Tailoring the Separation Behavior of Hybrid Organosilica Membranes by Adjusting the Structure of the Organic Bridging Group
Tailoring the Separation Behavior of Hybrid Organosilica Membranes by Adjusting the Structure of the Organic Bridging Group
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DOI：
10.1002/adfm.201002361
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发表时间：
2011-06-21
影响因子：
19
通讯作者：
ten Elshof, Johan E.
中科院分区：
文献类型：
--
作者：
Castricum, Hessel L.;Paradis, Goulven G.;ten Elshof, Johan E.
有机连接硅杂化材料是一种极具应用前景的高效节能分子分离膜材料。其高稳定性允许在恶劣的工作条件下运行。本文报道了通过调整有机桥接基团的大小、柔韧性、形状和电子结构来调整这些杂化二氧化硅膜的分离性能。采用一种通用的方法，由不同反应活性的桥接硅氧烷前体合成纳米孔膜。具有短烷基烯（CH2和C2H4）桥接基团的膜具有高的H-2/N-2渗透率，这与分子大小的差异有关。较长的（C8H16）烷基烯和芳基桥得到了最高的CO2/H-2渗透率，这与材料中的吸附亲和力有关。具有长柔性亚烯桥的材料具有疏水性表面，并表现出强烈的温度依赖性分子运输以及在渗透蒸发过程中的高正丁醇通量，这表明了有机聚合物的性质。桥接基团的多功能性提供了一个广泛的工具箱来调整纳米结构和杂化二氧化硅膜的亲和力，并通过这样做来优化特定分离挑战的性能。这为碳捕获和生物燃料生产等工业应用提供了良好的前景。
Hybrid organically linked silica is a highly promising class of materials for the application in energy-efficient molecular separation membranes. Its high stability allows operation under aggressive working conditions. Herein is reported the tailoring of the separation performance of these hybrid silica membranes by adjusting the size, flexibility, shape, and electronic structure of the organic bridging group. A single generic procedure is applied to synthesize nanoporous membranes from bridged silsesquioxane precursors with different reactivities. Membranes with short alkylene (CH2 and C2H4) bridging groups show high H-2/N-2 permeance ratios, related to differences in molecular size. The highest CO2/H-2 permeance ratios, related to the affinity of adsorption in the material, are obtained for longer (C8H16) alkylene and aryl bridges. Materials with long flexible alkylene bridges have a hydrophobic surface and show strongly temperature-dependent molecular transport as well as a high n-butanol flux in a pervaporation process, which is indicative of organic polymerlike properties. The versatility of the bridging group offers an extensive toolbox to tune the nanostructure and the affinity of hybrid silica membranes and by doing so to optimize the performance towards specific separation challenges. This provides excellent prospects for industrial applications such as carbon capture and biofuel production.