A hybrid processing method for high performance hydrogen-selective silica membranes

Gopalakrishnan, Suraj; Yoshino, Yūji; Nomura, Mikihiro; Nair, Balagopal N.; Nakao, Shin Ichi

doi:10.1016/j.memsci.2007.03.034

Cited by 54 publications

(27 citation statements)

References 27 publications

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“…Microporous silica membranes with large surface areas on defect free gamma alumina intermediate layers and tubular alumina supports were prepared by ceramic extrusion method towards the preparation of substrate bundles for H 2 separation recently by Yoshino et al [9]. Rapid hybrid processing method comprised of sol-gel and CVD was used for the preparation of silica membranes on capillary substrates with gamma alumina intermediate layers (with 5 nm pore sizes) in order to improve the separation and permeation properties [10].…”

Section: Introductionmentioning

confidence: 99%

“…The number of comprehensive studies describing the design/characterization/stabilization of mesoporous cAl 2 O 3 membrane pore structures as well as their gas transport properties has increased significantly with the synthesis of stable boehmite sols over the past three decades [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. The pore structure characteristics, molecular properties of gaseous species and their interactions with the pore walls are some of the important factors for gaseous transport through porous membranes.…”

Section: Introductionmentioning

confidence: 99%

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Sol–gel derived mesoporous and microporous alumina membranes

Topuz

Çiftçioğlu

2010

J Sol-Gel Sci Technol

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Stable polymeric and colloidal boehmite sols were prepared by sol-gel process through controlled hydrolysis/condensation reactions. The particle sizes of the colloidal sols were in the 12-25 nm range depending on the process parameters and about 2 nm for polymeric sols. The presence of a significant increase in the microporosity content of the heat treated polymeric membranes relative to the mesoporous colloidal membranes might make the design of thermally stable microporous alumina membranes with controlled pore structures possible. The phase structure evolution in the 600-800°C range had shown that the crystallization of the gamma alumina in the amorphous matrix starts at about 800°C. This indicated that the pore structure stability may be enhanced through processing up to this relatively high temperature in polymeric alumina derived unsupported membranes. The permeance values of the two and three layered colloidal alumina membranes were observed to be independent of pressure which implies that the dominant gas transport mechanism is Knudsen diffusion in these structures. This was also supported by the 2.8 nm BJH pore sizes of the colloidal membranes. The Knudsen diffusion equation derived permeances of the polymeric alumina membranes with thicknesses of about 300 nm were determined to be very close to the experimentally determined permeance values.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sol–gel derived mesoporous and microporous alumina membranes

Topuz

Çiftçioğlu

2010

J Sol-Gel Sci Technol

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“…Using the TMOS/O 2 reaction system at 873 K, Gopalakrishnan et al [84] performed an extended modification of microporous calumina/silica membranes applying an opposing-reactants CVD configuration. After 2 h of CVD treatment H 2 and N 2 exhibited activated transport (E a,H2 = 19.4 kJÁmol À1 and E a,N2 = 8.54 kJ mol À1 ) with a relatively high permeation rate for H 2 (3.27 Â 10 À7 mol m À2 s À1 Pa À1 ) and low N 2 permeance (6.51 Â 10 À11 mol m À2 s À1 Pa À1 ).…”

Section: Resultsmentioning

confidence: 99%

Experimental investigation of the transport mechanism of several gases during the CVD post-treatment of nanoporous membranes

Labropoulos

Athanasekou

Kakizis

et al. 2014

Chemical Engineering Journal

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“…The defect was characterised with a permeability technique and a novel mercury intrusion. However, Gopalakrishnan et al (2007) applied a hybrid processing method for hydrogen-selective membrane preparation. They applied a primary sol-gel silica layer for the CVD zone thickness reduction, and a CVD modification with tetramethoxysilane (TMOS) and O 2 at 873 K. After which they only examined H 2 /N 2 selectivity to be 2300 at 873 K. Pejman et al (2011) modified the surface of ceramic supports to facilitate the deposition of defect-free overlying micro and mesoporous membrane.…”

Section: Introductionmentioning

confidence: 99%

Gas Permeation Study Using Porous Ceramic Membranes

Kajama¹,

Nwogu²,

Gobina³

2014

EER

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A 6000 nm ceramic membrane was repaired with boehmite solution (ALOOH) through the repeat dip-coating technique. The permeance of hydrogen (H 2 ) and carbon dioxide (CO 2 ) were obtained through the membrane in relation to average pressure at room temperature for the support membrane and as cracked membrane. A repair process was carried out on the cracked membrane by same dip coating process and results obtained after first and second dips. The permeance of the support membrane obtained ranged between 1.50 to 3.04 × 10 -7 mol m -2 s -1 Pa -1 . However, as a result of a crack that occurred during the removal of the membrane from the reactor, the permeance increased from 2.96 to 5.82 10 -7 mol m -2 s -1 Pa -1 . Further application of boehmite solution on the membrane lead to an improvement on the surface of the membrane with some degree and surface cracks were reduced. This also decreased the permeance to 1.26 -3.39 × 10 -8 mol m -2 s -1 Pa -1 after the second dip. Consequently, another silica based modified membrane was used for carbon dioxide and nitrogen (N 2 ) permeation. The plots show that carbon dioxide permeated faster than the other gases, indicating dominance of a more selective adsorptive transport mechanism. Accordingly, results obtained show an appreciable high carbon dioxide permeance of 3.42 × 10 -6 mol m -2 s -1 Pa -1 at a relatively low pressure when compared to nitrogen confirming that the membrane has so far exhibited a high permeability, selectivity and high CO 2 gas recovery. The permselectivities of CO 2 over H 2 at room temperature was also obtained which were higher than the Knudsen selectivity.

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A hybrid processing method for high performance hydrogen-selective silica membranes

Cited by 54 publications

References 27 publications

Sol–gel derived mesoporous and microporous alumina membranes

Sol–gel derived mesoporous and microporous alumina membranes

Experimental investigation of the transport mechanism of several gases during the CVD post-treatment of nanoporous membranes

Gas Permeation Study Using Porous Ceramic Membranes

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