Natural Chitin/Protein Nanofibrils Isolated from Crab Shell As a Green Platform Constructing a Hydrogel/Aerogel for Environmental Remediation.

Chitin/protein nanofibrils are extracted from decalcified crab shells using 100 mM hydrochloric acid and ultrasonication or high-pressure homogenization, achieving a 94% recovery rate. Further increases in the temperature or duration enhance hydrolysis, leading to a significant reduction in the nanofibril size. The increase in the number of acidic amino acids within the nanofibrils enhances electrostatic repulsion, promoting their dispersion under acidic conditions. This unique dispersibility enables the use of acidic/alkaline gas phase coagulation and ice-templated cross-linking for hydrogel construction. The protein content is believed to support efficient cross-linking between formaldehyde and the nanofibrils, resulting in aerogels that exhibit excellent adsorption properties, with capacities of 840.0 ± 84.2 g/g for water, 168.8 ± 8.9 g/g for pump oil, and 183.1 ± 2.6 g/g for cinnamon oil. The methodology utilized in this study demonstrates enhanced economic viability and simplicity compared with previously reported aerogels, showing significant potential for more practical and widespread applications.