Thermally Insulating Cellulose Nanofiber Aerogels from Brewery Residues

Brewery spent grain (BSG), the main waste of brewery industry, is often disposed or sold as an animal feed at low prices, neglecting potential for further valorization. In this work, BSG was used first time to produce cellulose nanofiber aerogels green thermal insulating applications. Cellulose nanofibers (CNFs) were extracted from through microfluidization with and without TEMPO-oxidation pretreatment obtain bio-based building blocks aerogels. The TEMPO-treated CNFs exhibited a finer diameter (5.4 nm) more homogeneous size distribution (2–10 than that nonoxidized samples. All produced demonstrated densities (0.009–0.031 g/cm3), conductivities (32.3–37.7 mW/mK), compressive Young’s modulus in range 4–311 kPa. Unidirectional freezing showed distinct improvement conductivity mechanical properties compared random frozen Specifically, unidirectional aerogel highest investigated CNF concentration 3 wt % lowest (32.4 (311 kPa), good stability. These results show BSG-derived nanocellulose valuable resource producing eco-friendly, biodegradable, thermally