High-efficiency dysprosium-ion extraction enabled by a biomimetic nanofluidic channel.

Abstract

Biological ion channels exhibit high selectivity and permeability of ions because of their asymmetrical pore structures and surface chemistries. Here, we demonstrate a biomimetic nanofluidic channel (BNC) with an asymmetrical structure and glycyl-L-proline (GLP) -functionalization for ultrafast, selective, and unidirectional Dy³⁺ extraction over other lanthanide (Ln³⁺) ions with very similar electronic configurations. The selective extraction mainly depends on the amplified chemical affinity differences between the Ln³⁺ ions and GLPs in nanoconfinement. In particular, the conductivities of Ln³⁺ ions across the BNC even reach up to two orders of magnitude higher than in a bulk solution, and a high Dy³⁺/Nd³⁺ selectivity of approximately 60 could be achieved. The designed BNC can effectively extract Dy³⁺ ions with ultralow concentrations and thereby purify Nd³⁺ ions to an ultimate content of 99.8 wt.%, which contribute to the recycling of rare earth resources and environmental protection. Theoretical simulations reveal that the BNC preferentially binds to Dy³⁺ ion due to its highest affinity among Ln³⁺ ions in nanoconfinement, which attributes to the coupling of ion radius and coordination matching. These findings suggest that BNC-based ion selectivity system provides alternative routes to achieving highly efficient lanthanide separation.