Metal-organic frameworks for sustainable recovery of precious metals: Advances in synthesis, applications and multiscale mechanisms

The recovery of precious metals (PM) from secondary resources is critical for addressing global supply chain vulnerabilities and sustainable resource utilization. This review systematically examines the transformative potential of metal-organic frameworks (MOFs) as next-generation adsorbents for PM recovery, with a focus on synthesis strategies, functionalization approaches, and multiscale adsorption mechanisms. We critically analyze conventional pyrometallurgical and hydrometallurgical methods, highlighting their limitations in selectivity, energy consumption, and secondary pollution. In contrast, MOFs offer tunable porosity, high-density active sites, and tunable surface chemistry, enabling efficient PM capture through synergistic physical and chemical adsorption. Advanced modification techniques, including direct synthesis modification and post-synthetic modification, are reviewed to enhance the adsorption kinetics and selectivity for Au, Ag, Pt, and Pd. Key structure-property relationships are established through multiscale characterization and thermodynamic models, revealing the critical roles of hierarchical porosity, soft donor atoms, and framework stability. Industrial challenges such as aqueous stability and scalability are addressed via Zr-O bond strengthening, hydrophobic functionalization, and support immobilization. This work consolidates experimental and theoretical advances in MOF-based PM recovery, providing a roadmap for translating laboratory innovations into practical applications within the circular economy framework.