Programming Ion Transport in Layered 2D Hybrid Membranes via Coordination‐Occupation Coupling

ABSTRACT The sustainable separation of chemically distinct yet notoriously difficult‐to‐separate metal ions is a critical challenge for nuclear waste management and strategic resource recovery. Layered two‐dimensional (2D) membranes offer energy‐efficient alternatives to conventional extraction and adsorption technologies, yet their selectivity is often constrained by fixed and poorly tunable transport pathways. Here we introduce a coordination‐occupation‐coupled strategy to program ion transport in layered 2D hybrid membranes combining a confined polyacrylate network between layered vermiculite. Irreversible crosslinking with Al 3+ ions within polyacrylate network forms unexchangeable coordination sites that stabilize the membrane structure and selectively occupy transport pathways for multivalent ions. This targeted pathway occupation suppresses the transport of Sr 2+ , La 3+ and Zr 4+ , while allowing Cs + to permeate efficiently through alternative routes. The resulting membranes achieve Cs + /Sr 2+ separation factors approaching 10 3 and near‐complete separation of Cs + from trivalent and tetravalent ions. This work establishes coordination‐occupation coupling as a scalable and material‐efficient principle for high‐selectivity ion separations, with direct implications for sustainable radionuclide remediation and critical metal recovery.