親水性鋁金屬有機骨架之快速合成及吸水應用

Abstract

在現今主流的有機金屬骨架(Metal-Organic Framework, MOF)合成策略中，都有一個步驟是將MOF孔洞內的溶劑移除，藉由此步驟可以提昇MOF原本的結晶性。因此本論文想探討在MOF的合成過程中是否需要如同文獻中記載得那麼長的合成時間。並更進一步去探討，去除MOF中的溶劑是否能促使無續化的材料轉變成節晶化的才料。本論文選用作為研究目標的為鋁金屬的方形微孔MOF，分別為MIL-160、MIL-53-TDC、CAU-23和MOF-303。移除溶劑的方法為加熱抽真空(Heat Under Vacuum, HEAV)，藉由高溫真空的環境使溶劑脫去並觸發MOF的結構變化。為了驗證加熱抽真空的效果，本論文將大幅縮短反應時間合成出無序化的初合成材料，並且藉由回流反應將溫度拉高至溶劑沸點加速結晶化的過程。實驗中將MOF分成三個階段並利用PXRD觀察，分別為初合成、溶劑清洗後跟加熱抽真空後，從這三個階段的變化觀察到MOF在經過加熱抽真空後從先前的幾乎無序化轉變成了具有結晶性的材料。為了能夠確保極短時間合成出的MOF依然具有如同文獻記載的應用性，本論文分別做了氮氣比表面積及孔徑(Surface Area and Porosimetry Analyzer)的分析、材料外觀的分析(SEM)、熱穩定性的分析(TGA)、水分子的吸脫附測試及產重的統計。根據分析的結過發現極短時間合成的MOF依然保有如同文獻記載的比表面積及熱穩定性。在水分子吸脫附的分析中也依然具有如同文獻般良好的表現，且低分壓的等溫梯度吸附水分子可以應用在乾燥的沙漠中。在此便成功的大幅縮短MOF的反應時間且依然保有MOF原先的應用性。In the current mainstream Metal-Organic Framework (MOF) synthesis strategies, there is a step to remove the solvent in the MOF pores, and this step can improve the original crystallinity of the MOF. Therefore, in this paper, we want to explore whether the synthesis time of MOF is required as long as that recorded in the literature. And to further explore whether the removal of the solvent in the MOF can promote the transformation of amorphous materials to crystalline materials.In this paper, the square microporous MOF of aluminum metal is selected as the research target, namely MIL-160, MIL-53-TDC, CAU-23 and MOF-303. The method of removing the solvent is Heat Under Vacuum (HEAV), which removes the solvent and triggers the structural transformation of the MOF in a high-temperature vacuum environment. In order to verify the effect of heating and vacuuming, this article will greatly shorten the reaction time to synthesize the disordered primary synthesis material, and increase the temperature to the boiling point of the solvent by reflux reaction to accelerate the crystallization process. In the experiment, the MOF was divided into three stages and observed by PXRD. They were as-synthesis, solvent washed, and heat under vacuuming. From the changes in these three stages, it was observed that the MOF was almost disordered from the previous one after heat under vacuuming. into a crystalline material.In order to ensure that the MOF synthesized in a short time still has the same applicability as those described in the literature, there use the surface area and pore size analyze, SEM, TGA, water adsorption/desorption test and product weight on different reaction time. According to the analysis results, it is found that the MOF synthesized in a very short time still retains the specific surface area and thermal stability as described in the literature. In the analysis of water molecule adsorption /desorption, it still has a good performance as in the literature, and the low partial pressure isotherm gradient adsorption of water molecules can be applied in dry deserts. Here, the reaction time of MOF was successfully shortened and the original applicability of MOF was still maintained.