使用免乾燥混合法結合沸石咪唑酯骨架-8奈米粒子與Pebax® MH 2030 之高效有機無機複合薄膜在二氧化碳/氮氣分離上的應用

Abstract

自19世紀工業革命以來，大氣中CO2濃度持續上升，造成顯著的全球氣候變遷。因此從大氣中捕捉CO2是目前非常重要的課題。在此研究中，我們使用薄膜分離的方式來分離空氣中的CO2，並利用免乾燥法混合高分子Pebax和金屬有機框架(MOFs) ZIF-8，形成混合基質薄膜(ZIF-8/Pebax® MH 2030 MMMs)，設法提升高分子薄膜的氣體分離效能。 在此研究中，我們利用FE-SEM和EDX觀察到免乾燥混合法可以有效地提升ZIF-8在高分子中的分散性，有效避免ZIF-8的聚集。此外，透過DSC分析，我們利用Tg變化觀察到ZIF-8和Pebax之間的親和性會使部分的高分子產生鏈剛硬化(Polymer chain rigidification)的現象。 我們對ZIF-8/Pebax® MH 2030 MMMs進行氣體分離效能的測試。實驗結果顯示，在單一氣體的環境中，當ZIF-8的添加量為5 wt%時，氣體通透率從115 barrer提升至140 barrer，同時CO2/N2選擇率從26提升至35。除此之外，我們還模擬了大氣環境來捕捉CO2。在ZIF-8的添加量同樣為5 wt%時，氣體通透率從460 barrer提升至500 barrer ，CO2/N2選擇率從19提升至69。相較於未添加ZIF-8的Pebax，選擇率增加了263%。此研究不僅發現利用免乾燥法可以有效的改善ZIF-8在Pebax中的分散性，更重要的是，參雜適當比例的ZIF-8可以有效的提升Pebax薄膜在大氣環境下的氣體分離效能。

Significant global climate change has resulted from the continuous increase in atmospheric CO2 concentration since the Industrial Revolution in the 19th century. Therefore, capturing CO2 from the atmosphere is currently a crucial issue. In this study, we used the mixed matrix membranes (MMMs) for CO2/N2 separation. We incorporated the metal-organic frameworks (MOFs) ZIF-8 into Pebax® MH 2030 to form the mixed matrix membrane (ZIF-8/Pebax® MH 2030 MMMs) by the drying-free method. In this research, we use FE-SEM and EDX analysis to observe that the drying-free method can effectively improve the dispersion of ZIF-8 in the polymer, effectively avoiding ZIF-8 aggregation. Additionally, based on DSC analysis, we found that the polymer chain rigidification phenomenon will increase glass transition temperature (Tg), which is due to the affinity between ZIF-8 and Pebax® MH 2030. We measured the gas separation performance of the ZIF-8/Pebax® MH 2030 MMMs. In a single gas environment case, the 5 wt% loading ZIF-8 MMMs can get higher permeability (140 barrer) than the pure Pebax® MH 2030 (115 barrer), as well as the CO2/N2 selectivity (increased from 26 to 35). Furthermore, we simulated CO2 capture in the atmospheric environment to test the gas separation performance. Adding 5 wt% ZIF-8 into Pebax® MH 2030 can increase gas permeability from 460 barrer to 500 barrer, and the CO2/N2 selectivity increased from 19 to 69 (263% increased). This study shows that the drying-free method effectively improves the dispersion of ZIF-8 in Pebax® MH 2030 . More importantly, the incorporation of an appropriate proportion of ZIF-8 significantly enhances the direct air capture (DAC) performance of Pebax® MH 2030 membranes in an atmospheric environment.