Supercritical fluid extraction of a nonionic surfactant template from SBA-15 materials and consequences on the porous structure
Supercritical fluid extraction of a nonionic surfactant template from SBA-15 materials and consequences on the porous structure
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DOI：
10.1021/la026970c
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发表时间：
2003-04-29
期刊：
影响因子：
3.9
通讯作者：
Iglesias, J
中科院分区：
文献类型：
--
作者：
van Grieken, R;Calleja, G;Iglesias, J
采用Zhao等报道的方法合成了SBA-15介孔材料。通过不同的技术从所制备的材料中去除表面活性剂：在空气气氛下的热处理、在不同温度下的溶剂洗涤以及在存在和不存在共溶剂的情况下的超临界CO2萃取。使用常规技术表征所得材料的结构：氮和氩吸附测量、粉末X射线衍射（XRD）、热重分析（TGA）、红外光谱（FT-IR）和Si-29 MAS NMR。在超临界条件下使用CO2去除表面活性剂的效率类似于通过回流下的溶剂洗涤获得的效率，但在共溶剂的存在下显示出一些改进。中温溶剂萃取SBA-15材料的介观性质取决于表面活性剂去除效率和超临界CO2作为溶剂的使用。同样地，在处理的材料中检测到的互补微孔的尺寸和体积与在合成过程中去除在SBA-15中间相的硅质壁内封闭的三嵌段共聚物模板的亲水性聚（环氧乙烷）链的策略密切相关。
SBA-15 mesoporous materials were synthesized using the method reported by Zhao et al. Surfactant was removed from as-made materials by means of different techniques: thermal treatment under air atmosphere, solvent washing at different temperatures, and supercritical CO2 extraction in the presence and absence of cosolvents. The structure of resulting materials was characterized using conventional techniques: nitrogen and argon adsorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR), and Si-29 MAS NMR. The efficiency of surfactant removal using CO2 under supercritical conditions is similar to that obtained by means of solvent washing under reflux but shows some improvements in the presence of cosolvents. Mesoscopic properties of mild-temperature solvent extracted SBA-15 materials depend on the efficiency of the surfactant removal and the use of supercritical CO2 as solvent. Likewise, the size and volume of the complementary microporosity detected in the treated materials is closely related to the strategy of removal of hydrophilic poly(ethyleneoxide) chains of the triblock copolymer template occluded within the siliceous walls of the SBA-15 mesophase during the synthesis.