Synthesis, characterization and gas permeation properties of a silica membrane prepared by high-pressure chemical vapor deposition

Araki, Sadao; Mohri, Norito; Yoshimitsu, Yuichi; Miyake, Yoshikazu

doi:10.1016/j.memsci.2006.12.034

Cited by 73 publications

(50 citation statements)

References 17 publications

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“…Although correction of Knudsen flow was made in this study, the activation energy without correlation was approximately the same as that without correction when the permeance ratio was greater than 100, due to the small contribution of permeation through large pores. Figure 8 shows the permeance ratio of He/H 2 as a function of the activation energy of H 2 for microporous silica membranes prepared by sol-gel, 17,22 CVD, 24,[47][48][49] and vitreous silica 9 using various materials including silica and silica composite oxides with Zr, Ni, and Co. It should be noted Table 1.…”

Section: Permeation Of Hydrogen Through Silica Membranesmentioning

confidence: 99%

Permeation properties of hydrogen and water vapor through porous silica membranes at high temperatures

et al. 2011

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Silica and cobalt-doped silica membranes that showed a high permeance of 1.8 Â 10 À7 mol m À2 s À1 Pa À1 and a H 2 /N 2 permeance ratio of $730, with excellent hydrothermal stability under steam pressure of 300 kPa, were successfully prepared. The permeation mechanism of gas molecules, focusing particularly on hydrogen and water vapor, was investigated in the 300-500 C range and is discussed based on the activation energy of permeation and the selectivity of gaseous molecules. The activation energy of H 2 permeation correlated well with the permeance ratio of He/H 2 for porous silica membranes prepared by sol-gel processing, chemical vapor deposition (CVD), and vitreous glasses, indicating that similar amorphous silica network structures were formed. The permeance ratios of H 2 /H 2 O were found to range from 5 to 40, that is, hydrogen (kinetic diameter: 0.289 nm) was always more permeable than water (0.265 nm).

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Section: Permeation Of Hydrogen Through Silica Membranesmentioning

confidence: 99%

Permeation properties of hydrogen and water vapor through porous silica membranes at high temperatures

et al. 2011

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“…Experimentally, the super-conducting domains consist of pores with characteristic dimensions of the order of 1 nm or less. Silica films with a thickness of 30-100 nm accommodate these pores [28][29][30]. The gas molecules were found to selectively permeate thin film membranes via these pores, competing, in parallel, with Fickian transport in the poorly-diffusing domain [27].…”

Section: Introductionmentioning

confidence: 98%

Diffusive hydrogen inter-cage migration in hydrogen and hydrogen-tetrahydrofuran clathrate hydrates

Cao

English

MacElroy

2013

The Journal of Chemical Physics

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Classical equilibrium molecular dynamics simulations have been performed to investigate the diffusive properties of inter-cage hydrogen migration in both pure hydrogen and mixed hydrogen-tetrahydrofuran sII hydrates at 0.05 kbar from 200 K and up to 250–260 K. For mixed H2-THF systems in which there is single H2 occupation of the small cage (labelled “1S1L”), we found that no H2 migration occurs. However, for more densely filled H2-THF and pure-H2 systems, in which there is more than single H2 occupation in the small cage, there is an onset of inter-cage H2 migration events from the small cages to neighbouring cavities at around 200 K. The mean square displacements of the hydrogen molecules were fitted to a mathematical model consisting of an anomalous term and a Fickian component, and nonlinear regression fitting was conducted to estimate long-time (inter-cage) diffusivities. An approximate Arrhenius temperature relationship for the diffusion coefficient was examined and an estimation of the hydrogen hopping energy barrier was calculated for each system.

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“…The HT-CVD membrane showed a high hydrogen permeance on the order of 10 −7 mol m −2 s −1 Pa −1 with a H 2 /CH 4 selectivity above 1000 at 600 • C. The relatively high H 2 permeance and excellent selectivity of this CVD-derived silica membrane are due to its thinness (30-40 nm) and to a silica structure with pore sizes of about 0.3 nm. However, CVD-derived silica membranes show high hydrogen permselectivity but low hydrogen permeance, in general, because of the dense silica layer on a porous substrate [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Organic–inorganic hybrid silica membranes with controlled silica network size: Preparation and gas permeation characteristics

Kanezashi

Yada

Yoshioka

et al. 2010

Journal of Membrane Science

141

111

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Synthesis, characterization and gas permeation properties of a silica membrane prepared by high-pressure chemical vapor deposition

Cited by 73 publications

References 17 publications

Permeation properties of hydrogen and water vapor through porous silica membranes at high temperatures

Permeation properties of hydrogen and water vapor through porous silica membranes at high temperatures

Diffusive hydrogen inter-cage migration in hydrogen and hydrogen-tetrahydrofuran clathrate hydrates

Organic–inorganic hybrid silica membranes with controlled silica network size: Preparation and gas permeation characteristics

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