利用水溶性錯合物以離子交換回收與分離金屬離子

Recovery and separation of metal ions through ion-exchange membranes using water-soluble complexing agents

顏國雄(Gwo-Shyong Yan)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(2000年)

摘要

本論文係在不同水溶性錯合劑與電流密度下，利用離子交換膜分離金屬離子，探討各變數對金屬分離效果的影響。在濃度差和外加電場的影響下，金屬離子由陽極液通過薄膜至含有錯合劑的陰極液時，與錯合劑錯合，根據錯合劑對不同金屬離子的選擇性，以達到分離的效果。此外，並利用Nernst-Planck equation針對濃度與電流密度的影響討論。
在不加電場的系統中，金屬的質傳速率會隨著金屬初濃度(0~18 mol/m3)與錯合劑濃度(0~20.8 mol/m3)的增加而增加，而雙成分中分離係數(Cu/Ni)也會隨著增加。另外，因為EDTA對銅與鎳的穩定常數都大於PEI，所以EDTA對於提高金屬的質傳速率方面優於PEI。
在定電流系統中，金屬離子的質傳速率會隨著電流密度(0~185 A/m2)的增加而增加。而固定電流密度之下，增加錯合劑與金屬濃度，金屬質傳速率也會隨之上升。但是對銅鎳分離比例而言，增加電流並不會增加分離的效果。另外，電流對質傳速率的影響比例，會隨著電流密度的上升而增加。

關鍵字

錯合物 ； 離子交換膜 ； 回收金屬離子 ； 透析 ； 電透析

並列摘要

The effectiveness of metal separation under different complexing agents and current density using cation-exchange membrane has been sutdied. Metal ions were transferred through the membrane from feed solution to the receiving solution which contains complexing agents in different metal concentrations and variable voltage. The separation was achived by the selectivity of complexing agents to different metal ions. And, the effects of metal concentration and current density on the mass transfer rate were discussed by Nernst-Planck equation.
In the systems without applied voltage, the mass transfer rate increased with the concentrations of metals and complexing agents. This is also in the case of binary systems. EDTA was better than PEI in increasing the mass trasnsfer rate since the stability constants of metals and EDTA were larger than PEI. The mass transfer rate increased with the current density with applied voltage. In constant current density, increasing concentrations of the complexing agents and metals, led to an increase in the mass transfer rate.

並列關鍵字

complexing agents ； ion-exchange membrane ； dialysis ； electrodialysis

參考文獻

Cussler E.L. " Diffusion, mass transfer in fluid sysytem", 2nd ed. 1997.

Davis J. C., Valus, R. J. and Lawrence, E. G. "Affinity dialysis-method of continuous, rapid metal ion separation using dialysis membrane and selective, water-soluble polymers as extractants.", Sep. Sci. Technol., 23, 1039-1066, 1988.

Dutta N. N., Ghosh A. C. and Brothakur S., "Extraction of cephalosporin C using supported liquid membrane", Sep. Technol, 5, 121-126, 1995.

Eduardo E., Marina I., and Jesus I., "Removal of heavy metals in wastewater by electrochemical treatment", Chemical engineering education. 172-176, 1999.

Eyal A., Kislik V., "Aqueous hybrid liquid membrane-A novel system for separation of solutes using water-soluble polymers as carriers.", J. Membrane Sci., 161, 207-221, 1999.