Microporous Inorganic Membranes

Yue, Lin; Kumakiri, Izumi; Nair, Balagopal N.; Alsyouri, Hatem M.

doi:10.1081/spm-120017009

Cited by 266 publications

(195 citation statements)

References 245 publications

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“…Those usually comprise a nonzeolitic support layer and a polycrystalline zeolite film (intergrown grains) that may be covered by an amorphous silica layer depending on the postsynthesis treatment. 19,20 In this context, it is worth mentioning that Caro and Noack have reviewed recent developments and progress of such zeolite membranes. 21 There is still a lack of knowledge with respect to the molecular structure of the surface of zeolite crystals.…”

Section: Methodsmentioning

confidence: 99%

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

2009

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With the aid of molecular simulation techniques (molecular dynamics, grand-canonical Monte Carlo, and reactive flux correlation function RFCF), the influence of the external surface on the equilibrium permeation of methane and ethane into and out of an AFI-type zeolite crystal has been studied. In particular, "extended dynamically corrected transition state theory", which has been proven to describe the transport of tracers in periodic crystals correctly, has been applied to surface problems. The results suggest that the molecules follow paths that are close to the pore wall in the interior and also at the crystal surface. Moreover, the recrossing rate at the surface turns out to be non-negligible, yet, in contrast to the intracrystalline recrossing rate, remains almost constant over loading which gives indication to diffusive barrier crossing at the crystal surface. As a consequence of very different adsorption and desorption barriers, the corresponding permeabilities are shown to be not equal for one and the same condition (T and p). The critical crystal length, beyond which surface effects can be certainly neglected, is computed on basis of flux densities. Entrance/exit effects, in the present cases, are practically important solely for ethane at low pressures. The influence of the type of external surface on the surface flux is, hereby, rather small, because the transport at the surface is controlled by the slow supply from the gas phase. This has been evidenced by a simplified thermodynamic model that has been derived within this work and which is based on rapidly assessable simulation data. Finally, we propose a procedure for estimating the importance of different factors that have an impact on surface effects.

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Section: Methodsmentioning

confidence: 99%

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

2009

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“…Most often, the studies have focused on the synthesis of continuous, intergrown polycrystalline thin films on top of a porous support by direct or in situ hydrothermal synthesis [6]. The main limitations of this method arise from the formation of heterogeneous badly intergrown films, as well as from nutrient depletion due to preferential growth of zeolite crystals in the bulk solution [4]. These shortcomings translate in practice into the need to use several synthesis cycles to ensure the growth of well-intergrown zeolite layers.…”

Section: Introductionmentioning

confidence: 99%

“…Zeolite membranes supported on ceramic supports have been largely proposed as promising candidates for gas separation and pervaporation applications [1][2][3][4]. Among these membranes, two families are particularly interesting for gas separation: -MFI-type membranes for high-temperature separation of linear and branched paraffin isomers by molecular-sieving [5][6][7][8], -FAU-type membranes for CO 2 separation in pre-and post-combustion applications, as well as in the purification of natural gas and biogas.…”

Section: Introductionmentioning

confidence: 99%

Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO₂Capture

Rouleau¹,

Pirngruber²,

Guillou³

et al. 2009

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Membranes nanocomposites MFI-alumine et FAU-alumine : synthèse, caractérisation & application à la séparation de paraffines et à la capture du CO 2 -Dans ce travail, nous rapportons la préparation de membranes nanocomposites MFI-alumine et FAU-alumine de haute surface (24-cm 2 ), thermiquement et mécaniquement résistantes, par synthèse de zéolithe dans les macropores de supports tubulaires en alumine α. Les membranes MFI ont été préparées à partir de mélange de précurseurs de type solution claire de manière à facilement pénétrer dans les pores du support. Les membranes MFI ont été évaluées en séparation de mélanges n-/i-butane. La fiabilité des synthèses a été améliorée par une agitation modérée. Les membranes MFI les plus sélectives ont été obtenues pour des supports avec des tailles moyennes de pores de 0,2 et 0,8 μm. L'épaisseur effective de MFI a pu être réduite à moins de 10 μm par imprégnation du support avec de l'eau avant la synthèse et par dilution du mélange de synthèse. La meilleure membrane MFI offre un excellent compromis entre sélectivité et perméance à 448 K, avec des facteurs de séparation pour les mélanges n-butane/i-butane jusqu'à 18 et des perméances du n-butane en mélange aussi élevées que 0,7 μmol⋅s -1 ⋅m -2 ⋅Pa -1 . Par ailleurs, une nouvelle architecture de membrane nanocomposite FAU a été obtenue par une voie de synthèse originale incluant un ensemencement in situ à partir d'un mélange refroidi de précurseur de type gel, suivi de croissance de la FAU par synthèse hydrothermale en deux étapes avec une solution claire de faible viscosité. Cette nouvelle membrane a montré des performances intéressantes en séparation de mélange équimolaire CO 2 /N 2 à 323 K, avec des facteurs de séparation CO 2 /N 2 et des perméances de CO 2 en mélange jusqu'à 12 et 0,4 μmol⋅s -1 ⋅m -2 ⋅Pa -1 , respectivement.Abstract -Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO 2 Capture -In this work, we report the preparation of thermally and mechanically resistant high-surface (24-cm 2 ) nanocomposite MFI-alumina and FAUalumina membranes by pore-plugging synthesis inside the macropores of α-alumina multilayered

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“…The discussion is limited to ''hybrid'' organosilica membranes, i.e., 3D bonded networks containing :Si-O-Si: and :Si-RSi: groups with homogeneous dispersion of both types of bonds on the atomic scale. For a review of the sol-gel processing of amorphous microporous silica and organically modified silica membranes, the reader is referred to other sources [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

Elshof

Dral

2015

J Sol-Gel Sci Technol

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Supported microporous organosilica membranes made from bridged silsesquioxane precursors by an acid-catalyzed sol-gel process have demonstrated a remarkable hydrothermal stability in pervaporation and gas separation processes, making them the first generation of ceramic molecular sieving membranes with sufficient performance under industrially relevant conditions. The commercial availability of various a,x-bis(trialkoxysilyl)alkane and 1,4-bis(trialkoxysilyl)benzene precursors facilitates the tailoring of membrane properties like pore size and surface chemistry via the choice of precursor(s) and process variables. Here, we describe the engineering of sols for making supported microporous thin films, discuss the thermal and hydrothermal stability of microporous organosilicas and give a short overview of the developments and applications of these membranes in liquid and gas separation processes since their first report in 2008.Graphical Abstract

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Microporous Inorganic Membranes

Cited by 266 publications

References 245 publications

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO₂Capture

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

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Microporous Inorganic Membranes

Cited by 266 publications

References 245 publications

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

On the Effects of the External Surface on the Equilibrium Transport in Zeolite Crystals

Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO2Capture

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

Contact Info

Product

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Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO₂Capture