Turning Trash Into Treasure: Waste‐Derived Aerogels and Their Multifunctional Applications—A Comprehensive Review

Aerogels are renowned for their extraordinary nanoporous architecture and physicochemical properties. However, their widespread deployment is impeded by prohibitive production costs and intrinsic mechanical brittleness. Concurrently, the exponential accumulation of solid wastes ranging from agricultural biomass to recalcitrant plastics and tires has posed a critical threat to global ecological integrity. This review systematically elucidated the state‐of‐the‐art methods of valorizing diverse waste materials into high‐performance aerogels, championing a “waste‐to‐wealth” paradigm. Precursors derived from cellulosic, proteinaceous, polymeric, and inorganic residues are systematically classified, providing a critical analysis of microstructural tailoring via advanced sol‐gel and drying protocols. Emphasis is placed on the functional versatility of these recycled materials across five key types: efficient adsorption for environmental remediation, advanced thermal management for insulation and fire retardancy, mechanical engineering of leveraging the intrinsic elasticity of waste rubber to overcome brittleness, and emerging applications in acoustic damping and electromagnetic shielding. Notably, based on our research of rubber powder aerogels, we benchmarked these eco‐friendly alternatives against commercial standards to validate their industrial viability. The review concludes by identifying the “lab‐to‐fab” gap, highlighting the urgent need for standardized sources and scalable manufacturing to transition waste‐derived aerogels from academic novelties to sustainable engineering solutions.