同軸圓管之電動現象分析與管膜
電荷量測

膜過濾已被廣泛應用，所遭遇的最大困擾是膜結垢而導致分離效能降低，其中除了膜孔徑及膜材之親疏水性等因素會影響膜結垢之程度外，膜材電荷在膜分離中亦扮演重要的角色，其是決定欲過濾物質與膜面相互作用力之主要變數，由此可知膜電荷的量測將有助於膜過濾時對膜材之選擇提供一重要的參考依據。膜電性之決定大多以H-S 模式關聯流線電位與壁面界達電位之關係，且目前大多以平板膜為主，但管膜已廣泛使用，卻未見文獻探討其量測方法。為建立管膜膜表面界達電位量測方法，本研究首先以理論分析同軸圓管之流線電位電動現象，並對同軸圓管之電動流方程及H-S電動模式修正因子進行分析，提出電動模式簡化式。本研究設計一套同軸圓管流線電位量測裝置，其以玻璃管為參考壁面，膜管置入其中，兩者形成同軸系統，藉由流線電位量測值配合所建立之電動模式，估算了三種管膜之外表面界達電位，所獲得之結果，除與文獻中相同膜材之平板膜獲得相同等電點外，針對同一管膜，三種不同管徑之玻璃管為參考壁面進行量測，亦獲得甚為一致之管膜界達電位，由此可証本研究所建立管膜測量系統之可行性。

關鍵字

管膜；電動模式；流線電位；界達電位

並列摘要

It has been recognized that the charge of membrane plays an important role in the performance of membrane separations, since the fouling and selectivity of the membranes are affected significantly by the nature and magnitude of the electrostatic interaction between the membrane and the charged components in feeds. Therefore, there is much interest recently in characterizing the membrane charge which is generally quantified in terms of zeta potential. It is well known that theoretical models relating the measurable electrokinetic quantities and the zeta potential are essential for membrane charge determination. So far, most studies on the zeta potential determination are aimed at flat membranes. Although tubular membrane has been widely used recently, but very few attentions has been directed to measure its charge. There is yet no method available for measuring the zeta potential of the outer surface of tubular membranes. In order to develop the technique to determine the outer surface zeta potential of tubular membrane, a theoretically electrokinetic model for the streaming potential in the annular space of concentric double-pipes with asymmetric surface charges was developed and a measuring system was also designed in the study. Since the theoretical model contains several parameters and is very complicated, the approximated relationships for the model was also derived to simplify the determination of membrane charge.. The measuring system designed used glass tubes as the reference wall and its zeta potential was determined first by measuring the streaming potential for electrolyte solution flowing through the tubes. Then the tubular membrane was placed into the glass tube and the streaming potential through the annular space was measured to determine the zeta potential of the outer surface of the membrane based on the theoretical model and the zeta value of the reference wall. Results from three different tubular membranes indicated the determined isoelectric points all agree with that reported for the materials composing the tubular membranes. On the other hand, the zeta potentials determined for a tubular membrane placed in three different radius glass tubes showed a well agreement. Based on these results, it can be concluded that the method developed in this study is available for determining the zeta potential of the outer surface of tubular membranes.

並列關鍵字

zeta potential ； streaming potential ； electrokinetic module ； tubular membrane

參考文獻

許惠如，“以電滲透及流線電位決定薄膜之界達電位”，碩士學位論文，中原大學化工所，（2002）

江宜蓁，“薄膜電荷量測與膜過濾電動現象分析”，碩士學位論文，中原大學化工所，（2003）

Afonso, M.D., Hagmeyer, G., Gimbel, R., “Streaming Potential Measurements to Assess the Variation of Nanofiltration Membranes Surface Charge with the Concentration of Salt Solutions,” Separation and Purification Technology , 22-23, 529-541（2001）

Ariza, M.J., Canas, A. J., Benavente, “Electrokinetic and Electrochemical Characterizations of Porous Membranes,” Colloids and Surfaces A： Physicochemical and Engineering Aspects , 189, 247-256（2001）

Polysulfone Membranes : A Comparative Study Between Two Different Experimental Systems and Determination of Electrokinetic and Adsorption Parameters,” J. Membrane Sci., 190, 119-132（2001）

國際替代計量

同軸圓管之電動現象分析與管膜電荷量測

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