Adsorption of methylene blue dye on feather keratin/silk fibroin porous aerogels

Contaminated water resources and recycled wastes are serious global environmental issues. To conserve pure water resources, the elimination of harmful organic/inorganic pollutants from water is essential. Furthermore, massive amounts of discarded feathers not only increase environmental pollution but also lead to a waste of keratin resources. Therefore, the recycling of keratin is also of particular importance. As a natural polymer, keratin contains numerous active sites that can be applied as a biosorbent. In this study, deep eutectic solvent-extracted feather keratin (FK) was mixed into silk fibroin (SF) solution, and cetyltrimethylammonium bromide (CTAB) was added to prepare structurally homogeneous bio-based porous aerogels. The morphological structure, molecular conformation, mechanical properties of FK/SF aerogels were studied. It indicated that the EtOH treatment changed the molecular conformation from random coil to β-sheet and enhanced the overall compression strength of the aerogel. Using cationic dyes as simulated pollutants, the adsorption performance and kinetics of aerogels were investigated at various pH values, initial concentrations and temperatures. The results revealed that under the conditions of pH 7 and 45 °C, FK/SF aerogels treated with ethanol showed strong adsorption capacity with a maximum adsorption capacity of 163.84 mg/g at an initial concentration of 400 mg/L of MB dye.