功能化magadiite基异质结构的制备及性能研究

发布时间：2018-04-23 23:41

  本文选题：magadiite + 超大微孔-介孔　； 参考：《北京化工大学》2015年硕士论文

【摘要】：二维层状粘土材料因其良好的离子交换性、吸附性及层间膨胀性而广泛应用于催化、吸附及新型功能材料领域。本文以自制的纯硅基粘土水合硅酸钠麦羟硅钠石(magadiite)为主体,采用共表面活性剂导向二维层间TEOS原位水解-缩聚法制备了magadiite基多级孔异质结构(PMH)。以PMH为基质,采用后嫁接铝法合成系列铝掺杂PMH催化剂,使用XRD、SEM/EDS、HRTEM、BET、27Al和29Si MAS NMR、 NH3-TPD与吡啶FT-IR等表征系统研究催化剂的结构、组成、形貌与表面酸性,深入探讨催化剂的傅-克烷基化活性。以十六烷基三甲基铵根(CTMA+)插层magadiite为基体,首次采用层间嫁接法制备出罗丹明B修饰magadiite基"OFF-ON"荧光传感器并研究其裸眼检测Hg2+-性能。论文的主要结论与创新点如下：(1)通过共模板剂导向TEOS在二维粘土magadiite层间原位水解-缩聚法制备了多级孔magadiite基异质结构(PMH)；层间介孔氧化硅与粘土层板的有机结合使PMH材料兼具超大比表面积(729 m2/g)、高的热稳定性及独特的超大微孔-介孔结构(0.80-1.96nm)。分别采用PMH后嫁接铝法和Al-magadiite前体法制备出铝掺杂PMH催化剂(xAl-PMH, x为Al/Si摩尔比,x=0.2、0.4、0.6、)和Al-magadiite基多级孔异质结构(PAMH, Al/Si摩尔小学=0.03)催化剂。xAl-PMH保持了良好的层状超大微孔-介孔多级孔结构(0.78-1.90±0.02 nm)和大的比表面积(282 m2/g),铝主要以四面体形式嫁接于PMH层间硅骨架内,显示出强的Lewis酸性与新生成的Bronsted酸性,而PMH仅有极弱的Lewis酸性。PAMH中铝则以层状骨架外八面体铝为主,因而导致了略微提高的Lewis酸性和微量Bronsted酸性。(2)以邻苯二酚(CAT)与叔丁醇(TBA)液相傅-克烷基化为目标反应考察催化剂的活性。优化的反应条件为反应温度138℃、TBA/CAT投料摩尔比2.0、反应时间4小时。在最优实验条件下,0.4A1-PMH给出了高达93.4%的CAT转化率、最高的对叔丁基邻苯二酚(4-TBC)选择性(80.4%)及最高的4-TBC收率(75.1%),归因为该催化剂较大的比表面积、最小的微孔体积和最多的表面Bronsted酸性位及其与保持良好的层状超大微孔-介孔结构间的强协同效应。(3)以CTMA+插层magadiite为基体,以罗丹明B-乙二胺内酰胺衍生物SRhB与异氰酸酯丙基三乙氧基硅烷反应得到的SRhB-IPTS为荧光探针,采用层间嫁接法将不同含量的SRhB-IPTS固载在CTMA-maga上,制备出新型罗丹明B修饰,magadiite基"OFF-ON"荧光传感器(SRhB-maga-X,X为SRhB-IPTS/CTMA-maga投料摩尔比,X=1或6、)。(4) SRhB-maga-6显示出较优的裸眼检测Hg2+性能,可在2分钟内检测出Hg2+,检测限为6.2×10-7M,并且对Hg2+检测性能在pH 5.0-12.0范围内不受环境pH干扰。SRhB-maga-6可从包括碱金属、碱土金属、第一周期过渡金属和重金属的多种金属离子中选择性识别Hg2+。使用过的SRhB-maga-6可在四丙基氢氧化铵溶液中简便再生、重复使用。该新型荧光传感器优异的Hg2+检测性能归因为其高的荧光探针SRhB-IPTS含量及其与基体以Si-O-Si键有序的链接和开阔的层间通道。
[Abstract]:Two-dimensional layered clay materials are widely used in catalysis, adsorption and new functional materials due to their good ion exchange, adsorption and interlaminar expansion. In this paper, magadiite based multilevel pore heterostructure was prepared by co-surfactant guided two-dimensional TEOS in-situ hydrolysis-Polycondensation method, based on self-made silicon-based clay hydrated sodium silicate sodium silicate. A series of Al-doped PMH catalysts were synthesized by post-grafting aluminum method with PMH as the substrate. The structure, composition, morphology and surface acidity of the catalysts were studied by using XRD-SEM- EDM / EDSE-HRTE-BET-27Al and 29Si MAS NMRs, NH3-TPD and pyridine FT-IR. The activity of catalyst for Friedel-g alkylation was discussed. Using cetyltrimethylammonium trimethylammonium (magadiite) intercalated magadiite as substrate, Rhodamine B modified magadiite based "OFF-ON" fluorescence sensor was prepared by interlaminar grafting for the first time, and its open-eye detection of Hg2-was studied. The main conclusions and innovations of this paper are as follows: (1) TEOS was synthesized by in-situ hydrolysis-Polycondensation method of two-dimensional clay magadiite, and the organic combination of interlaminar mesoporous silica and clay laminates resulted in the synthesis of multilevel porous magadiite based heterostructure by in-situ hydrolysis-Polycondensation method. The PMH materials have a high specific surface area of 729m2 / g / g, high thermal stability and unique ultra-large microporous mesoporous structure of 0.80-1.96nmm. Aluminum-doped PMH catalyst (x = Al/Si molar ratio, x = Al/Si = 0.2n 0.4U 0.6G) and Al-magadiite based multilevel pore heterostructure (Pam H, Al/Si Mohr 0.03) were prepared by PMH and Al-magadiite precursor methods respectively. The catalyst. XAl-PMH kept a good layer super large micropore and many mesoporous pores. The mesoporous structure is 0.78-1.90 卤0.02 nm) and the large specific surface area is 282 m2 / g / g. Aluminum is grafted mainly in the form of tetrahedron into the PMH interlaminar silicon skeleton. The results showed that the strong acidity of Lewis and the acidity of newly formed Bronsted showed that the aluminum in PMH was mainly octahedral aluminum with outer layered skeleton, which was only very weak in Lewis acidity. This led to a slight increase in the acidity of Lewis and a slight increase in the acidity of Bronsted. The activity of the catalyst was investigated by focusing on the liquid-phase Friede-gram alkylation of catechol (catechol) with tert-butanol (TBA). The optimum reaction conditions were as follows: reaction temperature 138 鈩，

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