Synergistic Nanoarchitectonics: Precision Membrane Engineering for Rare Earth Selective Separation

Abstract Rare earth elements (REEs) are vital in high‐tech industries and defense due to their strategic significance. Crafting an efficient membranes channel for REE separation poses a significant challenge. Employing 2‐methylimidazole‐hydrolyzed OH⁻, dopamine polymerization is initiated and then Zn²⁺ coordinates with 2‐methylimidazole on PDA surfaces. The confined symbiotic reaction yields 2D vertical heterojunctions of GO/ZIF‐8/PDA (G/Z/P). During separation, partially dehydrated smaller hydrated lanthanide ions preferentially access interlayers, expanding and stabilizing the interlayer space by coordinating with PDA, thus excluding larger hydrated scandium ions from the membranes. Some scandium ions entering interlayer channels are sequestered by N in size‐matched ZIF‐8 pores. This distinctive mechanism facilitates selective scandium separation from other REEs (other REEs/Sc selectivity ≈68.73), achieving nearly complete Sc³⁺ rejection in a single step. The methodology offers unprecedented insights into precise nano‐space material synthesis, indicating promising strides in advancing scandium production.