磁場應用於薄膜積垢防止之研究

Application of Magnetic Field for Preventing Membrane Fouling

李振民(Jeng-Ming Li)

指導教授 ： 林正芳

國立臺灣大學/工學院/環境工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.01125

摘要

本研究嘗試不同磁場強度與磁處理方法搭配薄膜處理程序，觀察磁處理對薄膜積垢與滲流率的影響，透過不同薄膜孔徑(100 kD與10 kD)去探討其效率。並觀察腐植酸與純水在磁場中的特性變化與FEG-SEM與AFM觀察薄膜膜面的狀況。
磁場強度由150 G~10000 G，滲流率隨著磁場強度的增強而衰減的越緩慢，最多衰減至原始的39 %(10000 G)；停留處理依磁場強度越大而可增加滲流率5 %~18 %。經過特性分析後推測腐植酸顆粒在磁場中負電荷減少而互相吸引破壞了整個系統的穩定性而形成較大的顆粒，藉由掃流方式對積垢層造成一定程度的破壞而造成瞬間滲流率上升的現象，而溶氧的上升與TOC的下降等特性皆可解釋對薄膜積垢造成一定的破壞。另一方面水分子經磁化後磁化處理會破壞水原來的結構，使較大水分子集團變成較小的水分子集團，分子變小容易穿入積垢內造成滲流量的上升也是其因素之一。另外水分子經過磁場變小易通過積垢層，但在初期積垢層未完整，所以滲流率並無明顯提升，在後期積垢層逐漸形成後水分子穿透積垢層而達到滲流率減緩的結果則易顯現出來，TOC去除率也因為水分子經磁化後滲透性強，水分子易穿透積垢中而造成TOC去除率的上升。
FEG-SEM與AFM觀察可看出經磁處理下薄膜積垢因水分子易進入積垢中造成積垢結合力受影響部分脫落所以有分佈不均與粗糙度上升的現象

關鍵字

磁應用 ； 磁化水 ； 超過濾薄膜

並列摘要

The research uses different magnetization and magnetic treatment to work with membrane treatment process. Objectives of this research are to observe the effect of magnetic treatment to membrane fouling and the rate of permeate. Other objective is to determine effectiveness of the use of magnetic treatment by using different MWCO (100 kD and 10 kD). The investigation was also aimed to see the molecular weight distribution alteration of humic acid and pure water in magnetic field, and how they seem in FEG-SEM and AFM of the membrane surface.
The magnetization is from 150 G~10000 G. The rate of permeate decay slower according to the intensity of magnetization, and maximum is the 39 % of beginning (10000 G). Stop treatment could increase the rate of permeate about 5 %~18 % by increasing the intensity of magnetization. After characterization analysis, we presume that the decreasing of humic acid particle in negative charge of magnetic field attracts humic acid particles to each other and damage the stability of whole system to become a larger particle.
Cross-flow filtration was used to make certain damage on fouling layer, and to found out the phenomenon of increasing of momentary permeate. The increasing of DO and the decreasing of TOC could both be explained to be cause of certain damage which cause membrane fouling. Other case, water molecule, the original structure of water was destroyed after the process of the magnetic treatment. It makes large water cluster become smaller one. Small molecule would then easy to pass through membrane fouling and makes the increasing of the rate of permeate.
Moreover, water molecule after the magnetic treatment become small which cause the water to be easy to pass through the fouling layer.
In the beginning, the fouling layer has not completed and the rate of permeate didn’t have obvious increasing. Afterward, the fouling layer started to form and water molecule pass through the membrane to make the rate of permeate lower. The result was much obvious. The rejection rate of TOC also had better permeability, because of the water molecule after the magnetic treatment. Water molecule passes fouling layer easily and ensued the increasing of rejection rate of TOC.
By using FEG-SEM and AFM, we could tell that the membrane fouling after the magnetic treatment will partially fall, because the water molecule passed through the fouling layer easily and made effect to the fouling bond. So, it would have distribution unequal and roughness to be increased.

並列關鍵字

magnetic application ； magnetic water ； Ultrafiltration

參考文獻

方隆成 (2006) 以酵素清洗超濾薄膜過濾腐植酸之不可逆積垢與分析 國立台灣大學環境工程學研究所碩士論文

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