聚氨基甲酸酯改質膜應用於滲透蒸發程序分離乙醇水溶液

Pervaporation Separation of Ethanol-Water Mixture Through Modified Polyurethane Membrane

陳瑩純(Ying-Chun Chen)

指導教授 ： 許克瀛

中原大學/工學院/化學工程研究所/碩士(2003年)

https://doi.org/10.6840/cycu200300510

摘要

聚氨基甲酸酯膜對乙醇水溶液分離選擇性不佳，但是它具有不錯的機械和化學性質。因此以此聚氨基甲酸酯膜為基材，利用化學接枝法，於基材表面分別接枝上親水性單體，甲基丙烯酸羥乙酯和丙烯酸羥丁酯，改善其膜的親水性質，以滲透蒸發分離程序應用於分離乙醇水溶液。探討親水性單體濃度、結構對膜基材接枝度的影響。接枝度、進料濃度、進料溫度、親水性單體種類不同等因素，對膜的選擇比和透過率的影響。
本研究中，單體的濃度與單體的結構皆會影響其接枝度的多寡，單體濃度過高或過少都會造成接枝度下降。接枝度多寡、進料中乙醇含量多寡、進料溫度高低、親水性單體種類等，都會影響此改質膜應用於乙醇水溶液滲透蒸發，選擇比及透過率的高低。
實驗結果顯示，進料乙醇濃度90wt%，進料溫度25℃下，PU-g-HEMA膜，接枝度17.79%，選擇比99.07，透過率6133 g/m2hr ;PU-g-HBA膜，接枝度38.11%，選擇比387.12，透過率6196 g/m2hr，與未改質PU膜，選擇比15.56，透過率4335 g/m2hr，進行比較，呈現出一較佳的分離效果。

關鍵字

透過率 ； 選擇比 ； 滲透蒸發 ； 親水性單體 ； 接枝

並列摘要

Polyurethane (PU) membrane has a poor selectively for separating ethanol-water mixtures, but it has good mechanical properties and chemical resistance. Polyurethane membrane is suitable to be used as matrix. In order to improve the hydrophilic property of the PU membrane, utilize chemical initiation to graft hydrophilic monomers, 2-hydroxyethyl methacrylate (HEMA) and 4-hydroxybutyl acrylate (HBA), onto polyurethane membrane, respectively. The grafted membrane was applied in the pervaporation processes for ethanol-water separation. Changing degree of grafting onto polyurethane membrane with initial monomer concentration added was investigated. The effects of degree of grafting, feed concentration, feed temperature, and different kinds of hydrophilic monomer on the variation of separation factor and permeation rate were investigated.
In this study, the factors of the initial monomer concentration, and monomer structure were affected the degree of grafting on the PU membrane. Higher and lower initial monomer concentration makes lower degree of grafting. The effects of degree of grafting, feed composition, operating temperature, and different kinds of hydrophilic monomer on the separation factor and permeation rate of ethanol-water pervaporation of grafted membranes were studied.
From the experiment results, the separation factors of 99.07 and 387.12 and permeation rates of 6133 and 6196 g/m2hr for the PU-g-HEMA membrane with a degree of grafting, 17.79%, and the PU-g-HBA membrane with a degree of grafting, 38.11%, respectively, under the conditions of 90wt% ethanol feed concentration, and 25℃ operating temperature. Compared with PU membrane, which possess the separation factor of 15.56 and permeation rate of 4335 g/m2hr, the modified PU membranes show appreciable improvement in the performance.

並列關鍵字

graft ； pervaporation ； permeation rate ； hydrophilic monomer ； separation factor

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