Mechanochemistry in Waste Valorization: Advances in the Synthesis of Catalysts, Polymers, and Functional Materials

The growing accumulation of waste from diverse human activities has intensified the search for sustainable strategies. Mechanochemistry offers a promising pathway, transforming residues into high-value products with reduced energy demand, shorter reaction times, and minimal use of solvents and reagents. Various wastes—including biomass, food residues, fly ash, used batteries, and halogenated polymers—can be converted into environmental adsorbents, industrial biopolymers, biocompatible compounds, electrodes, and catalysts. Unlike previous reviews that addressed specific waste streams, this study provides the first systematic and comparative analysis of mechanochemical valorization across multiple residues, following PRISMA guidelines (2000–2025). A total of 656 studies indexed in Scopus and Web of Science were evaluated. This integrative approach highlights recent advances, current challenges, and future prospects, offering a rigorous and transparent guide for scaling mechanochemistry toward circular and sustainable solutions.