Novel MOF‐Membrane for Molecular Sieving Predicted by IR‐Diffusion Studies and Molecular Modeling

Bux, Helge; Chmelik, Christian; Baten, J.M. van; Krishna, Rajamani; Caro, Jürgen

doi:10.1002/adma.201002066

Cited by 237 publications

(224 citation statements)

References 31 publications

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“…ZIF-8 is one of the first MOFs that were shown to be capable for molecular sieving, which refers to the ability to separate diffusing species based on subtle differences in molecular size and/or shape (203). Diffusivity data have been measured by macroscopic (uptake rate (198,203) and membrane permeation), mesoscopic (IR microscopy (204,205)), and microscopic (PFG-NMR (206)(207)(208)) methods. Results of macroscopic methods are shown in Figure 38, which is a comprehensive diffusion study (198) of 14 gases and vapors.…”

Section: Diffusion In a Prototypical Mofmentioning

confidence: 99%

Polymer Transport Properties

Koros

Burgess

Chen

2015

Encyclopedia of Polymer Science and Technology

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Section: Diffusion In a Prototypical Mofmentioning

confidence: 99%

Polymer Transport Properties

Koros

Burgess

Chen

2015

Encyclopedia of Polymer Science and Technology

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“…28À30 A number of ZIFs show excellent chemical and thermal stabilities, which is advantageous for membrane applications. ZIF-8 (Zn(mim) 2 , mim = 2-methylimidazolate) membranes 31,32 and ZIF-22 (Zn(5abim) 2 , 5abim = 5-azabenzimidazolate) membranes 33 were prepared by in situ crystallization, ABSTRACT: A highly oriented zeolitic imidazolate framework 8 (ZIF-8) composite membrane was prepared by seeding and secondary growth. By dip-coating, preformed ZIF-8 nanocrystals were attached to the surface of a porous R-alumina support using polyethyleneimine as the coupling agent.…”

Section: ' Introductionmentioning

confidence: 99%

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

et al. 2011

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In the past 10 years, porous metalÀorganic frameworks (MOFs) have established themselves in materials science. 1À3 The 3-D framework structures are formed by metal clusters or cations connected by organic linker molecules. On the basis of the organicÀinorganic hybrid character, MOFs have promise in a wide range of applications, e.g., gas storage, 4,5 medical applications, 6À8 catalysis, 9 sensor technology, 10,11 and molecular separation. 12À14 Basically, there are three options to use MOFs for molecular separation of liquid or gas mixtures: (i) by retaining one or more species from the liquid or gas phase by preferential adsorption in the pores, (ii) by different diffusivities of the species in the MOF, which is in the extreme case sterical size exclusion (molecular sieving) of one or more species, and (iii) the combination of (i) and (ii). One of the primary features that makes MOFs highly interesting for molecular separation is the so-called isoreticular design. 15 Linker molecules can be modified with functional groups or even completely substituted, maintaining the basic framework structure while altering adsorption and diffusion properties. 16 Membranes in general represent a cost and energy effective solution for industrial gas and liquid separation modified support. The mixture separation performance of membranes is characterized by the separation factor R i , j , which is defined after IUPAC as the ratio of the molar fraction of species i and j in the permeate, divided by the ratio of the molar fraction of species i and j in the retentate. 17 Currently, there are increasing numbers of successful attempts to prepare molecular sieving MOF membranes as thin, polycrystalline layers on top of macroporous support materials, showing separation factors up to 25. 18À27 For the preparation of MOF membranes, usually two basic techniques known from zeolite membrane fabrication are applied: (i) secondary growth crystallization, where in a first a step a seed layer is attached to the support and, subsequently, in a second step, grown to a continuous polycrystalline layer under solvothermal conditions, and (ii) in situ crystallization, where the polycrystalline layer is grown on the bare or chemically modified support in a one-step one-pot solvothermal synthesis. In situ crystallizations seem to be simple and, thus, the favored preparation route. However, they have the disadvantage of critically depending on high rates of heterogeneous nucleation on the support surface to successfully obtain continuous, well-intergrown MOF layers. Whether or not a high surface nucleation rate occurs depends on various factors, e.g., the surface chemistry of the support material (zeta potential, surface acidity, etc.). In secondary growth crystallizations, nucleation and crystal growth are decoupled, and hence, high nucleation rates and chemical interactions with the support material are less crucial.Recently, we reported on the preparation of ceramic-supported zeolitic imidazolate framework (ZIF) membranes. ZIF-type MOFs frequen...

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“…7,8 To predict adsorption behaviour for any given MOF, for example by molecular simulation, the nature and energetics of its structural response must first be measured and quantified. 9,10,[11][12][13] Structural changes of these types have been observed over a wide range of conditions in cases where significant guest uptakes occur, ranging from low temperatures and pressures 14 to room temperature and very high pressures. 15,16 At very high pressures, the PV energy term associated with the ingress of molecules from fluids into pores becomes comparable with typical energies of adsorption.…”

Section: Introductionmentioning

confidence: 99%

Pore Shape Modification of a Microporous Metal–Organic Framework Using High Pressure: Accessing a New Phase with Oversized Guest Molecules

et al. 2016

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Pressures up to 0.8 GPa have been used to squeeze a range of sterically 'oversized' C5-C8 alkane guest molecules into the cavities of a small-pore Sc-based metal-organic framework. Guest inclusion causes a pronounced reorientation of the aromatic rings of one third of the terephthalate linkers, which act as 'torsion springs', resulting in a fully reversible change in the local pore structure. The study demonstrates how pressure-induced guest uptake can be used to investigate framework flexibility relevant to 'breathing' behavior and to understand the uptake of guest molecules in MOFs relevant to hydrocarbon separation.

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Novel MOF‐Membrane for Molecular Sieving Predicted by IR‐Diffusion Studies and Molecular Modeling

Cited by 237 publications

References 31 publications

Polymer Transport Properties

Polymer Transport Properties

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation

Pore Shape Modification of a Microporous Metal–Organic Framework Using High Pressure: Accessing a New Phase with Oversized Guest Molecules

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Novel MOF‐Membrane for Molecular Sieving Predicted by IR‐Diffusion Studies and Molecular Modeling

Cited by 237 publications

References 31 publications

Polymer Transport Properties

Polymer Transport Properties

Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H2/C3H8 Molecular Sieve Separation

Pore Shape Modification of a Microporous Metal–Organic Framework Using High Pressure: Accessing a New Phase with Oversized Guest Molecules

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Oriented Zeolitic Imidazolate Framework-8 Membrane with Sharp H₂/C₃H₈ Molecular Sieve Separation