螯合劑存在對液態離子交換媒效能之影響

Effect of Complexing Agents on the Effectiveness of Liquid Ion Exchangers

朱華勳(Hwa-Shiun Ju)

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(1998年)

摘要

液態離子交換媒反應在工業上的應用十分的廣泛，最為常見的就是一般的液-液萃取反應以及相間轉移觸媒反應；這兩種反應有著相同的好處與相同的壞處；好處在於其可重複使用的特性與操作上十分簡易，而壞處在於其存於液相中較不易回收。我們根據其易於操作的特性，將之應用於廢水中螯合金屬離子的回收，並探討以酸性離子交換媒做為試驗對象。
本論文旨在探討酸性液態離子交換媒反應對螯合劑存在時的效能影響為何；我們以二（2-乙基己基）磷酸（D2EHPA）做為此處的離子交換媒，煤油為其稀釋劑，而我們藉由改變pH值、D2EHPA的濃度、螯合劑的種類、β值、初始離子濃度以及溫度來對整個反應的效能來作探討。文中我們是以 這個通式作為金屬與D2EHPA在有機相中的複合物，利用質量平衡與Mathematica這個套裝軟體來計算反應中所生成的物種濃度，並由此帶入複合物的通式之中，找出複合物的型式並推導出反應平衡常數Keq，並以此做為反應機構的判定。
由實驗結果中，我們可以得知在不同的pH值下會有不同型式的複合物產生，且平衡常數就會隨著而改變；另外，使用不同的螯合劑，也會使得平衡常數改變；在此，我們將這些變數分別討論之。

關鍵字

螯合劑 ； 離子交換 ； 液態離子交換媒 ； 萃取

並列摘要

The liquid ion-exchanger was used so usually in chemical process. The liquid-liquid extraction and phase transfer catalytic reaction were the most common types. These two kinds of reaction have the same advantages and the similar disadvantages；the advantages were that it can be reuse and easy to operate, the advantages was hard to recover in liquid phase. The acidic ion-exchanger was used here and was using in recovering the chelating metal in the industrial aqueous.
The affection of effective of chelates existing in acidic ion-exchange reaction was studied in this paper. Di（2-ethylhexyl）phosphate （D2EHPA）was used as ion-exchanger and kerosene was used as diluent. The effects of the pH values, the concentration of D2EHPA, the kinds of chelates , the b values, the concentration of metal ions, and the temperature on the ion-exchange equilibrium were studied. The equilibrium data were numerically analyzed by Mathematica 3.0 based on mass balance equations. It was shown that the ion-exchange reactions could be described by assuming the formation of metal complexes with the general composition . And using this formation to find the Keq, equilibrium constant, and to define the reaction mechanism.
By the results of the experiment, the equilibrium constants were gotton with the different pH values. And the operating conditions about different kinds of chelates of the experiment were discussed.

並列關鍵字

complexing agent ； ion exchang ； liquid ion exchanger ； extraction

參考文獻

Alonso,H.E and Chen, P.H., "Remediation of metal contaminated soil by EDTA incorporating electrochemical recovery of metal and EDTA, "Environ.Prog., 12（4）, 284-93（1993）.

Chiles, M. S.,D. D. Jackson, P. C. Reeves, Preparation and Synthetic Utility of Phase Transfer Catalyst Anchored to Polystyrene, J. Org. Chem., 45, 2915.（1980）.

Davies, C. W.,"Ion Association", Butterworths, London（1962）.

Flett, D. S., "Solvent Extraction in Scrap and Waste Processing" , J. Chem. Tech. Biotechnol., 29, 258-272 (1979).

Forrest, C., and Hughes, M. A., Hydrometalurgy, 1（2）,（1975）.