本文選題：氧化硅整體材料　切入點：正硅酸乙酯　出處：《哈爾濱理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：二氧化硅整體材料是一類具有三維網(wǎng)狀孔道結(jié)構(gòu)的新穎塊狀材料，其外觀形貌由合成的模具決定。根據(jù)制備工藝的不同，其孔道可由大孔、介孔與微孔中的一種或幾種組成。在整體材料中各種孔道的存在有利于傳質(zhì)，，減小背壓，骨架結(jié)構(gòu)使柱體具有一定的機械強度，孔道內(nèi)表面的大量硅羥基便于其它各種官能團的修飾與錨定，這使得其在色譜分離中展現(xiàn)出獨特的優(yōu)勢。近年來二氧化硅整體材料在催化劑領(lǐng)域得到了一些示范性的應(yīng)用。然而目前的制備過程復(fù)雜，通常使用的硅源為有機硅源，價格較為昂貴，限制了其在工業(yè)中的應(yīng)用。因此，研究使用廉價的硅酸鈉代替常用的有機硅源合成二氧化硅整體材料，并探討一種簡捷的干燥方式保持柱體形貌，這些具有一定的現(xiàn)實意義。 本文分別探討了使用正硅酸乙酯(TEOS)和硅酸鈉兩種物質(zhì)為硅源，在醋酸做催化劑，聚乙二醇(PEG)做為相分離引發(fā)劑的情況下，采用溶膠凝膠法合成二氧化硅整體材料。同時考察了水浴溫度、聚乙二醇含量、pH值、水含量及干燥條件等因素對二氧化硅整體材料孔道結(jié)構(gòu)、外觀形貌產(chǎn)生的影響。結(jié)果表明，在TEOS-PEG體系內(nèi)最佳制備條件為按照質(zhì)量比為TEOS:PEG:H2O:冰醋酸=1:0.09:1.90:0.26的實驗配比在40℃水浴條件下反應(yīng)24h。在硅酸鈉-PEG體系，最佳方案為硅酸鈉：聚乙二醇：蒸餾水：冰醋酸的質(zhì)量比為1:0.10:1.67:1.40，在50℃下恒溫18h。合成的二氧化硅整體材料經(jīng)掃描電子顯微鏡表明均具有連續(xù)的孔道結(jié)構(gòu)。XRD衍射結(jié)果表明產(chǎn)物中的骨架結(jié)構(gòu)主要由無定型二氧化硅組成。熱重分析說明了在不同溫度下材料的失重情況，而且在550℃下煅燒材料能有效的除去體系內(nèi)的PEG。 在應(yīng)用方面，將二氧化硅整體材料用C18修飾后對其吸油性能進行初步研究，并對比了兩種體系合成的材料在吸油性能上的差異。結(jié)果表明，形貌完好的二氧化硅整體材料能將染色的油膜吸附干凈。在與油滴的接觸角測試中，兩類體系的產(chǎn)品接觸角均為30°，說明二氧化硅整體材料與油是浸潤狀態(tài)，在實驗過程中能吸附水面油膜。
[Abstract]:Silica monolithic material is a kind of novel bulk material with three-dimensional reticular pore structure, the appearance of which is determined by the synthetic mould. One or more of the components of mesoporous and micropores. The existence of various channels in the whole material is conducive to mass transfer, reducing back pressure, and the skeleton structure makes the cylinder have a certain mechanical strength. The large amount of silica hydroxyl group on the inner surface of the pore is convenient for the modification and anchoring of other functional groups. In recent years, silica monolithic materials have been used in the field of catalysts. However, the preparation process is complex, and the silicone source is usually used as organic silicon source. Therefore, the use of cheap sodium silicate instead of common organic silicon sources to synthesize silicon dioxide monolithic materials was studied, and a simple drying method to maintain the shape of the cylinder was discussed. These have certain realistic significance. In this paper, the use of tetraethyl orthosilicate (TEOS) and sodium silicate as silicon sources, using acetic acid as catalyst and polyethylene glycol (PEG) as phase separation initiator were studied. Silica monolithic materials were synthesized by sol-gel method. The effects of water bath temperature, polyethylene glycol content, pH value, water content and drying conditions on the pore structure and appearance of silica monolithic materials were investigated. The optimum preparation conditions in TEOS-PEG system were as follows: TEOS: PEG: H2O: 1: 0.09: 1.90: 0.26. Under the water bath condition of 40 鈩

本文編號：1603819