Extraction and membrane transport of lanthanides with dynameric constitutional framework carriers

Abstract

Dynamic covalent polymers or dynamers, generated from reversibly interacting monomers, offer the possibility to generate molecular-controlled materials with addressable domains which are different from these of former monomers and based on structural relationships between the network components. Herein, constitutional dynamic frameworks of Jeffamine-type macromonomers cross-linked via trifunctional core centers have been used as a dynameric-electrolyte network in liquid and solid membrane systems for lanthanide recognition, extraction and transport. The transport is based on the partition ability of lanthanides (La+3, Lu+3, and Eu+3) within functional dynameric network bearing polyether and imine groups. Interestingly, the lanthanides are extracted and selectively transported through the membrane, only in the presence of constitutional cross-linked frameworks, while the former Jeffamine monomers have been shown high extraction yields, but any selectivity. This would be explained by the formation of molecularly addressable recognition “pockets” in which the recognition/diffusional selective percolation pathways might exist. It implies that such dynameric frameworks have high selectivity towards La+3, Lu+3 relative to Eu+3 that may be separated.