- 學位論文
利用摻氮二氧化鈦改質聚偏氟乙烯薄膜
Antifouling plasma-grafted PVDF membrane coated with nitrogen-doped TiO2
摘要
薄膜是個在水處理上經常使用到的一項程序，但其因為會有使用壽命以及薄膜因積垢(fouling)阻塞導致通量下降並了解壓力上升之問題，因此本研究以電漿之方式改質薄膜，並以摻雜(dope)氮二氧化鈦進行塗佈，可增加薄膜表面之親水性進而提高薄膜通量以及減少透膜壓力，其中二氧化鈦的光催化作用(Photocatalytic)以及自淨作用(Self-cleaning)可以降低其積垢。本實驗使用電漿薄膜改質方式以及摻氮二氧化鈦改質方法，並使用兩種模擬污染物來測試經由薄膜光催化後，何種薄膜對於積垢之恢復能力最佳，其後再進行真實污染物測試，以得知是否適用於此真實污染物。 結果顯示，摻氮二氧化鈦改質薄膜於BSA溶液時，潤洗後照射紫外光10分鐘即可使通量恢復97%，而壓力部分也可達到接近於初始壓力，30分鐘後可達到100%之通量恢復率；在Alginate溶液時，發現改質薄膜較難以物理清理之潤洗方式去除表面積垢，但經由光催化，依然可去除相當多於物理潤洗無法去除的積垢；在污水廠進流水作為污染物時，其於紫外光催化階段時雖然相對於潤洗階段可多恢復12.5%，但總恢復效果依然僅有84.38%，距離初始通量尚有一段距離；以自來水廠進流水為污染物時，N-Doped TiO_2/PVDF薄膜之壓力遠低於其他、通量亦高於其他兩者，是因其親水性高之緣故，而於潤洗階段時較難以去除其積垢，紫外光階段時雖有少量上升，但上升幅度相當小，代表自來水廠及污水廠進流水所導致之積垢較難以光催化進行去除，而在可見光部分，薄膜有較低之通量與壓力，但所需的持續照射及操作時間遠高於使用紫外光進行光催化所花時間。
並列摘要
Although membrane bioreactor has high treatment performance to produce good quality of the effluent for reuse and recycle, high cost and fouling are recognized as the most serious problems for this technology. Immobilization of the semiconductor nanoparticles on the modified membrane surface is a promising method to mitigate fouling effects and increase life time of the membrane. In this study, we used plasma treatment to induce peroxide on the surface of a commercial poly(vinylidene fluoride) (PVDF) membrane and coated with nanoparticle N doped TiO2. The morphology and hydrophilicity of N-TiO2/PVDF were characterized by FTIR–ATR, SEM and contact angle. Antifouling properties of N-doped TiO2 self-assembled membrane were also investigated using the solution of BSA, alginate and real domestic wastewater. The results indicate that the membrane’s hydrophilicity was enhanced by adding 1.5 g of the catalyst and the photocatalytic activity of N-doped TiO2 under UV light exposure of 30 min was efficient to remove the strongly bounded foulants on the membrane surface which causes membrane fouling. Membrane flux was completely recovered for BSA and alginate whereas it was about 84% for real wastewater. This demonstrates that immobilization of N-doped TiO2 on membrane was successful to minimize membrane fouling by the increase of hydrophilicity and photocatalytic capability.