- 學位論文
製備多孔性金屬有機骨架作為製冷吸附劑之研究
The Preparation of Porous Metal Organic Framework for Adsorption Chiller
摘要
本研究主要以二氧化矽添加金屬有機骨架化合物並經化學溶凝膠法製備出適用於製冷系統內之吸附劑，並藉由TGA、BET、XRD、SEM、EDX等相關儀器進行驗證，主要觀察吸附劑於相同添加比例下，經物理性混合與化學性溶凝膠混合對水氣吸附能力之差異、晶體變化及等溫吸附模式曲線等。由XRD結果可以看到該吸附劑經吸脫附的程序後其晶體結構及化學組成依然保持不變的。而在BET等溫吸附曲線結果得知該吸附劑的吸附曲線是屬於典型的Type Ⅳ型，其孔徑約為56Å屬於中孔型態。此外對吸附劑進行吸附/脫附(300C/950C)之循環測試可以得知在相同添加比例下，經化學溶凝膠法所製備之吸附劑其對水氣的吸附能力比物理混合所製備之吸附劑來的高，並在實驗中找到最佳的金屬有機骨架化合物添加於二氧化矽之比例。在添加比例為29.65%下經物理混合所製備之吸附劑對水氣的吸附量為0.639 gg-1，若改以化學溶凝膠法來製備則吸附劑對水氣的吸附量則可達0.99 gg-1。
並列摘要
In this study, the adsorbents for adsorption chiller were prepared by mixing the sol-gel silica with metal organic frameworks. The adsorbents are analyzed by TGA, BET, XRD, and SEM/EDX. Results show that the crystalline structure and chemical composition of the adsorbents remain the same before and after the adsorption and desorption cycles. The BET results indicate that the adsorption isotherm of these adsorbents belongs to Type Ⅳ mesopore adsorption behavior with the inner pore sizes of 56 Å. Furthermore, the water vapor uptake of the adsorbents in adsorption-desorption cycles (30 0C/95 0C) was measured. The water-uptake capability of the adsorbents prepared with various ratios of silica to metal organic framework was examined. Regarding to two different preparation schemes, the adsorbents synthesized by chemical sol-gel process always have higher magnitudes of water vapor uptake than that of the adsorbents prepared by physical mixing. When the mixing ratio of metal organic framework to silica reaches to 29.65%, the water vapor uptake of the adsorbent synthesized by physical mixing becomes 0.639gg-1, while that of the adsorbent synthesized by sol-gel process reaches 0.99 gg-1.