中空纖維滲透蒸發膜於醇類水溶液脫水之研究

Study on dehydration of aqueous alcohol mixtures for hollow fiber pervaporation membrane

王騰毅(Teng-Yi Wang)

指導教授 ： ARRAY(0xa7fefec)

中原大學/工學院/化學工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000562

摘要

本研究中經由界面聚合法選用水相單體為1,6 hexanediamine (HDA), ethylenediamine (EDA), diethylenetriamine (DETA), tetraethylenepentamine (TEPA) ，油相單體則為trimesoyl chloride (TMC)來製備一系列PA/ PAN中空纖維複合薄膜，主要探討水相單體之胺官能基數目對於其PA/ PAN中空纖維複合膜滲透蒸發效能與結構型態之影響。實驗結果顯示，當水相單體胺官能基數目越多時，所製備之中空纖維複合膜展現較優異的滲透蒸發效能。由XPS鑑定結果得知，胺官能基數目越多時，其中空纖維複合薄膜之聚合層有較多的聚醯胺官能基，表示其交聯程度較高。經由光穿透實驗則發現當胺官能基數目越多時，free standing薄膜之界面聚合反應速率較快。在正子消散儀量測結果，則發現當胺官能基數目越多時，其S參數值較低，表示聚合層之自由體積較小，也可以說明其有較高的交聯程度。
經由AFM, SEM, XPS, 對水接觸角量測儀以及光穿透度實驗之實驗結果，可以得知當水相單體胺官能基數目越多時，界面聚合反應速率較快，且聚合層表面之聚醯胺含量有較多的趨勢，因此則變得較為親水。最後經由正子消散儀之結果，發現胺官能基數目越多時，自由體積數目較小，表示其交聯程度較高。以上之結果與滲透蒸發效能實驗之結果能相互應證。
在上個部份得知當胺官能基數目越多時，中空纖維複合薄膜展現較好的滲透蒸發效能，其理想界面聚合反應條件為氫氧化鈉水解時間30分鐘，水相單體為2wt% TEPA，浸泡時間為1分鐘；油相單體為1wt% TMC，反應時間為30秒。於25℃滲透蒸發效能實驗分離90wt%乙醇水溶液其透過效能為透過量342g/m2h，透過端水濃度為97.5wt%。因此在第二部份中，添加二氧化矽於PAN中空纖維膜中，期望藉由二氧化矽來提昇薄膜之親水性與進一步來提昇中空纖維複合薄膜之滲透蒸發分離效能。儀器部份使用SEM與AFM觀察表面結構型態，並使用SEM-EDX觀察二氧化矽之分佈狀況。發現二氧化矽之分散情況良好，但是於二氧化矽添加含量過高時會有抑制巨型孔洞的現象。藉由表面接觸角量測儀量測二氧化矽/PAN平板膜之表面親疏水性，發現膜表面之親水性會隨著二氧化矽添加量之增加而有上升的趨勢。進行純水透過實驗來量測基材之透過阻力，發現純水透過量隨著二氧化矽添加量之增加有先上升後下降之趨勢，在二氧化矽添加量為5wt%時有最高的純水透過量。最後進行界面聚合反應並應用於滲透蒸發效能實驗，結果僅在透過端水濃度有些微上升。因此在界面聚合程序中不進行水解程序，發現能明顯提高其透過量，且由SEM觀察發現聚合層與基材之貼合性良好，滲透蒸發效能實驗於25℃下分離90wt%乙醇水溶液其透過效能為透過量479g/m2h，透過端水濃度為99.1wt%。

