Straightforward and selective metal capture through CO2-induced self-assembly

A new process of rare earth metal capture employing carbon dioxide as a key component was designed and studied. Proof of the feasibility of spontaneously self-assembling into a supramolecular solid from low-cost and readily available building blocks, including rare earth metals as templates and carbon dioxide as a molecular trigger, was investigated. The process proved to be selective for rare earth metals and reversible under mild and sustainable conditions. The impacts of chemical parameters such as metal-ligand stoichiometry or concentration of the mixture were studied both on the macroscopic and microscopic level. Finally, this new molecular system was tested on bimetallic mixtures involving metals used in permanent magnets, confirming the promising aspects of the technology.