Multilayer Structure Ammoniated Collagen Fibers for Fast Adsorption of Anionic Dyes

Dye wastewater has become one of the difficult industrial wastewaters due to its significant characteristics such as high chroma and poor biodegradability. Here, we use collagen fibers (CFs) as the matrix, glutaraldehyde as the cross-linking agent, and polyethyleneimine (PEI) as the ammoniating modifier to prepare cationic-modified collagen fibers (CF-PEI). The CF-PEI still maintained the original fibrous structure with a larger adsorption area. The content of primary amino groups on CF-PEI was significantly increased, which not only improved the hydrophilic swelling performance of CFs but also improved the adsorption capacity. The adsorption capacity of CF-PEI for soap yellow and acid red could reach 538.2 and 369.7 mg g^-1, respectively. The adsorption rate was fast, and the adsorption equilibrium could be reached in about 60 min. Desorption regeneration studies have shown that 0.1 mol L^-1 HCl could achieve a better desorption effect, and the CF-PEI had a good recycling performance. The ammoniated modified CF-PEI was an excellent adsorption treatment material for anionic dye wastewater. It is expected to become an effective way for high-value resource utilization of waste dander in the leather industry.