Fabrication of superhydrophobic cellulose aerogel from peanut husk biomass for energy-efficient and environmental applications

The growing need for sustainable materials in the built environment has intensified interest in upcycling biomass waste into high-performance construction products. This study introduces a novel approach to valorize peanut husks, which is an abundant but underutilized agricultural residue, by extracting cellulose and converting it into multifunctional aerogels. Peanut husk-derived cellulose was combined with sodium alginate/CaCl 2 as a green gelation system, and aerogels with varying cellulose contents (2.5 %, 5 %, 7.5 %, and 10 %) were fabricated via freeze-drying. The samples were further surface-modified with methyltrichlorosilane (MTCS) using a chemical vapor deposition (CVD) method. The resulting aerogels exhibited low densities (0.047–0.130 g/cm 3 ), excellent thermal insulation (0.017–0.029 W m −1 K −1 ), and high decomposition temperatures (∼336 °C). The MTCS-CVD treatment produced superhydrophobic surfaces (contact angle >150°) with high solvent adsorption capacity (up to 16 × their weight). These results demonstrate a technically feasible route for producing multifunctional cellulose aerogels from agricultural waste, emphasizing material design and process optimization for sustainable applications in energy-efficient and environmentally friendly building materials. • Peanut husk biomass was upcycled into value-added cellulose aerogels. • Aerogels showed low density and high thermal insulation for green building use. • Superhydrophobic surfaces were achieved via eco-friendly CVD modification (WCA >150°). • Aerogels absorbed up to 16 times their weight in solvents aiding environmental reuse. • Dual use in thermal insulation and solvent recovery supports circular economy.