關鍵字

水相單體 ； 界面聚合 ； 中空纖維膜 ； 複合薄膜 ； 二氧化矽

並列摘要

In this study, a series of PA/ PAN composite hollow fiber membranes (HFMs) was prepared by the interfacial polymerization of various water-soluble amine monomers 1,6 hexanediamine (HDA), ethylenediamine (EDA), diethylenetriamine (DETA), and tetraethylenepentamine (TEPA) and oil-soluble monomer trimesoyl chloride (TMC) to investigate the effects of functional groups and structural patterns of the monomers on the pervaporation performance of the PA/PAN composite hollow fiber membranes for separating aqueous alcohol solutions. When water-soluble monomer had more amine functional groups, the PA/ PAN composite hollow fiber membrane exhibited superior pervaporaion performance. As identified by XPS, results indicated that the more the amine functional groups, the higher degree of cross-linking in the polymerized composite hollow fiber membrane . From light transmission experiments, it was found that the more the amine functional groups, the faster the free-standing membrane interfacial polymerization reaction rate. As a result of the positron measurements, it was found that the more the amine functional groups, the lower the S parameter values and the smaller the polymer free volume, which can also explain the higher degree of cross-linking. From the results obtained by means of AFM, SEM, XPS, water contact angle measurement, and light transmission, we found that the more the water-soluble monomer amine functional groups, the faster the interfacial polymerization reaction rate and the higher the degree of cross-linking on the polyamide surface, resulted from more hydrophilic. Furthermore, from positron results, it was found that the more the amine functional groups, the smaller the free volume amount. The above results and the pervaporation performance experimental results were correspond with each other.
The ideal interfacial polymerization conditions for PAN hydrolysis time with NaOH, TEPA concentration, TEPA soaking time, TMC concentration and reaction time were 30min, 2wt%, 1min, 1wt% and 30sec, respectively. In a pervaporation performance test at 25 C for separating 90 wt% ethanol, the permeation flux was 342 g/m2h and the concentration of water in the permeate was 97.5 wt%. To further improve the pervaporation performance of PA/mPAN composite hollow fiber membrane, silica was added in the PAN hollow fiber membrane, and with this addition, it was expected to increase membrane’s hydrophilicity and the pore size of the outer surface. SEM and AFM were the instruments used to observe the morphologies and the roughness of the silica/PAN hollow fiber membrane, and scanning electron microscope energy-dispersive x-ray spectroscopy (SEM-EDX) was used to observe the distribution of silica in hollow fiber membrane. It was found that silica was distributed well on the outer surface of the hollow fiber membrane. With an increase in the content of silica, the roughness decreased. From the water contact angle measurement, it was revealed that with an increase in the silica content, the hydrophilicity of the hollow fiber membrane increased. Pure water permeation test was carried out, and the finding was that as the content of silica increased, the pure water flux increased first and then decreased gradually. The 5 wt% silica added PAN hollow fiber membrane was chosen to prepare the PA/silica-mPAN composite hollow fiber membrane through interfacial polymerization. However, the pervaporation performance results showed that there was no improvement. Therefore, we changed the interfacial polymerization process, we did not carry out the hydrolysis process for PAN hollow fiber membrane. As a result, the PA/silica-PAN composite membrane exhibited better pervaporation performance. The pervaporation separation of 90 wt% aqueous ethanol solution at 25 C using the PA/silica-PAN composite hollow fiber membrane gave a permeation rate and a water concentration in the permeate of 479 g/m2h and 99 wt%, respectively.

並列關鍵字

aqueous monomer ； interfacial polymerization ； hollow fiber membrane ； silica ； composite membrane

參考文獻

[32] 高瑟聰, 基材膜結構對滲透蒸發複合膜效能之影響, 台灣大學高分子科學與工程學研究所博士論文, (2010).

[34] 魏士偉, 聚醯胺/醋酸纖維酯複合膜應用於滲透蒸發分離之研究, 中原大學化學工程學系碩士學位論文, (2009).

[36] 蘇郁蕙, 幾丁聚醣混成膜中無機材成份對滲透蒸發效能之影響, 中原大學化學工程學系碩士論文, (2004).

[37] 謝昀穎, 新型超薄滲透蒸發複合膜之研究, 中原大學化學工程學系碩士學位論文, (2008).

[45] 黃書賢, 界面聚合聚醯胺複合膜應用於滲透蒸發分離程序之研究, 中原大學化學工程學系博士學位論文, (2008).