Even though previous works have demonstrated the dissolution of feathers in ionic liquids, there is yet no effective way to separate the protein from ionic liquids. Therefore, the reusability of ionic liquid [HOEMIm][NTf2] was investigated under the optimum
conditions mentioned above. In our study, extracted keratin has good solubility in water, while [HOEMIm][NTf2] is immiscible with water. Consequently, keratin could be easily separated from the reaction mixture by water, and the extracted keratin could
be purified by dialysis and precipitated by ethanol according to requirement of final product. The remaining ionic liquid could be used directly in the next time. As shown in Fig. 2, the ionic liquid was used forfive batches without essential loss inthe process of dissolving
feathers. It was also found that the recovery of ionic liquid was about 95% in each cycle. This indicated that [HOEMIm][NTf2] is an effective hydrophobic ionic liquid for extracting keratin from chicken feathers.