- 學位論文
微波輔助酸化奈米碳管之製備鑑定及其在環境分析之應用
Microwave-assisted preparation and characterization of acidified carbon nanotubes targeted for applications in environmental analysis
摘要
奈米材料具有獨特性質，如奈米尺寸、高比表面積、超順磁等。已被許多不同領域廣泛應用。奈米碳管為其中最熱門材料之一，各領域皆嘗試開發奈米碳管獨特之功能使其應用效能最佳。在製作奈米碳管應用材料中，修飾與官能化奈米碳管表面即為相當重要之步驟，最常見官能化為酸化奈米碳管使得羧酸基存在於奈米碳管表面，得以進行後續之反應。因此酸化後之碳管，其羧酸基之數量與分佈，酸化後之結構變化，皆會影響在分析上之應用結果。本研究即探討影響酸化奈米碳管之參數，對於羧酸基數量、分佈之影響，與在環境分析應用的潛力。 微波輔助方法，被視為符合綠色化學方法之一。以微波輔助酸化方法，酸化不同之奈米碳管，微波系統可穩定控制酸化時間與溫度，與傳統酸化方法相比，除節省反應時間，也可得到酸化程度穩定且舉有再現性之奈米碳管。本研究探討以改變微波輔助酸化反應參數，如溫度、時間，對奈米碳管酸化程度之影響。其中以反向滴定估算羧酸基在碳管表面之數量，拉曼光譜分析與掃描式電子顯微鏡比較酸化碳管前後結構之改變，再以磁性奈米粒子與碳管上之羧酸基結合，以穿透式電子顯微鏡評估羧酸基在奈米碳管上之分佈位置，進而探討微波輔助酸化參數與酸化程度之關係。奈米碳管之酸化程度與後續應用效率息息相關，因此以吸附氣體與溶液中重金屬離子做比較，證實不同應用所需酸化奈米碳管程度也不同。
並列摘要
Nanomaterials have been utilized extensively in different fields based on their excellent optical properties, magnetic properties, and high surface area per unit volume etc. Carbon nanotubes (CNTs) are one of popular nanomaterials and have been applied to many research fields in recent years. Modifying or decorating the surface of CNTs with desired functional groups is an important step for preparing CNTs-based materials. The surface of CNTs acidified with carboxylic acid in advance is indispensable to benefit the followed-up reaction. The structure of CNTs after acidification, i.e., the acidified amounts and sites on the CNTs’ surface was known to affect their analytical applications, such as gas adsorption or heavy metal extraction. This motivated us to further explore the preparation parameters that affect the amounts and sites of carboxylic acid on the CNTs’ surface, which benefits subsequent analytical application. Microwave-assisted acidification, being regarded as green chemistry method, was employed to acidify different kinds of CNTs in this study. Various experimental parameters for microwave acidification (temperature, amounts of acid, and duration of microwave) were tested. Acid-base titration was applied to evaluate the amounts of carboxylic acid modified on to CNTs’ surface. The structure of CNTs after acidification was determined by Raman spectroscopy. Acidified sites were investigated first by acidified CNTs grafted with magnetic nanoparticles (MNPs) of transmission electron microscopy (TEM) analysis. Preliminary results of gas adsorption respective gas and heavy metal extraction would be investigated in the new future by using appropriate CNTs after optimal acidified conditions were confirmed.