添加劑對聚碸中空纖維膜結構型態及複合膜滲透蒸發分離效能之影響

Effect of additive on the morphology of PSf hollow fiber membrane and pervaporation performance of chitosan/PSf composite hollow fiber membrane

莊旭嘉(Syu-Jia Jhuang)

指導教授 ： 賴君義 ； 蔡惠安

中原大學/工學院/化學工程學系/碩士(2009年)

https://doi.org/10.6840/cycu200900017

摘要

ㄧ般利用濕式紡絲法所製備的Polysulfone (PSf)中空纖維膜，薄膜外表面會形成緻密皮層，因此在薄膜分離程序上會具有低透過量。本研究室先前的研究上，於室溫下利用Vapor induced phase separation (VIPS) 可改善PSf中空纖維膜接近外表面結構的連通性。因此在本研究使用VIPS技術並結合造孔劑poly(ethylene glycol) (PEG)，期待能製備出結構連通性較佳的PSf中空纖維膜，並以此薄膜為基材利用dip-coating方式製備chitosan (CS) - γ-glycidoxypropyl- trimethoxysilane (GPTMS)/PSf複合中空纖維膜，應用於滲透蒸發程序分離異丙醇水溶液。
研究結果發現，以26wt% PSf/N-methyl pyrrolidinone(NMP)紡絲液紡製PSf中空纖維膜時，在較低的氣距下(0~20公分)隨著氣距增加外表面孔洞會有合併成長的現象，故平均孔洞大小逐漸增大；在較高氣距下(20~60公分)由於持續的吸附水氣導致鑄膜液黏度提升，不利於孔洞的合併成長，因此平均孔洞大小並不會隨著氣距的提升而持續增大。於鑄膜液中添加PEG會使黏度增加，使孔洞合併成長受到限制而形成較小的孔洞。增加製膜溫度促使空氣中水氣分子運動更劇烈，於短時間下鑄膜液可吸附大量的水氣使相分離速率提升。
本研究中同時發現利用VIPS製膜技術結合造孔劑PEG 200，可製備出結構連通性較佳的PSf中空纖維膜，其純水透過通量為2010±198 g/m2 h。以此薄膜為基材並以2wt% GPTMS為交聯劑之CS 溶液為塗佈液，利用 dip-coating 方式製備的CS-GPTMS/PSf複合中空纖維膜，於25oC下應用於滲透蒸發程序分離90 wt%異丙醇水溶液，其透過量為131±15 g/m2h，透過水濃度為98.7±0.8 wt%。

關鍵字

聚? ； 水氣誘導式相分離 ； 聚乙二醇 ； 幾丁聚醣 ； 複合中空纖維膜 ； 滲透蒸發

並列摘要

Generally, a dense skin layer would be found in the outer surface of wet-spun Polysulfone (PSf) hollow fiber membrane resulted in the low permeation rate during the separation process. In the previously study of our lab, it can be found that the pore connection of the PSf hollow fiber membranes outer layer could be improved by using Vapor Induced Phase Separation (VIPS). In this study, PSf hollow fiber membranes were fabricated by combining VIPS process with Poly(ethylene glycol) (PEG) additive to form a well pore connection PSf hollow fiber membrane. Moreover, PSf hollow fiber membrane was also used as the substrate to fabricate the Chitosan(CS)/PSf composite hollow fiber membrane via dip-coating CS/γ-glycidoxypropyl-trimethoxysilane (GPTMS) solution onto the outer surface of PSf hollow fiber membrane for pervaporation of aqueous isopropanol (IPA) solution.
The results show that by using PSf(26wt%)/NMP as the dope, the average pore size of the outer surface of PSf hollow fiber membrane increased with increasing air gap, resulted from the coarsening effect for shorter air gap system (0~20cm). While for longer air gap system (20~60cm), the surface average pore size was kept constant whatever the air gap were increased. By increasing the formation temperature, water vapor was more easy to absorb onto the surface of membrane, structure evolution rate was enhanced resulted from the increase of phase separation.
Furthermore, a well pore connection PSf hollow fiber membrane with 2010±198 g/m2h of pure water flux was also obtained by combining VIPS process with PEG 200 in this study. The CS-GPTMS/PSf composite hollow fiber membrane was prepared by dip-coating 2 wt% GPTMS added CS solution onto the PSf hollow fiber membrane. The permeation rate and water content in permeate for 90 wt% aqueous IPA solution at 25oC through CS/PSf composite hollow fiber membrane were 131±15 g/m2h and 98.7±0.8 wt%, respectively.

並列關鍵字

poly(ethylene glycol) ； vapor induced phase separation ； polysulfone ； chitosan ； composite hollow fiber membrane ； pervaporation

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