Architected Ion Exchange Resins by Vat Photopolymerization 3D Printing for Rare Earth Elements Extraction

Architected sorbents that combine high surface area with customizable binding sites are attractive materials for liquid‐solid extraction of rare earth elements (REE) from hydrometallurgical feedstocks. Here, we report a family of rationally designed methacrylate‐based ion‐exchange resins (IERs) and evaluate their performance using a bastnaesite‐derived acid leachate. Bis[2‐(methacryloyloxy)ethyl] phosphate (BMPA) was selected as a dual‐function monomer that provides rapid photopolymerization and phosphate‐based ion binding, while di(2‐ethylhexyl) phosphoric acid (DEHPA) was incorporated as a non‐polymerizable component in the resin formulation to enhance REE uptake. In batch‐loading experiments, BMPA‐based resins displayed strong REE uptake, whereas a control group consisting of hexanediol dimethacrylate‐based resins performed poorly. With 20 wt.% DEHPA incorporated, the maximum total REE capacity reached 17 mg/g. Architected IERs were fabricated via vat photopolymerization 3D printing on a low‐cost desktop 405‐nm LCD printer. Lattice architecture enabled markedly faster apparent uptake than dense control groups, demonstrating the advantage of co‐designing resin chemistry and IER geometry. We expect that this co‐design strategy will provide a new platform for wide customization of solid extractants for diverse applications, such as mineral processing and wastewater treatment.