Imidazole ionic liquid [Bmim]Cl can quickly extract keratin
from poultry feathers and the method is high efficiency not only
for treatment of waste feathers but also for recovery of high value
keratin. Comparing with the traditional method with strong acid or
alkali resulting in new pollutants, the solvent of IL is non-volatility
and easy recycling, thus there is no discharge of pollutants, which
accords with atom economy and is eco-friendly process. Furthermore,
the extracted keratin remains the same protein ingredient
and molecular size as those in the feather.
Na2SO3 can unfold disulfide bonds of cystine in keratin to
improve the process of dissolution of keratin from feather and it
recovers during keratin precipitation. Therefore, it is easily separated
from keratin, which not only benefits the recycling of Na2SO3
but also no effect on the quality of the extracted keratin. Water is
also beneficial to the extraction process owing to its main effects
on the dissolution of Na2SO3 and the decrease of viscosity. The
yield of keratin can attain 75.1% under extraction time of 60 min
at 90 C, with 20 wt.% of water in IL–water, weight ratio of
liquid/feather of 20, and 10 wt.% Na2SO3.