鈣沸石咪唑骨架孔洞粉體用於中高溫CO2捕獲技術

Abstract

本研究中，主要以合成適用於高溫環境(700oC)下之高捕獲效能及兼具效能再活化之奈米孔洞粉體製備技術為核心研究。進一步針對不同適用溫度範圍區間之固態捕獲劑逐一比較與評估其二氧化碳捕獲及效能活化效益。首先利用添加Ca金屬元素藉由離子交換法將其元素置入沸石咪唑骨架，以設計適用於中高溫二氧化碳捕獲之鈣金屬沸石咪唑骨架孔洞粉體(calcium zeolitic imidazolate framework, Ca-ZIF)。此部份的研究將利用調控金屬溶液濃度之比例，探討其製程優化，接著以XRD和FTIR驗證其粉體特徵結構及鍵結，利用氮氣等溫吸脫附測量其比表面積、孔體積及孔洞大小，再以SEM觀察表面形貌與微結構鑑定，最後搭配高溫處理將其粉體奈米孔洞化。二氧化碳捕捉測試將以TGA及Fixed-bed進一步探討Ca-ZIF奈米孔洞粉體之CO2捕捉與抗劣化效果的分析。第二部分將取經過長效捕獲迴圈後之劣化粉體，利用溶解-再結晶之水合作用法進行Ca-ZIF奈米孔洞粉體之再活化性能研究，以不同反應時間對應其粉體之成核與結晶速率進行建立活化程序之最佳化，更進一步評估其固態捕獲劑經活化結構重組後之長效CO2捕獲效能與其結構晶體成長特性，進而將此技術發展至最適化於高溫環境(700oC)。

In this study, we proposed to use the impregnation of two metal ions in the node of structure of zeolitic imidazolate framework (ZIF) to synthesize a mixed metal ZIF-Ca/Mg oxide for CO2 capture at high-temperature environment (700oC), respectively. In the first part, we tried to synthesize high specific surface area porous nanoparticles to investigate the CO2 capture capacity and structure stability through the ion exchange method by introducing the Ca ion into the zeolite framework. Subsequently, we characterized the ZIF-Ca/Mg structures by XRD and FTIR. SEM wa used to observe the surface morphology and microstructure. The surface area was further determined by N2 adsorption-desorption isotherms. The re-generable ZIF-Ca/Mg sorbent for CO2 capture was applied to fixed bed technology at medium-high temperature. In the second part, we will investigate the dissolution-recrystallization mechanism of the decay ZIF-Ca/Mg sorbent during regeneration process. The regeneration process will be also discussed. Different reaction times and the nucleation-crystallization rate of ZIF-Ca/Mg sorbent were established to optimize the activation procedure and development of this technology for high-temperature environments (700oC).