Application of Magnetic Field for Preventing Membrane Fouling

• Main Authors: Jeng-Ming Li, 李振民
• Other Authors: 林正芳
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/87415146678069221877

碩士 === 國立臺灣大學 === 環境工程學研究所 === 95 === 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.