Fabrication and Evaluation of Trimethylmethoxysilane (TMMOS)-Derived Membranes for Gas Separation

Mise, Yoshihiro; Ahn, So-Jin; Takagaki, Atsushi; Kikuchi, Ryuji; Oyama, S. Ted

doi:10.3390/membranes9100123

Cited by 8 publications

(16 citation statements)

References 36 publications

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“…(2) ν*, the vibrational frequency should be higher for the permeate gas having the smaller molecular weight, i.e., ν* for H2 (2.02 g mol −1 ) > ν* for He (4.00 g mol −1 ). As shown in Table 2, the values of NS and ν* estimated for He and H2 permeations through the PCS(UH) corresponded to the physical constants mentioned above, and similar to those previously reported for the membranes composed of SiOC (#01) [45] or SiO2 (#02 ~ 05) [41,42,46,47].…”

Section: Analysis Of Gas Permeation Behaviors (1) He and H2 Permeationssupporting

confidence: 87%

“…The fitting parameters obtained in this study were listed in Table 2, and compared with those for H2-selective amorphous ceramic membranes previously reported by other research groups: polysiloxanederived amorphous silicon oxycarbide (SiOC) membrane (#01) synthesized by pyrolysis at 700 • C in Ar [45], and CVD-derived SiO2 membranes (#02 ~ 05) having different microporosity which Oyama et al [41,42,46,47] systematically synthesized by varying the organic ligand of starting Si alkoxide precursor and CVD process temperature in Ar: #02 [46] and #03 [41] (tetraethoxysilane (TEOS) at 600 • C), #04 (vinyltriethoxysilane (VTES) at 600 • C) [42], #05 (35% trimethylmethoxysilane (TMMOS) -TEOS at 650 • C) [47].…”

Section: Analysis Of Gas Permeation Behaviors (1) He and H2 Permeationsmentioning

confidence: 75%

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Superhydrophobic polycarbosilane membranes for purification of solar hydrogen

Kubo

Okibayashi

Kojima

et al. 2021

Separation and Purification Technology

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Superhydrophobic membranes composed of an organic-inorganic hybrid polymer, namely polycarbosilane (PCS) with Mw of 4-8.9 ×10 3 , were formed on a mesoporous γ-Al 2O3-modified α-Al2O3 porous support. Under dry condition at 50 • C, the supported PCS membranes exhibited H2 permeance of 1.1-1.6 ×10 −6 mol⋅m −2 ⋅s −1 ⋅Pa −1 and H2/N2 selectivity of 9.7-12.6 together with unique H2/He selectivity of 1.4-1.6. Even under saturated humidity at 50 • C, H2 permeance remained at 7.7 ×10 −8 mol −1 m −2 s −1 Pa −1 with improved H2/N2 selectivity of 26. Moreover, when the measurements were performed using a H2-N2 (2:1) mixed feed gas as a simulated syngas produced by novel solar hydrogen production systems, the H2 permeance almost unchanged, while the N2 permeance was below the limit of detection. These results revealed a great potential of PCSs to develop novel H 2selective membranes for purifying solar hydrogen under high-humidity conditions around 50 • C. Further study on the gas permeation behaviors of He, H2 and N2 suggested that the enhanced H2/N2 selectivity under the highhumidity conditions could be explained by the synergistic effect of preferential H 2 permeation through the dense PCS network governed by the solid state diffusion mechanism and blockage of N 2 permeation through micropore channels within the PCS network by the permeate H2O-induced plugging at around the hetero interface between the superhydrophobic PCS and highly hydrophilic γ-Al 2O3.

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Section: Analysis Of Gas Permeation Behaviors (1) He and H2 Permeationssupporting

confidence: 87%

Section: Analysis Of Gas Permeation Behaviors (1) He and H2 Permeationsmentioning

confidence: 75%

Superhydrophobic polycarbosilane membranes for purification of solar hydrogen

Kubo

Okibayashi

Kojima

et al. 2021

Separation and Purification Technology

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“…Thus, the observed E a values for He and H 2 permeations could depend on the density of the AHPCS-derived SiCH organic–inorganic hybrid network. However, a unique point was that, regardless of the synthesis temperature, the E a for H 2 permeation was found to be smaller than that for He permeation, which was a clear contrast to those evaluated for the H 2 -selecitve microporous amorphous silica membranes [ 10 , 11 , 65 , 66 , 67 ]. Then, an attempt was made for study on the hydrogen affinity of the AHPCS-derived SiCH organic–inorganic hybrid: The amount of H 2 adsorption on the AHPCS-derived SiCH film was measured by using a quartz-crystal microbalance (QCM).…”

