Enhanced propylene/propane separation by thermal annealing of an intrinsically microporous hydroxyl-functionalized polyimide membrane

Swaidan, Ramy J.; Ma, Xiaohua; Litwiller, Eric; Pinnau, Ingo

doi:10.1016/j.memsci.2015.08.015

Cited by 72 publications

(63 citation statements)

References 38 publications

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“…Freshly-cast films showed an increase in bulk density from 1.22 g/cm 3 for the 120 °C-dried film reported in [42] polyimides is known to be beneficial for their selectivity due to the formation of charge transfer complexes (CTCs) [51,52]. …”

Section: Thermal Annealing Of Pim-6fda-ohmentioning

confidence: 99%

High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide

Salinas

Litwiller

et al. 2016

Journal of Membrane Science

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106

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High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide, Journal of Membrane Science, http://dx.doi.org/10.1016/j.memsci. 2015.11.013 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractAn intrinsically microporous polymer with hydroxyl functionalities, PIM-6FDA-OH, was used as a precursor for various types of carbon molecular sieve (CMS) membranes for ethylene/ethane separation. The pristine polyimide films were heated under controlled N 2 atmosphere at different stages from 500 to 800 °C. All CMS samples carbonized above 600 °C surpassed the polymeric ethylene/ethane upper bound. Pure-gas selectivity reached 17.5 for the CMS carbonized at 800 °C with an ethylene permeability of about 10 Barrer at 2 bar and 35 °C, becoming the most selective CMS for ethylene/ethane separation reported to date. As expected, gravimetric sorption experiments showed that all CMS membranes had ethylene/ethane solubility selectivities close to 2 one. The permselectivity increased with increasing pyrolysis temperature due to densification of the micropores in the CMS membranes, leading to enhanced diffusivity selectivity. Mixed-gas tests with a binary 50:50 v/v ethylene/ethane feed showed a decrease in selectivity from 14 to 8.3 as the total feed pressure was increased from 4 to 20 bar. The selectivity drop under mixed-gas conditions was attributed to non-ideal effects: (i) Competitive sorption that reduced the permeability of ethylene and (ii) dilation of the CMS that resulted in an increase in the ethane permeability.

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Section: Thermal Annealing Of Pim-6fda-ohmentioning

confidence: 99%

High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide

Salinas

Litwiller

et al. 2016

Journal of Membrane Science

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106

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“…In many of these applications, membrane technologies are preferred over conventional separation techniques (e.g., distillation, absorption, and adsorption) due to their superior features such as [14][15][16][17]: (i) stable production with high separation efficiency [18]; (ii) low energy consumption with no phase change requirements [15,19]; (iii) simple operation with convenient modular scale-up [20][21][22]; and (iv) small environmental footprint [18,23]. Nevertheless, implementation of membrane technologies in practical applications has been limited by challenges with the engineering of robust materials able to be effective under a variety of operating conditions and environments [21,24], with only polymer membranes currently available in large-scale applications; yet failing to overcome Robeson's [25,26] trade-off curves between the selectivity and permeability [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Modeling Permeation through Mixed-Matrix Membranes: A Review

Monsalve-Bravo

Bhatia

2018

Processes

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Over the past three decades, mixed-matrix membranes (MMMs), comprising an inorganic filler phase embedded in a polymer matrix, have emerged as a promising alternative to overcome limitations of conventional polymer and inorganic membranes. However, while much effort has been devoted to MMMs in practice, their modeling is largely based on early theories for transport in composites. These theories consider uniform transport properties and driving force, and thus models for the permeability in MMMs often perform unsatisfactorily when compared to experimental permeation data. In this work, we review existing theories for permeation in MMMs and discuss their fundamental assumptions and limitations with the aim of providing future directions permitting new models to consider realistic MMM operating conditions. Furthermore, we compare predictions of popular permeation models against available experimental and simulation-based permeation data, and discuss the suitability of these models for predicting MMM permeability under typical operating conditions.

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“…Mixedgas permeation properties measured at 4 bar pressure and 35 °C with a 50:50 propylene/propane feed showed a drop in propylene permeability and C 3 H 6 /C 3 H 8 selectivity for both membrane types (open symbols, Figure 3b), most likely due to competitive sorption effects. 10,28,33 Nevertheless, the highest loading PIM-6FDA-OH/ZIF-8 (65 wt%) membrane maintained excellent mixed-gas performance with a propylene permeability of 30 barrer and C 3 H 6 /C 3 H 8 selectivity of ~31.…”

Section: Resultsmentioning

confidence: 99%

Highly Compatible Hydroxyl-Functionalized Microporous Polyimide-ZIF-8 Mixed Matrix Membranes for Energy Efficient Propylene/Propane Separation

Ma¹,

Swaidan

Wang³

et al. 2018

ACS Appl. Nano Mater.

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106

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Mixed-matrix membranes composed of mechanically strong, solution-processable polymers and highly selective ultramicroporous fillers (pore size < 7 Å) are superior candidate membrane materials for a variety of energy-intensive gas separation applications because of their structural tunability to achieve enhanced gas permeability and gas-pair selectivity. However, their industrial implementation has been severely hindered because inefficient compatibility of the polymer matrices and crystalline fillers results in poorly performing membranes with low filler capacity and interfacial defects. Herein, we report for the first time a unique strategy to fabricate highly propylene/propane selective mixed-matrix membranes (MMMs) composed of a hydroxyl-functionalized microporous polyimide (PIM-6FDA-OH) and an ultramicroporous, strongly size-sieving zeolitic imidazolate framework (ZIF-8). Excellent compatibility between PIM-6FDA-OH and ZIF-8 with selective filler loading up to 65 wt% resulted from N…O-H induced hydrogen bonding as evidenced by Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The newly developed MMMs demonstrated unprecedented mixed-gas performance for C 3 H 6 /C 3 H 8 separation and outstanding plasticization resistance of up to at least 7 bar feed pressure. The reported fabrication concept is expected to be applicable to a wide variety of OH functionalized polymers and alternative tailor-made imidazolate framework materials designed for MMMs to achieve optimal gas separation performance.

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Enhanced propylene/propane separation by thermal annealing of an intrinsically microporous hydroxyl-functionalized polyimide membrane

Cited by 72 publications

References 38 publications

High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide

High-performance carbon molecular sieve membranes for ethylene/ethane separation derived from an intrinsically microporous polyimide

Modeling Permeation through Mixed-Matrix Membranes: A Review

Highly Compatible Hydroxyl-Functionalized Microporous Polyimide-ZIF-8 Mixed Matrix Membranes for Energy Efficient Propylene/Propane Separation

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