Applications of three-dimensional whey protein amyloid fibril-based hybrid aerogels in oil/water separation and emulsion separation.

Environmental contamination from oil spills and industrial wastewater poses long-term risks to ecosystems and human health. Amyloid fibrils' superior stiffness and stability, outstanding biocompatibility and biodegradability, versatile functional groups, and high specific surface area make them promising sustainable adsorbents. This study is aimed at examining the application of three-dimensional polysaccharide-modified whey protein amyloid fibril (WPIAF) aerogels in oil/water separation and emulsion separation. The WPIAF aerogel was first synthesized through the salting out method coupled with lyophilization, then modified using carboxymethyl cellulose (CMC) or chitosan (CS). Our results showed that WPIAF aerogels exhibited increased mechanical properties and surface hydrophobicity after polysaccharide modification. The CS-modified WPIAF aerogels showed better oil adsorption capacities, oil adsorption capability, and reusability than WPIAF aerogel and CMC-modified WPIAF aerogels. Furthermore, the applicability of polysaccharide-modified WPIAF aerogels in a continuous oil/water separation system was demonstrated. Finally, the separation efficiencies of polysaccharide-modified WPIAF aerogels were determined to be over 90 % in various emulsion systems, and the possible separation mechanism was further investigated. This study provides a nice example of applying amyloid-based aerogels for oil/water separation and emulsion separation.