Section: Resultsmentioning

confidence: 67%

“…However, under the given operating conditions [ 5 , 6 , 8 ], it is difficult to apply conventional H 2 -selective membranes, which require higher operation temperatures, approximately above 90, 180 and 350 °C for polymer [ 9 ], silica [ 10 , 11 , 12 ] and metal membranes [ 13 , 14 , 15 ], respectively. There are also technical issues such as water-induced swelling for polymer membranes, lower H 2 permeance for supported liquid membranes [ 16 , 17 , 18 ] and gas permeability degradation for intrinsically hydrophilic silica-based membranes [ 8 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Selective SiCH Inorganic–Organic Hybrid/γ-Al2O3 Composite Membranes

et al. 2020

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Solar hydrogen production via the photoelectrochemical water-splitting reaction is attractive as one of the environmental-friendly approaches for producing H2. Since the reaction simultaneously generates H2 and O2, this method requires immediate H2 recovery from the syngas including O2 under high-humidity conditions around 50 °C. In this study, a supported mesoporous γ-Al2O3 membrane was modified with allyl-hydrido-polycarbosilane as a preceramic polymer and subsequently heat-treated in Ar to deliver a ternary SiCH organic–inorganic hybrid/γ-Al2O3 composite membrane. Relations between the polymer/hybrid conversion temperature, hydrophobicity, and H2 affinity of the polymer-derived SiCH hybrids were studied to functionalize the composite membranes as H2-selective under saturated water vapor partial pressure at 50 °C. As a result, the composite membranes synthesized at temperatures as low as 300–500 °C showed a H2 permeance of 1.0–4.3 × 10−7 mol m−2 s−1 Pa−1 with a H2/N2 selectivity of 6.0–11.3 under a mixed H2-N2 (2:1) feed gas flow. Further modification by the 120 °C-melt impregnation of low molecular weight polycarbosilane successfully improved the H2-permselectivity of the 500 °C-synthesized composite membrane by maintaining the H2 permeance combined with improved H2/N2 selectivity as 3.5 × 10−7 mol m−2 s−1 Pa−1 with 36. These results revealed a great potential of the polymer-derived SiCH hybrids as novel hydrophobic membranes for purification of solar hydrogen.

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“…Notable past work includes the original papers [9,10], the use of sol-gel techniques [11,12], chemical vapor deposition (CVD) [13,14] and plasma methods [15,16], the employment of diverse CVD precursors [17][18][19][20][21] and compositions [22][23][24], the determination of porosity [25], and the elucidation of the mechanism of permeation [26][27][28]. Important precedents are the use of dimethyldimethoxysilane (DMDMOS) [17] and other methyl-substituted siloxanes [29,30].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Silica Membranes by Chemical Vapor Deposition Using a Dimethyldimethoxysilane Precursor

et al. 2020

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Silica-based membranes prepared by chemical vapor deposition of tetraethylorthosilicate (TEOS) on γ-alumina overlayers are known to be effective for hydrogen separation and are attractive for membrane reactor applications for hydrogen-producing reactions. In this study, the synthesis of the membranes was improved by simplifying the deposition of the intermediate γ-alumina layers and by using the precursor, dimethyldimethoxysilane (DMDMOS). In the placement of the γ-alumina layers, earlier work in our laboratory employed four to five dipping-calcining cycles of boehmite sol precursors to produce high H2 selectivities, but this took considerable time. In the present study, only two cycles were needed, even for a macro-porous support, through the use of finer boehmite precursor particle sizes. Using the simplified fabrication process, silica-alumina composite membranes with H2 permeance > 10−7 mol m−2 s−1 Pa−1 and H2/N2 selectivity >100 were successfully synthesized. In addition, the use of the silica precursor, DMDMOS, further improved the H2 permeance without compromising the H2/N2 selectivity. Pure DMDMOS membranes proved to be unstable against hydrothermal conditions, but the addition of aluminum tri-sec-butoxide (ATSB) improved the stability just like for conventional TEOS membranes.

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Fabrication and Evaluation of Trimethylmethoxysilane (TMMOS)-Derived Membranes for Gas Separation

Cited by 8 publications

References 36 publications

Superhydrophobic polycarbosilane membranes for purification of solar hydrogen

Superhydrophobic polycarbosilane membranes for purification of solar hydrogen

Hydrogen Selective SiCH Inorganic–Organic Hybrid/γ-Al2O3 Composite Membranes

Synthesis of Silica Membranes by Chemical Vapor Deposition Using a Dimethyldimethoxysilane Precursor

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