According to full wavelength scan, [HOEMIm][NTf2] existed
maximum absorption peak at 217.5 nm, which mainly attributes
to imidazole ring in the ionic liquid. As shown in Table 1, the water
content of equilibrated [HOEMIm][NTf2] was 4.89%(w/v) and the
solubility of [HOEMIm][NTf2] in water was 7.941%(w/v), which
indicated that [HOEMIm][NTf2] was slightly soluble in water and
maximum recovery of it could be up to 96% (50% wt water, based on
the weight of ionic liquid). Moreover, [HOEMIm][NTf2] possesses
unexpected “hyperpolarity” close to protic ILs and water [20],
which could greatly enhance the dissolution of feathers. Therefore,
[HOEMIm][NTf2] was a proper ionic liquid for extracting keratin
from feathers.