Facile and green fabrication of biodegradable aerogel from chitosan derivatives/modified gelatin as absorbent for oil removal

Frequent oil spills have caused increasingly severe pollution of marine water bodies. As a result, exploring green and efficient aerogels to tackles oil pollution is in high demand. In this work, a unique strategy for preparing all-biomass aerogel was innovatively proposed. A series of all-biomass CW&BW@DCGA aerogels were successfully prepared by multiple dynamic covalent bonding, in which carboxymethyl chitosan (CMCS) as the substrate material, modified gelatin (Gel-ADH) as a reinforcing agent, and dialdehyde β-cyclodextrin (Da-β-CD) as a non-toxic cross-linking agent. The resulting aerogels were further hydrophobically modified with a green and natural wax blend consisting of carnauba wax (CW) and beeswax (BW). The experimental results demonstrated that incorporating Gel-ADH significantly improved the elastic properties of the materials. Specifically, when m(CMCS):m(Gel-ADH) = 7:3, the aerogel exhibited outstanding resilience, with 60 % compressive strain. In addition, CW&BW@DCGA displayed excellent hydrophobicity, boasting a water contact angle as high as 148.6°, and impressive absorption capacities ranging from 31.7 to 62.5 g/g towards different oils. Its adsorption capacity remained close to 70 % after 10 cycles, indicating favorable reusability. The dynamic absorption processes towards gasoline, diesel, and soybean oil were also well fitted with the pseudo-second-order kinetic model, suggesting that the process is primarily governed by chemisorption.