Microporous organic polymers for carbon dioxide capture

High-performance polymeric membranes for gas separation are attractive for molecular-level separations in industrial-scale chemical, energyand environmental processes. Molecular sieving materials are widely regarded as the next-generation membranes to simultaneously achieve high permeability and selectivity. However, most polymeric molecular sieve membranes are based on a few solution-processable polymers such as polymers of intrinsic microporosity. Here we report an in situ cross-linking strategy for the preparation of polymeric molecular sieve membranes with hierarchical and tailorable porosity. These membranes demonstrate exceptional performance as molecular sieves with high gas permeabilities and selectivities for smaller gas molecules, such as carbon dioxide and oxygen, over larger molecules such as nitrogen. Hence, these membranes have potential for large-scale gas separations of commercial and environmental relevance. Moreover, this strategy could provide a possible alternative to 'classical' methods for the preparation of porous membranes and, in some cases, the only viable synthetic route towards certain membranes.

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“…4b This further confirms that the molecular sieving effect is responsible for the extraordinary membrane-separation performance (Fig. 4c) 36 .…”

Section: Resultssupporting

confidence: 71%

Polymeric molecular sieve membranes via in situ cross-linking of non-porous polymer membrane templates

et al. 2014

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“…As it was described in our previous study [40], the shape of these isotherms provides information about the porosity of the samples. The performance of the HTC derived ACs are similar to ACs with similar development of porosity, and also is comparable with related porous solids found in the literature [41] and with other type of porous materials, such as microporous organic polymers [42]. The same three HTC derived ACs tested as CO 2 adsorbents were also studied as materials for high pressure CH 4 storage.…”

Section: Co 2 and Ch 4 Storage Using The Htc-derived Acssupporting

confidence: 56%

Tailoring the porosity of chemically activated hydrothermal carbons: Influence of the precursor and hydrothermal carbonization temperature

Falco

Marco-Lozar

Salinas-Torres

et al. 2013

Carbon

216

131

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Advanced porous materials with tailored porosity (extremely high development of microporosity together with a narrow micropore size distribution (MPSD)) are required in energy and environmental related applications. Lignocellulosic biomass derived HTC carbons are good precursors for the synthesis of activated carbons (ACs) via KOH chemical activation. However, more research is needed in order to tailor the microporosity for those specific applications. In the present work, the influence of the precursor and HTC temperature on the porous properties of the resulting ACs is analyzed, remarking that, regardless of the precursor, highly microporous ACs could be generated. The HTC temperature was found to be an extremely influential parameter affecting the porosity development and the MPSD of the ACs. Tuning of the MPSD of the ACs was achived by modification of the HTC temperature. Promising preliminary results in gas storage (i.e. CO 2 capture and high pressure CH 4 storage) were obtained with these materials, showing the effectiveness of this synthesis strategy in converting a low value lignocellulosic biomass into a functional carbon material with high performance in gas storage applications. IntroductionHydrothermal Carbonization (HTC) is now a well-established thermochemical synthesis alternative to produce functional carbon materials with a tunable chemical structure from pure carbohydrates or lignocellulosic biomass [1][2][3].During HTC, biomass-derived precursors are converted into valuable carbon materials using water as reaction medium at mild temperatures (< 200°C) under self-generated pressures [4]. Even though this methodology has been known for almost 100 years [5], its full potential, as a synthetic route for carbon materials having important applications in several fields such as catalysis, energy storage, CO 2 sequestration, water purification, soil remediation, has been revealed only recently, mainly via the work of Dr. Titirici and coworkers [6].Under hydrothermal conditions monosaccharides are dehydrated to 5-hydroxymethylfurfural (5-HMF) via the well-known Lobry de Bruyn-Alberta van Ekstein rearrangement [7]. Once 5-HMF is formed, it is in situ "polymerised" yielding the HTC carbon product [8]. While most of the research efforts focus on the exploitation of HMF for the production of chemicals, bioplastics and biofuels [9], the Titirici´s group rediscovered these processes for the production of green and valuable carbon and carbon-hybrid materials [1,4].One of the main limiting factors, hindering the effective and straightforward exploitation of HTC carbons for several end-applications (eg. catalysis, separation science, energy production and storage), is their low surface area and porosity [10]. In the case of monosaccharide derived HTC carbons, this problem has been elegantly overcome by using hard\soft-templating strategies or by addition of structural directing agents [11][12][13]. Such synthetic routes are effective because of the homogeneous nature of the pre-HTC aqueous reaction mixt...

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“…Benzimidazole-linked polymers 41 show selectivities up to 113 at 273 K, being reduced to 71 at 298 K. Although nitrogen-rich organic cage frameworks 30,47 show high CO 2 /N 2 selectivities up to 213 at 298 K, their surface areas (o10 m 2 g À 1 ) and CO 2 capture capacities (up to 7.15 mg g À 1 ) are very low. Other structures with protic nitrogens also behave in a similar fashion 43,44,48 .…”

Section: Synthesismentioning

confidence: 85%

“…Owing to the presence of an electron-deficient carbon atom, CO 2 is expected to interact with protic electronegative functionalities (for example, amines) leading to a strong chemisorption, while N 2 remains impartial. So far, this simple interaction has led to a plethora of nanoporous polymers where the nitrogen-rich functionalities, such as triazine 1,18 , tetrazole 3 , imidazole 41 , phosphazene 24 , imide 42 and amines 25,43 , are built in. In all these and many other situations 2 , CO 2 -philicity is the main driving force for the CO 2 /N 2 selectivity, without taking into account any chemical architecture that would repel N 2 molecules selectively.…”

Section: Synthesismentioning

confidence: 99%

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

et al. 2013

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Post-combustion CO 2 capture and air separation are integral parts of the energy industry, although the available technologies remain inefficient, resulting in costly energy penalties. Here we report azo-bridged, nitrogen-rich, aromatic, water stable, nanoporous covalent organic polymers, which can be synthesized by catalyst-free direct coupling of aromatic nitro and amine moieties under basic conditions. Unlike other porous materials, azo-covalent organic polymers exhibit an unprecedented increase in CO 2 /N 2 selectivity with increasing temperature, reaching the highest value (288 at 323 K) reported to date. Here we observe that azo groups reject N 2 , thus making the framework N 2 -phobic. Monte Carlo simulations suggest that the origin of the N 2 phobicity of the azo-group is the entropic loss of N 2 gas molecules upon binding, although the adsorption is enthalpically favourable. Any gas separations that require the efficient exclusion of N 2 gas would do well to employ azo units in the sorbent chemistry.

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Microporous organic polymers for carbon dioxide capture

Cited by 562 publications

References 61 publications

Polymeric molecular sieve membranes via in situ cross-linking of non-porous polymer membrane templates

Polymeric molecular sieve membranes via in situ cross-linking of non-porous polymer membrane templates

Tailoring the porosity of chemically activated hydrothermal carbons: Influence of the precursor and hydrothermal carbonization temperature

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

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