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Title: | 開發與探究金屬有機骨架薄膜應用於氣體分離與純化 Development and Elucidation of Metal-Organic Framework Membranes for Gas Separation and Purification |
Authors: | 張宗鎧 Chung-Kai Chang |
Advisor: | 康敦彥 Dun-Yen Kang |
Keyword: | 薄膜分離,金屬有機骨架,薄膜氣體分離,混合官能基金屬有機骨架,層狀金屬有機骨架, Membrane-based separation,Metal-organic framework,Gas separation,Mixed-linker metal-organic framework,Two-dimensional metal-organic framework, |
Publication Year : | 2023 |
Degree: | 博士 |
Abstract: | 現今工業中使用的氣體分離程序,如:蒸餾、吸收與吸附等,以上程序大多會損耗大量的能源以達到分離純化之目的。根據過去的研究顯示,薄膜分離技術有望逐漸取代現今高耗能的氣體分離程序。金屬有機骨架(Metal-Organic Framework, MOF)是一種藉由金屬離子與有機配體配位形成具規則性網狀結構的孔洞材料。再者,多數MOF材料具有超微孔尺度(孔徑< 0.7 nm)的分離孔道,且現今工業中常需要進行分離純化的氣體分子大多坐落於0.2 - 0.6 nm的尺度,因此MOF相當具有應用於分離氣體潛力。本論文中,我們成功利用二次成長法合成出低缺陷之CAU-10-PDC薄膜。雖然我們發現CAU-10-PDC具有良好的H2/CH4與CO2/CH4之分離效能,但於長時間單一氣體與混合氣體量測中,我們卻發現其效能不穩定之結果。後續,我們藉由臨場(in situ) X-ray diffraction (XRD) 與Rietveld refinement技術分析結構資訊。而我們發現CAU-10-PDC材料在通入甲烷下會出現結構變形之現象,故導致氣體分離效能不穩定之結果。於是我們提出了混合官能基方法,藉由混摻不同比例之官能基調控其孔道性質,以增加其穩定性並同時提高CAU-10-PDC之分離效能。此外,我們利用1H-nuclear magnetic resonance (NMR)、Fourier transform infrared (FT-IR) 與elemental analysis (EA)等三個分析方法定量實際混摻官能基比例。我們也利用模擬方法分析不同比例之CAU-10-PDC-H之pore limiting diameter (PLD) 大小。在混合官能基薄膜的氣體分離量測中,我們發現CAU-10-PDC-H(7:3)具有高CO2通透率 (>1000 Barrer),並且其CO2/N2與CO2/CH4分離選擇率能夠高於50。同時,我們也利用長時間操作測試、in situ XRD與in situ diffuse reflectance infrared Fourier transform (DRIFT) 等三個實驗發現,當CAU-10-PDC-H之PDC:BDC比例為7:3時,其能夠同時具有良好的分離效能與穩定性。最後,我們藉由調控CAU-10-PDC-H(7:3)合成參數,並結合界面活性劑輔助方法,成功製備出CAU-10 奈米層狀材料,期望能藉此提升材料整體效能且增加其未來發展性。我們另藉由Maxwell equation預測混摻MOF於不同高分子基材所形成之mixed-matrix membrane (MMM)之分離效能,以供後續研究參考。 There is a growing need for alternatives to energy-intensive processes in the face of ongoing environmental and energy crises. Membrane-based separations have emerged as a potential solution due to their ability to selectively permit the passage of certain gases while retaining others. Metal-organic frameworks (MOFs) are a promising class of materials for gas separation applications due to their ultra-microporous structures. In this study, we synthesized defect-free CAU-10-PDC membranes using a secondary growth technique known as the seed-growth method. Although CAU-10-PDC exhibited high ideal selectivity for H2/CH4 and CO2/CH4 separations, its performance was found to be unstable during long-term gas permeation tests and mixed-gas separation experiments. We employed in situ X-ray diffraction (XRD) and Rietveld refinement to determine that the structure of CAU-10-PDC was deformed in a methane atmosphere, leading to the observed instability in its performance. To enhance the stability and separation performance of the membrane, we implemented a mixed-linker strategy, whereby the ratio of two different types of ligands was adjusted to alter the channel characteristics of the material. We employed 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, and elemental analysis (EA) techniques to determine the mixed-linker ratios of CAU-10-PDC-H. To gain insight into the structural information, we computed the PLDs for different ratios of mixed-linker CAU-10-PDC-H. In gas separation experiments, we found that CAU-10-PDC-H with a mixed-linker ratio of 7:3 exhibited high CO2 permeability (over 1,000 Barrer) and superior separation factors for CO2/N2 and CO2/CH4 separations (both over 50) compared to the majority of previously reported MOF membranes. Long-term gas separation tests, in situ XRD, and in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy also revealed that CAU-10-PDC-H (7:3) had a stable structure and high separation performance. In addition, we successfully fabricated a two-dimensional CAU-10 nanosheet using a surfactant-assisted method and optimized synthesis conditions. We also used the Maxwell equation to predict the performance of mixed-matrix membranes (MMMs) containing CAU-10 nanosheets as fillers within various polymer matrices, which may provide a basis for future studies. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92635 |
DOI: | 10.6342/NTU202400968 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 化學工程學系 |
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