Bis(triethoxysilyl)ethane (BTESE)-derived silica membranes: pore formation mechanism and gas permeation properties
Bis(triethoxysilyl)ethane (BTESE)-derived silica membranes: pore formation mechanism and gas permeation properties
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DOI：
10.1007/s10971-018-4618-x
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发表时间：
2018-04-01
影响因子：
2.5
通讯作者：
Tsuru, Toshinori
中科院分区：
文献类型：
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作者：
Moriyama, Norihiro;Nagasawa, Hiroki;Tsuru, Toshinori
基于其在气相和液相分离方面的高性能，1,2-双（三乙氧基甲硅烷基）乙烷（BTESE）衍生的有机硅膜引起了广泛关注。为了提高性能，我们重点研究了溶胶制备中的酸摩尔比（AR）及其对溶胶-凝胶加工过程中孔隙形成机制的影响。制备了 AR = 10(-4)-10(0) 的 BTESE 衍生溶胶，并通过 FT-IR、核磁共振 (NMR)、N-2 吸附和正电子湮灭寿命 (PAL) 测量详细评估了 AR 对凝胶结构的影响。通过 FT-IR 和 NMR 证实了凝胶的化学结构，并表明具有最大数量硅烷醇基团 (AR = 10(-2)) 的溶胶在烧制过程中缩合显着增加。通过N-2吸附和PAL测量表征的烧制凝胶的多孔结构表明，AR = 10(-2)烧制凝胶由大量在烧制过程中形成的小孔组成。单一气体渗透实验显示出较高的H-2渗透性(5-9 x 10(-7) mol/(m(2) Pa s))和H-2/CF4选择性(700-20,000)。中间体 AR (=10(-2)) 的气体选择性渗透率（He/H-2、H-2/N-2 和 H-2/CF4）最高，这对应于未烧成凝胶中硅烷醇基团的最大含量，并证实在烧成过程中硅烷醇基团的缩合形成了小孔。[图表]。
Based on their high performance in gas and liquid-phase separations, 1,2-bis(triethoxysilyl)ethane (BTESE)-derived organosilica membranes have attracted much attention. To improve performance, we focused on the acid molar ratio (AR) in sol preparation and its effect on the pore formation mechanism during sol-gel processing. BTESE-derived sols with AR = 10(-4)-10(0) were prepared, and the effect of the AR on the gel structure was evaluated in detail via FT-IR, nuclear magnetic resonance (NMR), N-2 adsorption, and positron annihilation lifetime (PAL) measurements. The chemical structure of the gels was confirmed by FT-IR and NMR and showed that sols with the largest number of silanol groups (AR = 10(-2)) experienced a significant increase in condensation during the firing process. The porous structures of fired gels characterized by N-2 adsorption and PAL measurement showed that the AR = 10(-2) fired gel consisted of a larger number of small pores that had formed during the firing process. Single-gas permeation experiments showed high H-2 permeance (5-9 x 10(-7) mol/(m(2) Pa s)) and H-2/CF4 selectivity (700-20,000). The gas permselectivity (He/H-2, H-2/N-2, and H-2/CF4) was highest for the intermediate AR (=10(-2)), which corresponded to the greatest amount of silanol groups in unfired gels and confirmed that small pores had formed from the condensation of silanol groups during firing.[GRAPHICS].