- 學位論文
製備ZIF-7晶體與ZIF-7/幾丁聚醣複合膜應用於乙醇/水之滲透蒸發分離
Preparation of ZIF-7 crystals and their composite ZIF-7/CS Membranes for Pervaporation Separation of Water/Ethanol Mixtures
摘要
本研究利用水熱法製備出不同形貌大小的ZIF-7（zeolitic imidazolate framework-7）粒子，其ZIF-7粒子形貌有板狀、球狀和奈米顆粒，並探討水熱條件對ZIF-7粒子成長之機制；並把不同形貌的ZIF-7粒子添加於CS(Chitosan)之中，ZIF-7粒子本身與CS展現出相當良好的相容性，並形成無機-有機複合薄膜（mixed matrix membranes, MMMs），而添加ZIF-7的CS薄膜，其滲透蒸發效能均比原本的純CS薄膜展現出更好的通量和選擇比。在90wt%的乙醇水溶液的滲透蒸發分離中，添加0.5wt%的奈米ZIF-7顆粒擁有較高的通量和選擇比；而ZIF-7本身為疏水性粒子，其粒子添加量過多時，會造成粒子間的團聚現象，導致選擇比與通量下降。在滲透蒸發效能方面，以添加0.25克的交聯劑、0.5wt%奈米粒子，擁有最佳的通量742( g/m2h)、選擇比1582和PSI值（pervaporation separation index）1174( Kg/m2h)。 綜合上述之結果，本研究在操作溫度25℃、進料濃度為90wt%乙醇水溶液下進行滲透蒸發分離，其ZIF-7粒子的添加有助於提升高分子薄膜之效能，添加適量交聯劑能助於固化高分子鏈段，藉此提升薄膜之選擇性，且ZIF-7粒子與高分子不會產生排斥，因此能形成較好的複合式薄膜，與過去文獻之滲透蒸發效能相比，其通量與選擇比都優越許多，代表ZIFs這類型的孔洞材料在滲透蒸發應用中極具非常優越的潛力，具備了與材料混合的相容性並提高薄膜之選擇性，這些特性利於無機-有機複合薄膜之製備和應用。
關鍵字
滲透蒸發；薄膜分離並列摘要
In this study, different morphology of the ZIF-7（zeolitic imidazolate framework-7） materials were prepared by hydrothermal method, such as plate, sphere and nano-particles. Then, discuss to the growing of ZIF-7 seeds were effected by hydrothermal conditions.The as-synthesised ZIF-7 materials were successfully incorporated into the chitosan(CS) solution to form the mixed matrix membranes ( MMMs）. The as-prepared MMMs were used to separate mixtures of water/ethanol at 25oC in the pervaporation process. The separation efficiency of MMMs with ZIF-7 materials showed good the flux and separation factor higher than that of pure CS membranes. However, doping too much ZIF-7 hydrophobic particles into the CS solution caused to ZIF-7 materials become agglomeration in the membranes.As a result, the flux and separation factor were decreased. In pervaporation performance, the MMMs with 0.5 wt% ZIF-7 nano-particles doping into the CS solution had higher flux (742g/m2h), separation factor (1582) and pervaporation separation index(PSI, 1174 Kg/m2h). At the same operational conditions, such as 90 wt% ethanol solution and at 25oC operational environment, the separation factor and the flux of the as-prepared membranes clearly exceed the upper limit of the previously reported CS based membranes and MMMs. The present work demonstrates better pervaporation performance of the ZIF-7 particles incorporated CS membrane for the separation of water and ethanol and the feasibility of using this system for pervaporation.