聚電解質錯合物/氧化石墨烯奈米複合薄膜用於滲透蒸發分離之研究

Fabrication of polyelectrolyte complex/graphene oxide nanocomposite membrane for pervaporation dehydration

楊偉廷(Wei-Ting Yang)

指導教授 ： 洪維松

中原大學/工學院/化學工程研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400718

摘要

中文摘要
本研究利用酸保護與去保護方式將陽離子聚電解質分支狀聚乙烯亞胺(branched polyethylenimine, bPEI)與陰離子聚電解質羧甲基纖維素鈉 (polyelectrolyte sodium carboxymethyl cellulose, CMCNa)進行離子錯合，形成可溶解型之聚電解質錯合物(polyelectrolyte complex, PEC)。成功將氧化石墨烯graphene oxide (GO)均勻分散於bPEI溶液中與CMCNa進行離子錯合，製備成GO-PEC奈米複合物，並將其製備成滲透蒸發複合薄膜。利用全反射式傅立葉轉換紅外線光譜儀、表面接觸角量測儀、場發式電子顯微鏡、原子力顯微鏡與可變單一能量慢速正電子束分析儀等儀器，探討薄膜之化學結構、親水性、物理型態、表面粗糙度以及多層結構之自由體積等性質。
研究中探討添加不同濃度GO以及改變離子錯合度對於薄膜之化學結構、微結構與滲透蒸發效能之影響。實驗結果發現以100 ppm GO且錯合比例為0.7之條件製備的GO-PEC 0.7奈米複合薄膜，於40°C下分離90 wt%甲醇水溶液時展現最佳的分離效能，透過量為636 g/m2h，透過端水濃度可達74 wt%，分離選擇性優於PEC 0.70複合薄膜(透過量662 g/m2h透過水濃度為64 wt%)。接著探討滲透蒸發操作條件，對於滲透蒸發分離效能之影響，其中包含進料溫度、濃度與不同碳數之醇類溶液。相較於PEC複合薄膜而言， GO-PEC奈米複合薄膜可有效抑制薄膜膨潤現象，且GO之層狀結構可增加進料物種透過路徑，因此得到較佳的滲透蒸發分離效能。經由慢速正電子分析儀測量發現，錯合度提高時可增加聚電解質錯合物之間的排列密度。

關鍵字

聚電解質錯合物 ； 氧化石墨烯 ； 滲透蒸發

並列摘要

Abstract
This study used the protection and deprotection methods for acids to induce a complexation reaction of cationic branched polyethylenimine (bPEI) and anionic polyelectrolyte sodium carboxymethyl cellulose (CMCNa) to form a soluble polyelectrolyte complex (PEC). In addition, this study successfully dissolved graphene oxide (GO) in a bPEI solution and induced a complexation reaction of GO and CMCNa to produce GO–PEC nanocomposites, which were in turn used to fabricate pervaporation composite films. An attenuated total reflection Fourier transform infrared spectroscope, contact angle analyzer, field emission electron microscope, atomic force microscope, and variable monoenergy slow positron beam were used to examine the chemical structure, hydrophilicity, physical morphology, and surface roughness of the films and the free volume between the layers of the films.
This study explored the effects of various concentration levels of GO and various degrees of complexation on the chemical structure, microstructure, and pervaporation performance of the film. The experiment results indicated that a GO–PEC 0.7 nanocomposite film fabricated using 100-ppm GO with a complexation ratio of 0.7 optimally separated 90-wt% aqueous methanol solution at 40 °C. The permeation amount was 636 g/m2h, and the water concentration at the permeate side was 74 wt%. The separation selectivity of GO–PEC 0.7 nanocomposites was superior to that of PEC 0.70 composite films (the permeation amount was 662 g/m2h and the water concentration at the permeate side was 64 wt%). Subsequently, this study investigated the effects of pervaporation conditions (including feed temperature, feed concentration, and alcohol solutions with various carbon numbers) on pervaporation separation. Compared with PEC composite films, GO–PEC nanocomposite films effectively inhibited film swelling. In addition, the layered structure of GO provided additional permeation pathways for feed, thereby yielding superior pervaporation separation performance. By using slow positron beam analysis, this study found that enhanced complexation degree increased the density of the arrangement between polyelectrolyte complexes.

並列關鍵字

polyelectrolyte complex ； graphene oxide ； pervaporation

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