本研究之主要目的為探討親水性聚乙烯亞胺(Poly(ethylenimine))改質聚嗍碸(Polysulfone)、聚醚醯亞胺(Polyetherimide)製備出非對稱複合膜並應用於滲透透蒸發乙醇/水溶液分離。研究中利用水作為沉澱劑以濕式相轉換將PSF、PSF/PEI膜成型並利用UV光促進PEI披覆反應並增加膜面之親水性，研究中利用接觸角測量儀探討薄膜親水性改質程度並以滲透蒸發測試探討滲透蒸發分離性能之提升。
研究中探討高分子濃度變化、聚乙烯亞胺濃度變化、離子化、進料濃度及溫度變化對滲透蒸發效能之影響，研究結果發現，隨著高分子濃度增加其薄膜緻密層增厚而降低膨潤所造成選擇性增加，其通透量分別為158 g/m2hr、267 g/m2hr、186 g/m2hr，選擇性分別為255、211、334，而以UV光披覆聚乙烯亞胺改質聚嗍碸、聚醚醯亞胺、聚嗍碸/聚醚醯亞胺，其通透量分別為164g/m2hr、279g/m2hr、186g/m2hr，選擇性為553、511、524，能夠有效提升選擇性，且在接觸角測試結果顯示，聚乙烯亞胺改質顯示親水性增加。以上改質薄膜離子化後可對滲透蒸發分離性能有良好之效果，其通透量分別為187 g/m2hr、229 g/m2hr、200 g/m2hr，選擇性分別為541、545、636。研究結果顯示高溫下其水合能力降低，高分子分子鏈間隙變大，導致薄膜分離係數下降、透過率增加之原因，當乙醇進料濃度增加時水合作用變小，膨潤度減少使物質穿透薄膜時其穿透能力影響變差。藉由聚乙烯亞胺改質非對稱薄膜可有效增進親水性並製備出具有高滲透蒸發分離性能對於乙醇/水溶液分離之複合膜。 The purpose of this investigation is focused on the hydrophilic modification of polysulfone(PSF), poly ether imide(PEI), and polysulfone/ poly ether imide membranes on the improvement of separation performance of pervaporation process for dehydration of ethanol/water mixtures. The wet phase inversion method was used to prepare the modified membranes and posted coating poly ethylene imine for hydrophilic enhancement. The hydrophilic properties of modified membranes were tested by water contact angle measurement.
The influent factors on the separation performance of modified membranes were included casting polymer concentration, poly ethylene imine concentration, ionization, feed ethanol concentration and operation temperature in pervaporation process. It was found that the increase in casting polymer concentration increased the skin layer thickness and improved the separation factors of membrane. The optimum prepared polysulfone membrane presented a 267 g/m2hr permeation flux and 334 separation factor. The best poly ethylene imine coating membrane showed a 200 g/m2hr permeation flux and 636 separation factor on pervaporation test. It is worth to noted that those modified membrane will be further increased the separation factor after using the chloride acid ionization. The permeation flux increased with increasing the operation temperature during the PV test due to the enhancement on polymer chain mobility of in the PV process. On the other hand, the feed ethanol concentration on the membrane swelling properties showed the significantly changed the permeation and separation behavior in the PV process. It is concluded that the modification of polyethylene imine coating and ionization exactly increased the hydrophilic of membranes and also improved the separation performance in this investigation.
