超疏水聚偏二氟乙烯薄膜於無外加驅動力之油水分離研究

Superhydrophobic PVDF membranes for breaking of water-in-oil emulsions without any driving force

周芳志(Fang-Chih Chou)

指導教授 ： 費安東 ； 張雍

中原大學/工學院/化學工程研究所/碩士(2015年)

https://doi.org/10.6840/cycu201500623

摘要

本研究中，使用了三種不同的製膜方法來設計超疏水聚偏二氟乙烯(PVDF)薄膜，其採用之方法包含蒸氣誘導相分離法(VIPS)、濕式誘導相分離法(LIPS)、以及CF4電漿表面改質法。研究目標期製作出超疏水/超親油薄膜，在不需提供任何透過壓力情況下可以迅速簡單的分離油中水乳液(water-in-oil emulsions)，並且系統性的鑑定薄膜的結構(SEM )及特性，包含孔洞大小、孔隙度、機械強度與疏水性/親油性，以建立設計高分離效能的設計原則。
實驗結果顯示，VIPS薄膜的孔隙度與LIPS薄膜的孔隙度比較，並無太大的差別，但是VIPS薄膜的平均孔洞大小較LIPS薄膜大。而在機械性能方面，LIPS薄膜有比VIPS薄膜更好的拉伸強度及延展性。將LIPS薄膜進行電漿處理，只需2分鐘的CF4電漿改質，即可使LIPS薄膜具有超疏水性質，改質後薄膜的孔隙度雖有下降，但其表面平均孔洞分布並無明顯改變。而機械強度則有明顯的弱化，低於VIPS所製備的薄膜。
本實驗，以甲苯、己烷和二氯甲烷進行油中水乳液製備與過濾研究。VIPS薄膜具高通量(2500 kg/m2h)但低分離效率(97.7%)。而LIPS薄膜之通量只有1000 kg/m2h。LIPS薄膜經過CF4電漿改質所提升的疏水性，可以使分離效能從97.7%提升到98.2%，其分離效能可以達到99.5%以上，在薄膜油水分離應用方面，具有潛力進行高分離效率的破乳化程序。

關鍵字

超疏水PVDF薄膜 ； 非溶劑誘導相分離法 ； 電漿處理 ； 乳液分離

並列摘要

In this study, we prepared superhydrophobic PVDF membranes by three methods. We used the vapor-induced phase separation (VIPS), the liquid-induced phase separation (LIPS) and we applied a plasma surface modification treatment to membranes prepared by LIPS. The secondary treatment aimed at creating supplementary C-F bonds and further increasing the roughness of the surface. In all cases, the goal was to create superhydrophobic/superoleophilic membranes that could readily separate water-in-oil emulsions by a simple process that did not require any transmembrane pressure. Before investigating the efficiency of the water/oil separation, the structure (SEM) and arising properties (pore size, porosity, mechanical properties, hydrophobicity/oleophilicity) of membranes were fully characterized.
The porosity of VIPS and LIPS membranes are similar but VIPS membranes have bigger mean pore size than LIPS membranes. The mechanical properties of LIPS membranes were also stronger than those of VIPS membranes. CF4 plasma enabled to obtain superhydrophobic surfaces within 2 minutes. After that, the porosity slightly decreased and the mean pore size did not show any obvious change. Then, the mechanical properties of modified LIPS membranes were weaker than those of VIPS membranes.
Toluene, hexane or dichloromethane were used to prepare water-in-oil emulsions. The flux of VIPS membranes was the highest among all the membranes (2500kg/m2h). But VIPS membranes also presented the lowest separation efficiency (97.7%). The flux obtained with LIPS membranes was 1000kg/m2h and the plasma modified membranes exhibited similar flux. Results showed that the increase of the hydrophobicity could increase the separation efficiency from 97.7% to 98.2%. For water-in-hexane emulsions, it even reached 99.5%.
Although VIPS membranes have the highest flux, the higher separation efficiency makes the plasma modified membranes better to break the emulsions.

並列關鍵字

Superhydrophobic PVDF membrane ； NIPS process ； plasma treatment ； emulsion separation

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