Preparation and characterization of bio-inspired full-biomass-derived aerogel with vertically aligned structure

Using renewable biomass resources to prepare porous materials can reduce the dependence on petroleum-based energy, promote green, low-carbon, and high-quality development, and achieve carbon neutrality. Here, we report a bio-inspired full-biomass-derived aerogel with an ultra-light (10.33-27.77 mg/cm3), highly porous (98.66-99.19 %), and vertically aligned structure. The fabrication involves an ultrasonic-assisted deep eutectic solvent (DES) extraction of cellulose nanofibrils (CNFs)-blending-directional freeze-drying-hydrophobic modification. Initially, CNFs were extracted from corncobs using DES pretreatment. Then, the aerogels were prepared by co-mixing CNFs with alkali lignin and freeze-drying the precursor suspension using the ice-templated method. Finally, the aerogels were modified using trimethoxymethylsilane chemical vapor deposition to render them hydrophobic. The silanization-modified aerogels exhibited superior static and dynamic hydrophobic properties, with a water contact angle of up to 153.4 degrees, and demonstrated self-cleaning properties. These aerogels exhibited adsorption capabilities for various oils and organic solvents (9.6-29.8 g/g) and the ability to separate oil-water mixtures and adsorb methylene blue. Moreover, the aerogels with vertically aligned structures exhibited exceptional axial compression properties (up to 959 kPa), more than four times greater than the radial compression properties. Furthermore, the aerogels exhibited rapid liquid transport properties, with an axial transport rate of soybean oil that was more than 10 times higher than the radial transport rate. This study provides a green, eco-friendly, and sustainable strategy for preparing 3D porous aerogels, paving the way for developing full-biomass-derived aerogels as a promising alternative to petroleum-based adsorbent materials.