Highly Hydrophobic All-Biomass Aerogels with Advanced Oil Absorption and Recyclability

Biomass resources are abundant, diverse, and widely available in nature. The renewable and environment-friendly nature of biomass resources is in line with the theme of sustainable development of society. Herein, we report a facile and environmentally friendly route to prepare highly hydrophobic biomass aerogels for the adsorption of oil and organic solvents. The main features of our preparation approach are reflected by the use of natural animal gelatin and water-soluble chitosan as raw materials and dialdehyde carboxymethyl cellulose (DCMC) as a cross-linking agent through effective cross-linking between the aldehyde group and amino group, followed by hydrophobic coating of natural wax to create an entire biomass-based hydrophobic aerogel. The results showed that the WC-Gel/CMCS/DCMC aerogel had low density (12.3 mg/cm3), high porosity (>95%), and high hydrophobicity (144.2°). In addition, the aerogel can rapidly and selectively adsorb oil substances in oil–water mixtures and has a high absorption capacity (27.5∼46.2 g/g). The adsorption–extrusion repeated tests showed that the material has good adsorption performance and recyclability for various oil-containing liquids and organic solvents. Overall, the as-prepared biomass composite aerogel has great potential for application in the field of oil–water separation. The constructive concept of preparing composite aerogels by a simple method using biomass substrates also provides ideas for the development of biomass-based functional materials.