117 / 2021-11-10 15:45:33

Green Approach to Facilely Design Hydrophobic Aerogel Directly from Bagasse

Aerogel, Bagasse, Hyrophobicity, Oil absorption, Thermal insulation

As a prevalent agricultural residue, bagasse is mostly combusted for energy. Aerogels are a kind of porous materials with three-dimensional network structure, which possess extremely low density, large specific surface area, high porosity and low thermal conductivity. Due to their unique properties, aerogels exhibited great application prospect in separation, adsorption, catalysis, sensing, energy storage, heat insulation and biomedicine, etc. Developing bagasse-based aerogels would prompt its application value. In the reported bagasse aerogels, bagasse is commonly treated by dissolution and regeneration or the removal of hemicellulose and lignin. These treatments would consume additional chemicals, which makes the preparation complicated and even environmental-unfriendly. Thus, it is highly desirable to develop a facile and green strategy to design bagasse-based aerogels.

In this work, hydrophobic bagasse aerogels were facilely prepared in an environmental-friendly strategy, including milling of bagasse, mixing with AKD emulsion, freeze drying and thermo-crosslinking. Interestingly, AKD behaved as strength agent to endow aerogels with lower density, higher porosity, and better strength in comparison with the pristine bagasse aerogel. Increasing the AKD or slurry concentration, their density and porosity increased and decreased, respectively, resulting in a normal distribution of oil absorption properties. The optimal hydrophobic bagasse aerogel was obtained at an AKD content of 10 wt% and a slurry consistency of 3 wt%, whose density, porosity and WCA was 47.3 mg cm^–3, 95.9% and 148°, respectively. It exhibited a high oil absorption capacity (31.65 g g^–1) and a low thermal conductivity (36.28 mW m^–1K^–1), which could be applied for oil/water or emulsion separation and thermal insulation especially under humid condition.. The fabrication method would provide a novel idea for other bio-based hydrophobic aerogels.