Study of [Bmim]Cl/LiCl Co-Solvent Dissolution of Waste Wool

Abstract

Waste wool was subjected to dissolution using an ionic liquid solvent, 1-butyl-3-methylimidazole chloride salt ([Bmim]Cl), with lithium chloride (LiCl) as an additive. This study’s objective was to examine the impact of LiCl on keratin’s solubility in [Bmim]Cl and characterise the structure and properties of keratin post-dissolution and regeneration. The results indicated that LiCl exhibits efficient solubility in [Bmim]Cl, enhancing keratin dissolution. Investigations employing Infrared, XRD and small-angle X-scattering spectroscopy, along with SDS-PAGE, demonstrated a degradation of the α-helical keratin structure during the dissolution process. This was accompanied by a reduction in molecular weight; however, keratin retained its protein nature. Atomic force microscopy (AFM) results revealed that keratin could proliferate on the slide surface or establish a continuous film. An integrative analysis suggested that wool protein macromolecules could be deconstructed by [Bmim]Cl and LiCl actions, inducing minor structural alterations in wool. This study proposes a groundwork for future research into keratin’s adsorption behaviour on textile materials, without significantly modifying the wool keratin structure or function.