Corn Stalk-Derived Cellulose Aerogel/Poly(vinyl alcohol): Impact of Hydrophobic Modifications on the Adsorption Activity and Assessment of Thermal Insulation Perspective

Herein, the cellulose aerogel (CellA) material was synthesized from bulk cellulose derived from corn stalks with poly(vinyl alcohol) (PVA) as the binding agent. In detail, the influence of precursor mass ratio on the physicochemical properties and adsorption capacity of CellA was thoroughly investigated, which illustrated the cellulose:PVA ratio of 15:1 as the suitable fabrication of cellulose aerogel, with favorable density, porosity, and characteristic behaviors. The surface modification for the prepared CellA was also carried out using stearic acid and polydimethylsiloxane, followed by a carbonization treatment. The obtained results revealed that the 500 °C-carbonization of the stearic acid-coated sample exhibited superior adsorption capacity of cooking oil (32.98 g/g) as well as a high hydrophobicity with a wetting angle of 131.7°. Besides, the sample also provided a relatively low thermal conductivity at 0.067–0.069 W/m K within a surveyed temperature range of 40–50 °C. Conclusively, the environmentally-inspired CellA material highlights an effective utilization of corn stalks—an abundant biomass source via a facile preparation effort as an alternative candidate for the adsorption of non-polar organic compounds and thermal insulation.