- 學位論文
聚乙烯亞胺(PEI)修飾之官能化磁性奈米吸附劑的製備與應用於環境分析
Preparation of Magnetic Nano-adsorbent Functionalized with Polyethyleneimine and Application for Environmental Analysis
摘要
本研究製備表面修飾有聚乙烯亞胺(PEI)超順磁性奈米吸附劑，利用其奈米級尺寸所表現的大表面積及PEI所具有的化學特性，可以應用於空氣中有機酸及水溶液中的無機陰/陽離子的吸附劑。 製備方法為首先以化學共沉澱法合成磁性奈米粒子，透過PEI分子做表面官能化修飾，以特性分析確認其表面成功的修飾上PEI分子，BET表面積證實其具有大表面積，屬中等吸附力的吸附劑，且具備超順磁的特性，可提供後續應用為吸附劑時有利的條件。 於空氣中有機酸的應用，本研究所製備的磁性奈米吸附劑對於有機酸比商業化吸附劑Tenax TA具較佳的吸附及脫附能力。相較於苯環類的化合物，對於有機酸也有較好的選擇性。於水溶液中的無機陰/陽離子的應用，可以同時吸附無機陰離子和陽離子，且在pH 6調態下有最佳的吸附能力，分別沖提無機陰/陽離子時也具有不錯的回收率。本研究所製備的磁性奈米吸附劑可為具有雙重應用價值的吸附劑，結合奈米科技與環境分析，將有助於改善汙染物的分析方法。
並列摘要
This research prepared magnetic nanoparticles (MNPs) surface modified with polyethyleneimine (PEI), demonstrated their use as adsorbent in gas and liquid phase. MNPs possess the characteristics of high surface area per volume and easy handling by external magnetic field. These novel properties are of great interest for researches from a wide range of disciplines. Both polar groups (amine) and apolar groups (ethylene) are present on the macromolecular chains of PEI, which enable MNPGAPEI to adsorb compounds like organic acids. PEI is a water-soluble polymeric amine and with many nitrogen atoms on the chains, which can produce very strong chelating action for inorganic cations. Besides, PEI is a cationic polyelectrtolyte in aqueous solutions, so there is a strong electrostatic interaction with negatively charged species like inorganic anions. The dual features of PEI permit MNPGAPEI as a universal adsorbent for both inorganic cations and anions. MNPGAPEI were demonstrated as adsorbents for carboxylic acids (analytes are acetic acid, propionic acid, butanoic acid, valeric acid and iso-valeric acid), inorganic cation (Pb), and anion (As). FT-IR and zeta potential analysis were used to verify the surface functional group. Results demonstrated that organic acids were effectively adsorbed onto 50-mg of MNPGAPEI packed in a glass sorbent tube. MNPGAPEI show better adsorption and desorption ability for organic acids than Tenax TA. Optimal desorption temperature and time was 225 ℃ and 6 min, respectively. MNPGAPEI show better selectivity toward organic acid than benzene-like compounds. In aqueous solution, MNPGAPEI possess dual affinity toward both caions (Pb) and anions (As) at pH 6. Desorption study of inorganic cation or anion shows good recoveries. It is expected that the MNPGAPEI could be used as a novel and functional solid adsorbent material for trapping carboxylic acids from atmosphere and inorganic cations and anions from aqueous sample.