Polymer inclusion membranes for the extraction of rare earth elements

The demand for rare earth elements has increased significantly due to potential industrial applications such as catalysts, magnets, battery alloys, ceramics. However, the separation and recovery of rare earth metals are very difficult due to their similar chemical properties and ionic radius, so progress in the separation process of these elements will bring many global benefits. Among the improved methods, the membrane technique has received much attention as a stable method with easy operation in the separation of such metals, and several membranes have been designed for separation. This article provides a summary of the types of membranes in the separation of rare earth elements in terms of extraction performance, transfer efficiency, and membrane stability. Polymer inclusion membranes are a new generation of non-liquid membrane that is made by a simple method of casting a solution containing liquid phases (carrier, plasticizer /modifier) and base polymers. Polymer inclusion membranes due to the possibility of simultaneous extraction and back-extraction, high selectivity, excellent stability, reusability, simple applicability, relatively low cost, and low energy consumption, it provides a great advantage in both the separation and purification of metal ions. Therefore, in this study, an overview of the PIMs reported in the studies to date is presented and the performance, permeability and stability of the membrane are discussed according to the base polymer, carrier, plasticizer and modifiers used.