新型聚醯亞胺薄膜應用在滲透蒸發程序分離醇類水溶液

Pervaporation separation of aqueous alcohol solution through novel polyimide（PI）membranes

蔡易書(Yi-Shu Tsai)

指導教授 ： 賴君義

中原大學/工學院/化學工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200345

摘要

為了改善聚醯亞胺薄膜在滲透蒸發程序分離時低透過量的缺點，因此本研究利用在聚醯亞胺薄膜的主鏈結構中導入巨形鏈節，提升薄膜之自由體積分率（FFV），藉以增加薄膜在滲透蒸發程序時之透過量。
研究中發現，薄膜FFV之增加的確提升透過量，但整體透過行為趨勢受進料分子與薄膜之間的作用所影響，而不能單以FFV作解釋。其中以BPDA-PI的分離效果最佳，透過量為270.5g/m2h，PSI值為6156。以BPDA-PI膜作進一步探討，發現在乙醇濃度50wt%以下乙醇分子與薄膜之間的塑化效應會隨進料濃度增加而增加，但在50wt%以上高濃度乙醇環境下因為進料分子間的偶化效應增強，而改變透過行為，所以滲透比隨濃度增加而下降。此外針對90wt%醇類水溶液對BPDA-PI膜之滲透蒸發分離效果作探討，發現隨醇類碳數增加透過量減少而選擇比上升，主要是因為醇類本身立體障礙之緣故；另外其透過BPDA-PI膜之活化能隨進料中醇類碳數增加而減小，表示BPDA-PI應用在滲透蒸發分離程序上分離高碳醇水溶液時，膜材對溫度變化的敏感度較低。

關鍵字

自由體積分率 ； 乙醇 ； 滲透蒸發 ； 薄膜 ； 聚醯亞胺

並列摘要

The effect of dianhydride structures on pervaporation performance of alcohol/water mixtures was studied via four types of aromatic polyimide prepared by the two-step polycondensation of diamine, 3,3-Bis[4-（4-aminophenoxy）phenyl] phthalide (BAPP), with different dianhydride, such as : 4,4’-sulfonyldiphthalic anhydride (SDPA), 3,3’,4,4’-biphenyltetra-carboxylic dianhydride (BPDA), 4,4’-oxydi- phthalic anhydride (ODPA), and 4,4’-Hexafluoroisopropylidenediphthalic anhydride (6FDA). The permeation rate was improved by introducing bulky segment into polyimide backbone to increase the fractional free volume of the BAPP-based polyimide membranes. All of membranes exhibited water permselectivity during all process runs. In addition, the effect of plasticizing effect and coupling effect between the feed solution and BAPP-based membrane on the pervaporation performances was also investigated. Furthermore, the effect of feed solution concentration, feed solution temperature and carbon number of feed alcohols on the pervaporation performance were also investigated systematically. The separation factor of 22 and permeation rate of 270.5 g/m2h on the BPDA-PI was higher than other polyimide membranes in this research for 90wt% feed aqueous ethanol solution at 25℃.

並列關鍵字

pervaporation ； ethanol ； membrane ； FFV ； polyimide

參考文獻

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