醋酸纖維酯複合膜材之支撐層結構設計與滲透蒸發效能研究

Study on the sub-layer design and pervaporation performance of cellulose-based composite membrane

邱昭諭(Jau-Yu Chiou)

指導教授 ： 李魁然 ； 賴君義

中原大學/工學院/化學工程學系/碩士(2007年)

https://doi.org/10.6840/cycu200700455

摘要

本研究成功製備出應用於滲透蒸發分離程序的幾丁聚醣/醋酸纖維酯/不織布複合薄膜。文中探討高分子濃度於基材薄膜結構影響，經由黏度計的量測，了解鑄膜液之性質，藉由與非溶劑接觸時，薄膜光穿透度值的改變，判斷薄膜成膜速率快慢，以及掃描式電子顯微鏡觀察薄膜結構型態。並且利用滲透蒸發程序對基材薄膜與複合薄膜之分離效能進行探討。所製備的複合膜材對異丙醇水溶液系統，擁有優越的滲透蒸發分離效能；當複合膜材係以1.5 wt% 幾丁聚醣溶液塗佈於9 wt%醋酸纖維酯基材薄膜，而進料為70 wt%異丙醇的水溶液，操作溫度為70℃時，其透過通量為8300 g/m2h，透過水含量可達99 wt%以上。
藉由弱非溶劑---乙醇為凝聚劑，將可製備表面多孔且整體連通之基材薄膜，但礙於薄膜固化速率過於緩慢，不利於實際應用，而利用雙凝聚槽法則可達快速製備表面多孔且整體連通之基材薄膜。經由3wt% 幾丁聚醣溶液塗佈於此多孔基材薄膜上，進行進料為70 wt%異丙醇的水溶液，操作溫度為70℃滲透蒸發操作時，透過通量為7570 g/m2h，透過水含量達99 wt%以上。

關鍵字

結構設計 ； 滲透蒸發 ； 複合膜材 ； 醋酸纖維酯

並列摘要

Membranes with high separation performance are fascinated for lots researchers in the field of pervaporation. In this study, Chitosan（CS）/Cellulose Acetate（CA）composite membrane was fabricated to investigate the effect of CA substrate structure on dehydration performance of aqueous isopropanol（IPA） mixtures. The CA substrate membranes were prepared by various concentration of CA polymer solution. The Scanning electron microscopy （SEM） observation, light transmittance experiment and rheometer measurement results showed that a membrane with denser sublayer and thicker top layer can be formed for higher polymer concentration. The optimum pervaporation performances for 70wt% IPA/H2O mixtures through 9wt% CA polymer solution cast CS/CA composite membrane are 8,300 g/m2h and 99 wt% for permeation rate and water content in permeate, respectively.
By immersing cellulose acetate casting film in ethanol coagulant bath, we could prepare membranes with lacy structure. However, the delay solidification rate, which made the useless in continuous membranes preparation for this system. In the dual-coagulant baths system, we could also prepare membranes with lacy structure and fast solidification, which using alcohol and water were used as the 1st and 2nd coagulant, respectively. The chitosan/cellulose acetate/ non-woven composite membrane made by coating 3wt% chitosan solution on the substrate with lacy structure, had nice pervaporation performances for 70wt% IPA/H2O mixtures at 70℃. The flux and water concentration in permeate are 7570 g/m2h and 99 wt%, respectively.

並列關鍵字

structure design ； Cellulose acetate ； Pervaporation ； Composite membrane

參考文獻

1. M. H. V. Mulder, “Basic principles of membrane technology”, Kluwer Academic Publishers, The Netherlands, (1997).

3. S. P. Nunes, K. V. Peinemann, “Membrane technology in the chemical industry”, Wiley, Germany, (2003).

4. U. S. Toti, T. M. Aminabhavi, “Different viscosity grade sodium alginate and modified sodium alginate membranes in pervaporation separation of water + acetic acid and water + isopropanol mixtures”, J. Membrane Sci., 228 (2004) 199-208.

5. M. Y. Teng, K. R. Lee, S. C. Fan, T. T. Wu, J. Y. Lai, “Development of aromatic polyamide membrane for pervaporation and vapor permeation”, J. Membr. Sci., 164 (2000) 241-249.

6. H. A. Tsai, S. C. Chen, W. L. Chou, K. R. Lee, M. C. Yang, J. Y. Lai,” Pervaporation of water/alcohol mixtures through chitosan/cellulose acetate composite hollow fiber membranes” J. Appl. Polym. Sci., 94 (2004) 1562-1568.