以回應曲面法探討溶膠-凝膠法製備奈米二氧化矽之參數影響

Analysis of the Parameters in a Sol-Gel Process for Preparing SiO2 Nanoparticles Using Response Surface Methodology

王惠君(Hui-Chun Wang)

指導教授 ： 鍾財王

中原大學/工學院/化學工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400275

摘要

本研究利用矽化四乙酯（TEOS）以溶膠-凝膠法來合成奈米二氧化矽，其中，針對反應組成物（TEOS、NH3、H2O、溶劑）和反應條件（溫度、時間）分別作討論，發現到二氧化矽顆粒的大小都會受其改變而改變；當TEOS、NH3的濃度減少，反應溫度增加，粒子大小會隨之變小，而隨著水的濃度增加粒子大小則會有先升後降的現象，溶劑方面，會因其介電常數值的上升而使合成出來的二氧化矽粒子粒徑較小；粒徑分佈方面，NH3、H2O的濃度增加會得到較均一的顆粒大小。由此得知，欲合成奈米級的二氧化矽，需將TEOS、H2O、NH3的濃度降低，選擇在較高的反應溫度下進行，且不宜選用介電常數較低的溶劑；本實驗中以TEOS=0.05 mole、H2O=0.55 mole、NH3=0.26 mole，以乙醇當作溶劑，60℃下反應時，可成功的合成出奈米級的二氧化矽（粒徑21.32nm），比表面積為774.41 m2/g。
最後藉由統計法中的回應曲面法，來了解特定參數（NH3濃度、H2O濃度、反應溫度）對目標函數（粒徑大小）的重要性，結果顯示此三項因子對粒徑大小有顯著影響，而NH3的濃度對粒徑分佈有較明顯的效應。

關鍵字

回應曲面法 ； 二氧化矽 ； 粒徑分佈 ； 溶膠-凝膠法 ； 奈米

並列摘要

SiO2 nanoparticles were prepared from tetraethylortho-silicate (TEOS) by using a sol-gel process. The effects of composition of reactants and reaction conditions were discussed. It was found that the size of silica nanoparticles would be changed with those parameters. Basically, particle size would be increase with the TEOS and NH3 concentrations, but decreased with the reaction temperature. Furthermore, particle size increased with water concentration at lower concentration levels of water; however, it decreased with water concentrations at higher concentration levels of water. Particle size would also become bigger because of the lower dielectric constant of solvent. Besides, with the increasing of NH3 and water concentrations, particle size distribution was more uniform. Hence, in order to prepare SiO2 nanoparticles, it is the better way to limit the concentration of TEOS, NH3 and water, and don’t choose a solvent with lower dielectric constant. Higher reaction temperature also favors to synthesize SiO2 nanoparticles. In this study, the synthesis conditions for preparing SiO2 nanoparticles (21.32 nm) were found to be TEOS=0.05 mole, NH3=0.23 mole, H2O=0.55 mole, reaction temperature=60℃ .
The response surface methodology (RSM) was also used to analyze the effect of parameters (NH3, water, reaction temperature) on the response variables (particle size and particle size distribution). We observed that these three parameters were all remarkable to the response variable of particle size. Nevertheless, NH3 concentration was more remarkable to the particle size distribution.

並列關鍵字

response surface methodology ； sol-gel process ； SiO2 ； nano ； particle size distribution

參考文獻

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