ABSTRACT

Background: Supported liquid membranes (SLMs) and polymer inclusion membranes (PIMs) are an interesting technology for the recovery and separation of metal ions. This kind of membranes could provide the advantages of hydrometallurgy (i.e. high selectivity, possibility to treat low concentration of metals …) without needing a large organic solvent inventory.

Problem: However, the large-scale application of SLMs is limited because of the short lifetime of the process. Several authors claimed a longer lifetime when molecular diluents were replaced by ionic liquids (ILs).

Possible solutions: In this review, recent advances on the extraction of metals from aqueous solutions using SLMs and PIMs based on ILs are summarized and discussed. The mechanisms of degradation are reported and the improvements as well as limitations outlined. In SLMs, ILs were shown to improve membrane stability. However, stability is improved with viscous ILs having low solubility in water. ILs were used in PIMs as plasticizers and/or carriers and have shown their potential. However, the effect of ILs on PIM structure is not fully understood. To date, extraction of anionic metallic species is the most relevant field of study for SLMs and PIMs. A larger variety of ILs could be studied to apply this technique for a broader range of metals.

摘要

背景：支撑液膜 (SLM) 和聚合物包裹膜 (PIM) 是一种用于金属离子回收和分离的有趣技术。这种膜可以提供湿法冶金的优点（即高选择性，可以处理低浓度金属……），而不需要大量的有机溶剂库存。

问题：然而，由于工艺寿命短，SLM 的大规模应用受到限制。几位作者声称，当分子稀释剂被离子液体 (IL) 取代时，使用寿命会更长。

可能的解决方案：在这篇综述中，总结和讨论了使用基于 IL 的 SLM 和 PIM 从水溶液中提取金属的最新进展。报告了降解机制，并概述了改进和限制。在 SLMs 中，ILs 被证明可以提高膜的稳定性。然而，使用在水中具有低溶解度的粘性离子液体可以提高稳定性。IL 在 PIM 中用作增塑剂和/或载体，并已显示出其潜力。然而，ILs 对 PIM 结构的影响尚不完全清楚。迄今为止，阴离子金属物质的提取是 SLM 和 PIM 最相关的研究领域。可以研究更多种类的 IL，以将这种技术应用于更广泛的金属。