the helium sweep gas was at 24 mL/min, which are comparable to previous mixed gas with vapor studies [7]. Pure CO 2 (99.5% Industrial grade), pure CH 4 (99.9% High purity) and 10% CO 2 in CH 4 mixed gas where obtained from Coregas (Melbourne, Australia).…”

Section: Methodsmentioning

confidence: 55%

“…This also creates a problem in that glycol vapor entrained in the natural gas will also reduce the separation performance of downstream polymeric membranes [5]. Previous research has demonstrated that exposure to water vapor can reduce the permselectivity of the polyimide 6FDA-TMPDA by 50% [6] and for high performance PIM-1 membranes by 38% [7]. The majority of the research has focused on water removal from the feed stream, in dehydration applications [8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Water Resistant Composite Membranes for Carbon Dioxide Separation from Methane

Scholes

2018

Applied Sciences

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Abstract:Membranes that are resistant to water vapor permeation have potential in natural gas sweetening by reducing the need for pretreatment. The perfluorinated polymer Teflon AF1600 has proven resistance to water vapor, which is adapted here in the form of composite membranes consisting of a Teflon AF1600 protective layer on membranes of the polyimide 4,4 -(hexafluoroisopropylidene) diphthalic anhydride 2,3,5,6-tetramethyl-1,4-phenylenediamine (6FDA-TMPDA) as well as Polymer of Intrinsic Micro-porosity (PIM-1). The permeability of CO 2 and CH 4 through the composite membranes was shown to be a function of the respective permeabilities of the individual polymer layers, with the Teflon AF1600 layer providing the majority of the resistance to mass transfer. Upon exposure to water, the composite membranes had reduced water permeation of 7-13% compared to pure membranes of 6FDA-TMPDA and PIM-1, because of the water resistance of the Teflon AF1600 layer. It was observed that water permeated as clusters through the composite structure. Under CO 2 -CH 4 mixed gas conditions, 6FDA-TMPDA layer permselectivity performance was reduced and became comparable to Teflon AF1600, while the PIM-1 layer retained much of its high permselectivity performance. Importantly, at water activities below 0.2 the PIM-1 composite membrane achieved higher permeability for CO 2 compared to water.

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Section: Single Gas Permeabilitysupporting

confidence: 78%

Section: Single Gas Permeabilitymentioning

confidence: 43%

Section: Methodsmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

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Water Resistant Composite Membranes for Carbon Dioxide Separation from Methane

Scholes

2018

Applied Sciences

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“…Water vapor permeance increases at higher RH and TEG content. It is known that increase in water vapor permeance with increased RH is a common observation . In addition, the equilibrium water sorbability increases with higher RH and TEG content as shown in the isotherms portrayed in Figure (b).…”

Section: Resultsmentioning

confidence: 82%

Effect of hygroscopic materials on water vapor permeation and dehumidification performance of poly(vinyl alcohol) membranes

Bui

Wong

Thu

et al. 2017

J of Applied Polymer Sci

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In this study, two hygroscopic materials, inorganic lithium chloride (LiCl) and organic triethylene glycol (TEG) were separately added to poly(vinyl alcohol) (PVA) to form blend membranes for air dehumidification. Water vapor permeation, dehumidification performance and long‐term durability of the membranes were studied systematically. Membrane hydrophilicity and water vapor sorbability increased significantly with higher the hygroscopic material contents. Water vapor permeance of the membranes increased with both added hygroscopic material and absorbed water. Water permeation energy varied from positive to negative with higher hygroscopic content. This observation is attributed to a lower diffusion energy and a relatively constant sorption energy when hygroscopic content increases. Comparatively, PVA/TEG has less corrosive problems and is more environmentally friendly than PVA/LiCl. A membrane with PVA/TEG is observed to be highly durable and is suitable for dehumidification applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44765.

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Ultra‐High Proton/Vanadium Selectivity for Hydrophobic Polymer Membranes with Intrinsic Nanopores for Redox Flow Battery

Chae

Luo

Moon

et al. 2016

Advanced Energy Materials

133

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with Nafi on/SiO 2 hybrid membrane at the current density, 10 mA cm −2 . [ 10 ] Apart from the modifi cation of Nafi on membrane, the enhanced performances of VRB were recently also achieved with several kinds of sulfonated aromatic polymers in terms of the minimized hydrophilic domains. [11][12][13] Therefore, it is understood that the control of hydrophobic nature seems to be a common way to reduce the vanadium cross-over.More recently, Zhang et al. reported a VRB with a nanofi ltration type porous membrane that achieved competitive performances, a CE up to 95% and an EE of 76%. [ 14 ] The working principle has been based on the size sieving separation owing to the quite different size of proton and vanadium ions. [ 15 ] This strategy offers not only tremendously decreased cost owing to the already commercialized product, but also an ultimate insight toward maximizing H + /V selectivity. If the pore size of the membrane only enables protons (or water) transfer, the maximized performances could be achieved through the maximized H + /V selectivity. Thus, the subnano-sieving membrane for proton permselective transport is challenging. Here we report a fundamentally new concept to realize such proton/ vanadium selectivity. The concept is unprecedented as the material is hydrophobic, does not swell in water, contains micro porosity hosting water molecules along which protons can migrate and does not allow any other (vanadium) whatsoever. The proposed working principle of such hydrophobic polymers with intrinsic microporosity is disclosed in Scheme 1 .PIM-1 is the fi rst generation polymer having an intrinsic microporosity. We hypothesize that these materials can transport protons preferentially in VRBs because of its hydrophobic molecular structure, limited swelling in aqueous solution, inherent microporous structure with a pore diameter less than 2 nm, high free volume fraction above 20%, good solution processability, and relatively slow physical ageing compared to other high free volume polymers. [16][17][18] Even though hydrophobic, its microporosity is suspected to transport water molecules at high rates: Kentish and co-workers demonstrated water vapor permeation through PIM-1 at no fewer than 30 000 Barrer (1 Barrer = 10 −10 cm 3 (STP) cm (cm 2 s cm Hg) −1 ) above a water activity of 0.7. [ 19 ] Yet, little is known about the state of water inside such microporous polymers: one may anticipate the water being preferentially partitioned in the free-volume forming the microporosity rather than being absorbed into the polymer matrix. This could imply that a certain degree of proton transfer could occur by water molecules inside PIM-1. Meanwhile, the partitioning of hydro-solvated vanadium ions is expected to be limited by both the small radius of its pores and the difference of dielectric property, as illustrated in Scheme 1 .Recent increasing interest in the integration of renewable energy sources has accelerated efforts to develop electric energy storage (EES). [ 1,2 ] Among many approaches for EES, the allvanad...

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Competitive permeation of gas and water vapour in high free volume polymeric membranes

Cited by 54 publications

References 50 publications

Water Resistant Composite Membranes for Carbon Dioxide Separation from Methane

Water Resistant Composite Membranes for Carbon Dioxide Separation from Methane

Effect of hygroscopic materials on water vapor permeation and dehumidification performance of poly(vinyl alcohol) membranes

Ultra‐High Proton/Vanadium Selectivity for Hydrophobic Polymer Membranes with Intrinsic Nanopores for Redox Flow Battery

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