具分散反萃取相支撐式液膜處理廢稀土金屬離子溶液之技術開發
| 中文摘要 | 本研究為應用具分散反萃取相支撐式液膜於稀土金屬離子廢液處理技術開發，除探討其對稀土金屬離子之處理能力，並評估回收並濃縮廢液中釹(Neodymium, Nd3+)及鏑離子(Dysprosium, Dy3+)的技術。本研究使用D2EHPA、Isopar-L、硝酸鏑及硝酸釹分別作為分離系統中的萃取劑、稀釋劑以及進料稀土金屬溶液。本研究首先探討具分散反萃取相支撐式液膜中實驗參數與兩種離子透過係數的關係。實驗參數包括進料溶液的氫離子濃度、進料溶液的體積流速、有機萃取劑的濃度與反萃取劑的濃度。實驗發現當進料溶液中氫離子濃度越高，兩種離子的透過係數均會降低；在進料溶液低氫離子濃度的狀況下，流速越高透過係數會越高，但在進料溶液高氫離子濃度的環境時，流速對於透過係數沒有影響；有機萃取劑濃度上升時，兩種稀土離子的透過係數皆會隨之上升；另外反萃取劑濃度不會影響鏑/釹離子的透過係數。兩離子的分離實驗第一步驟中，將進料溶液控制於0.1M硝酸根、pH值1.15、進料體積流速為0.04 m/s、萃取劑5mM D2EHPA溶於isopar-L中、反萃取劑2M硝酸，結果顯示可在四小時內將鏑離子單獨地透過液膜，其透過係數達6.75×10-6 m/min，回收率達95.14%，濃縮效果從300 mg Dy3+/L至1420 mg Dy3+ /L。在第二步驟中，再將萃取劑濃度提高至50mM，其餘條件不變下，可將進料溶液剩餘的釹離子於四小時內進行萃取及高濃度濃縮，透過係數達1.26×10-5 m/min，回收率達92.62%，濃縮效果從300 mg Nd3+/L濃縮至1379 mg Nd3+ /L。經由此二階段的程序，可成功將釹/鏑兩離子加以分離並完成高濃度濃縮。本研究以進料溶液質傳-界面化學反應-液膜擴散三項串聯步驟描述兩離子透過液膜行為，並利用批式搖瓶實驗得到兩種金屬離子與D2EHPA的化學平衡常數，藉由改變具分散反萃取相支撐式液膜的實驗條件得到各個動力學模型參數，並得到動力學模型。離子透過液膜行為可由速率等於驅動力除上兩項阻力表示，由動力學模型可看出個別離子透過係數與水相中氫離子濃度、萃取劑濃度、進料相流速有關，在定量描述上也成功地預測混合系統中兩離子於具分散反萃取相支撐式液膜中的透過係數。 | ||
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| 中文關鍵字 | 具分散反萃取;支撐式液膜;鏑離子;釹離子 | ||
基本資訊
| 專案計畫編號 | EPA-102-U1U4-04-004 | 經費年度 | 102 | 計畫經費 | 1300 千元 |
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| 專案開始日期 | 2013/03/28 | 專案結束日期 | 2013/11/30 | 專案主持人 | 謝子陽 |
| 主辦單位 | 永續發展室(停用) | 承辦人 | 林燕柔 | 執行單位 | 中國科技大學 |
成果下載
| 類型 | 檔名 | 檔案大小 | 說明 |
|---|---|---|---|
| 期末報告 | 102環保署期末詳細版報告大綱(中國科大公開版).pdf | 0MB |
Removal of rare earth metal ions by using supported liquid membrane with strip dispersion
| 英文摘要 | The purpose of this study was to apply the supported liquid membranes with strip dispersion ((SLM-SD) technology on the separation and concentration of two rare earth metal ions, dysprosium and neodymium, from waste streams of the magnet industry. In this work, D2EHPA, Isopar-L, and aqueous neodymium and dysprosium nitrate solutions were used to be the extractant, diluent and feed solutions respectively in order to evaluate the separation efficiency of the support liquid membranes with strip dispersion process. Some parameters influencing on the permeability of dysprosium and neodymium ions including the acidity of feed solutions, flow rate in tube side, extractant concentrations, as well as stripping agent concentrations were investigated in detailed. Results indicated as acidity of feed solutions increased, the permeability of neodymium and dysprosium ions decreased. Besides, in weak acid condition, as the flow rate in tube side increased, the permeability of two ions increased. But in strong acid condition, there was no relationship between the flow rate in tube side and permeability of two ions. Additionally, as extractant concentrations increased, the permeability of neodymium and dysprosium ions increased. There was no relationship between stripping agent concentration and permeability. .In separation of neodymium and dysprosium ions, pH 1.15 in feed solutions, feed side flow rate 0.04m/s, 5mM D2EHPA dissolved in isopar-L, and 2M nitric acid as strip solution were used. The permeability of dysprosium ions was 6.75×10-6 m/min and 95.14% recovery was achieved. In this process, 300 mg/L Dy3+ were concentrated to 1420 mg/L after 4 hours operation. Enhancing D2EHPA concentration to 50mM in the second process, permeability of neodymium ions was 1.26×10-5 m/min and 300 mg/L neodymium ions were recovered. A 92.62% recovery and concentrated 1379 Nd3+ mg/L can be reached after 4 hours operation. The batch extraction experiments were carried out to determine the equilibrium constant for the formation of the extracted complexes. The SLM-SD transport model was presented in terms of the mass transfer behavior in the hollow fiber, chemical reaction of the metal and extraction on the feed-membrane interface, and diffusion of metal complex on the membrane phase. The kinetic parameters were calculated and successfully used to describe the permeation of two kinds of ions. | ||
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| 英文關鍵字 | Strip dispersion;supported liquid membrane;dysprosium;neodymium | ||