pH值對具分散反萃取相支撐式液膜分離之影響及其數學模式分析

Abstract

近年，因其低耗能以及操作簡便性，支撐式液膜廣泛被使用於分離回收金屬離子，同時也有許多用於描述物質於支撐式液膜輸送的理論模型被提出。本研究提出一較為簡化的理論模型對具分散反萃取相支撐式液膜分離回收釹、鏑金屬離子進行預測，並由單一金屬離子的實驗求出參數。實驗得出鏑離子的平衡常數為35841.3、水相質傳係數為7.016×10-6m/s，錯合物於膜相質傳係數為4.301×10-7m/s；釹金屬離子的平衡常數為16.7、水相質傳係數為9.665×10-6m/s，錯合物於膜相質傳係數為3.430×10-7 m/s。理論模型在雙成份系統對於pH值改變及萃取劑濃度改變有好的預測，此較為簡化的模型將利於預測系統放大。

The use of supported liquid membrane to separate metal ions has been widely reported for its efficiency and simple process. Mathematical models for this technique have been proposed to describe the transport behavior. In this work, a simplified model for the separation of Dy3+ and Nd3+ through supported liquid membrane with strip dispersion (SLMSD) is established and the situation of excess amount of metal ions is considered. Parameters were calculated based on single-ion experiment. For Dy3+, the equilibrium constant was found to be 35841.3, the hydraulic mass transfer coefficient 7.016×10-6m/s, and the mass transfer coefficient of the complex in the membrane phase 4.301×10-7m/s. For Nd3+, the values were 16.7, 9.665×10-6m/s, 3.430×10-7m/s respectively. The model showed good agreements in Dy3+/Nd3+ separation experiments in various pH value and extractant concentration. The simplicity of the model gives an advantage on scale-up process.