Waste upcycling into High-Value MOFs: A Path toward direct Urban mining and sustainable resources recovery

The rapid growth of industrial activities and urbanisation has generated vast amounts of solid waste, while also increasing the demand for sustainable and functional materials. This highlights the urgent need for strategies that can transform waste streams into valuable resources. Waste streams already contain the essential components required to synthesize valuable metal-organic frameworks (MOFs): metal ions, organic linkers and structure-directing auxiliaries. This review consolidates studies of this emerging field that took off five years ago and organises "waste-to-MOF" routes into three categories aligned to practice: (i) metals from waste to MOFs; (ii) linkers from waste to MOFs; and (iii) waste as a template, support, solvent or auxiliary. A table of recent studies provides the most comprehensive and systematic overview to date of current trends in waste-to-MOF research. This review maps synthesis windows and phase-selection rules onto applications such as water treatment, energy storage/conversion, catalysis and emerging uses, as well as connects methods to metrics such as Process Mass Intensity (PMI), Environmental Factor (E-factor), solvent recycling and energy intensity. Using a techno-economic/environmental lens, this review also highlights the dominant levers. Also, four cross-cutting challenges namely feed variability and impurity control; scale-up/EHS frictions; metrics and standards gaps; and performance reproducibility, are identified. Finally, this review outlines future directions, including establishing reporting standards; designing with variability in the loop; intensifying and greening unit operations; and running profitable pilots with open mass and energy balances. The result is a concise playbook for converting diverse wastes into auditable, scalable MOF syntheses with application-relevant performance.