Robust micro-nano hybrid aerogel derived from waste resources for thermal management and high-efficiency adsorption

Ultra-low density nanoaerogels as the lightest solid material have aroused extensive attention. However, lacking crack extension resistance limited their further development and application. Here, aramid and cellulose wastes were recycled to prepare high value-added nanofibers, which were further self-assembled to construct multilfunctional hybrid aerogels. In-situ growth of zeolitic imidazolate frameworks-8 (ZIF-8) on the cellulose nanofiber (CNF) created a robust skeleton. Flexible aramid nanofibers (ANF), as burgeoning building blocks were employed to inlay into the microscopic skeleton structure for establishing micro-nano double networks. Benefiting from the existence of multiscale networks, the maximum value in the compressive stress of S₀, S₁, S₂ and S₃ increased from 2.74 to 4.63, 5.19 and 6.61 MPa, respectively. Meanwhile, ANF-ZIF-8-CNF hybrid aerogels exhibited low thermal conductivity of 3.58–3.97 × 10^-2 W/(m⋅K). The significant increase in the specific surface area (481.46 m²/g) endowed hybrid aerogels with high adsorption abilities for nitrogen (280.83 cm³/g), prussian blue (34.12 mg⋅g⁻¹), rhodamine B (37.30 mg⋅g⁻¹), DMF (25.13 g⋅g⁻¹) and DMSO (15.48 g⋅g⁻¹), respectively. This multiscale structural engineering strategy opens an avenue toward to upcycle waste resources into the next-generation high-performance nanoaerogels, showing huge application potential in thermal management, air purification and sewage treatment.