A Tutorial Mini-review on Crown Ethers Towards Rhodium Separation: Application of Crown Ether Studies
Abstract
Metallic resources are generally obtained as raw materials from mines, and through a refining process, they are made into metallic materials. In recent years, however, the recovery of precious metals from so-called "urban mines," or waste, has become important due to resource quantity and cost issues. Therefore, this paper first attempts to provide an introductory explanation of crown ethers in supramolecular chemistry as a principle for their selectivity for metal ions. Keeping in mind the selective recovery of rhodium, which is industrially important but not in great demand, the role and conditions of "crown ethers" in column separation and solvent extraction are briefly summarized.