離子液體作用下溶膠—凝膠法合成介孔材料的研究
發(fā)布時間:2018-06-16 18:02
本文選題:溶膠-凝膠 + 離子液體 ; 參考:《天津大學(xué)》2015年碩士論文
【摘要】:介孔材料因具有規(guī)則的周期性孔道結(jié)構(gòu)、高度均一且相對較大的孔徑(2-50 nm)、較大的孔體積、高的比表面積及孔結(jié)構(gòu)可調(diào)等特性,使其在催化、吸附分離、生物醫(yī)藥合成等領(lǐng)域有著廣泛的應(yīng)用。離子液體因其具有界面張力低、良好的熱穩(wěn)定性、液態(tài)范圍寬、雙親性、可形成廣泛的氫鍵而具有良好的超分子結(jié)構(gòu)等特性,近年來被廣泛應(yīng)用于材料合成領(lǐng)域。本文以二取代咪唑類離子液體為模板合成介孔氧化硅和介孔氧化鋁材料,并最終得到了具有不同形貌和不同孔結(jié)構(gòu)的介孔氧化硅和介孔氧化鋁,在此基礎(chǔ)上還對離子液體合成介孔材料的模板作用機(jī)理進(jìn)行了深入研究。對于介孔氧化硅的合成,采用溶膠-凝膠法,以正硅酸乙酯(TEOS)為硅源、鹽酸為催化劑,重點(diǎn)考察了模板劑用量和種類對合成的介孔氧化硅的孔結(jié)構(gòu)及形貌的調(diào)控作用。研究結(jié)果表明:在介孔結(jié)構(gòu)調(diào)控方面,分別以離子液體[Bmim]Tfo、[Bmim]Cl和[Bmim]PF_6單獨(dú)為模板合成了具有蠕蟲狀介孔的氧化硅材料;分別以離子液體[Bmim]Tfo、[Bmim]Cl和[Bmim]PF_6和P123共模板合成了具有雙介孔結(jié)構(gòu)的高度有序介孔氧化硅;在形貌調(diào)控方面,以離子液體[Dmim]Cl為模板合成了空心球狀氧化硅,以[Dmim]Cl與P123共模板合成了管狀氧化硅,其管壁為高度有序介孔。對于介孔氧化鋁的合成,采用溶膠-凝膠法,以異丙醇鋁為鋁源,考察了不同介質(zhì)、模板劑種類及用量、煅燒溫度等對介孔結(jié)構(gòu)及氧化鋁形貌的影響。研究結(jié)果表明:在水介質(zhì)中,以離子液體[Bmim]PF_6為模板劑合成了有序的介孔氧化鋁;在乙醇介質(zhì)中,采用不同離子液體([Bmim]PF_6、[Bmim]Tfo、[Bmim]Cl、[Dmim]Cl、[C16mim]Cl)為模板均可獲得具有棒狀形貌的介孔氧化鋁。研究發(fā)現(xiàn)離子液體的用量對氧化鋁形貌的形成起著關(guān)鍵的作用。在實驗基礎(chǔ)上,還從微觀角度深度揭示了離子液體模板以及離子液體-表面活性劑共模板合成介孔材料的誘導(dǎo)作用機(jī)理,對介孔材料形貌及孔結(jié)構(gòu)的調(diào)控具有理論指導(dǎo)意義。
[Abstract]:Mesoporous materials are characterized by regular periodic pore structure, highly uniform and relatively large pore size (2-50 nm), large pore volume, high specific surface area and adjustable pore structure. Biomedical synthesis and other fields have been widely used. Ionic liquids with low interfacial tension, good thermal stability, wide liquid range, amphiphilic properties, can form a wide range of hydrogen bonds and have good supramolecular structure, and have been widely used in the field of material synthesis in recent years. In this paper, mesoporous silica and mesoporous alumina were synthesized by using disubstituted imidazole ionic liquids as templates. Finally, mesoporous silica and mesoporous alumina with different morphologies and different pore structures were obtained. On the basis of this, the mechanism of template action in the synthesis of mesoporous materials by ionic liquids was also studied. For the synthesis of mesoporous silica, the effect of the amount and type of template on the pore structure and morphology of the synthesized mesoporous silica was investigated by sol-gel method, using tetraethyl orthosilicate (TEOS) as silicon source and hydrochloric acid as catalyst. The results show that the mesoporous silica materials with wormlike mesoporous structure have been synthesized by using ionic liquid [Bmim] Tfol, [Bmim] Cl and [Bmim] PF6 as templates, respectively. Highly ordered mesoporous silica with double mesoporous structure was synthesized by co-templates of ionic liquid [Bmim] Tfol, [Bmim] Cl and [Bmim] PF6 and P123, respectively. Tubular silicon oxide was synthesized by co-template of [Dmim] Cl and P123. The tube wall is highly ordered mesoporous. For the synthesis of mesoporous alumina, the effects of different media, type and amount of template and calcination temperature on the mesoporous structure and morphology of alumina were investigated by sol-gel method and aluminum isopropanol as aluminum source. The results show that the ordered mesoporous alumina is synthesized by using ionic liquid [Bmim] PF6 as template in aqueous medium, and mesoporous alumina with rod-like morphology can be obtained by using different ionic liquids ([Bmim] PF6, [Bmim] Tfol, [Bmim] Cl, [Dmim] Cl, [C16mim] Cl) as templates in ethanol medium. It is found that the amount of ionic liquid plays a key role in the formation of alumina morphology. On the basis of the experiments, the inductive mechanism of the synthesis of mesoporous materials by ionic liquid template and ionic liquid-surfactant co-template was also revealed from the microcosmic point of view, which is of theoretical significance for the regulation of the morphology and pore structure of mesoporous materials.
【學(xué)位授予單位】:天津大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2015
【分類號】:TB383.4;O645.1
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