Development of efficient separation process of rare earth metals utilizing interfacial area

稀土金属的分离过程需要巨大的能量，因为稀土系列中相邻元素的分离非常困难。因此，需要一种提高分离效率的新方法来简化分离过程。在本研究中，我们开发了几种利用油水或固水等界面区域分离稀土金属的新技术，并获得了以下结果：1。开发了用于稀土金属选择性分离的新型增效剂。加入少量的助剂后，对稀土金属的选择性显著提高。增效剂与稀土离子在油水界面上相互作用的差异导致了分离效率的提高。等离子体接枝聚合技术使得用聚丙烯酰胺层修饰多孔聚四氟乙烯中空纤维膜的表面成为可能。采用等离子体接枝聚合改性中空纤维膜萃取器对稀土金属进行分离。当使用表面修饰膜时，接枝层与金属离子的相互作用提高了分离系数。经等离子体接枝聚合改性的中空纤维膜是一种非常有用的稀土金属分离材料。研究了一种新型的金属离子选择性树脂分子印迹技术。采用金属离子结合（主）单体、树脂基体形成共聚物和靶金属离子，通过乳液聚合制备表面模板化树脂。在这项研究中，我们利用这种新技术制备了几种金属离子印迹树脂。发现宿主单体的界面活性是产生印迹效果的关键因素。

The separation process for rare earth metals requires a huge energy, because the separation of adjacent elements in the rare earth series is very difficult. Thus a new method to enhance the separation efficiency is desirable to simplify the separation process. In this study, we have developed several new separation techniques for rare earth metals utilizing an interfacial area such as an oil-water or a solid-water, and the following results were obtained :1. New synergistic agents have been developed for the selective separation of rare earth metals. By the addition of a small amount of the agent, the selectivity of rare earth metals was enhanced remarkably. The difference in interaction between the synergistic agent and rare earth ions at the oil-water interface results in an increase in the separation efficiency.2. A plasma-graft polymerization technique made it possible to modify the surface of a porous hollow-fiber membrane of poly (tetrafluoroethylene) with polyacrylamide layr. Separation of rare earth metals was conducted in the hollow-fiber membrane extractor modified by plasma-graft polymerization. When the surface-modified membrane was used, the separation factor increased by the interaction between the grafted layr and metal ions. The hollow-fiber membrane modified by plasma-graft polymerization was found to be very useful as a separator of rare earth metals.3. A novel molecular imprinting technique has been developed for a metal ion-selective resin. A surface-templated resin is prepared by an emulsion polymerization using a metal ion-binding (host) monomer, a resin matrix-forming comonomer and a targer (guest) metal ion. In this study, we have prepared several metal ion-imprinted resins by the novel technique. The interfacial activity of the host monomer was found to be a key factor to produce the imprinting effect.