Underwater in-situ plasma treatment of coarse wool fibers for scouring and bleaching

Wool, in its natural state, is laden with impurities such as grease, suint, dust, and vegetable matter on its surface, necessitating their removal for the wool to be suitable for various products. Traditional scouring methods involve the extensive use of water, detergents, and chemicals, leading to the generation of hazardous wastewater. Moreover, coarse fibers often require bleaching due to the retention of natural pigments during the scouring process. This study introduces an innovative and environmentally friendly plasma treatment for scouring and bleaching of the coarse wool fibers, referred here after as underwater in-situ plasma treatment (UIPT), which is entirely free from chemicals and detergents. Research includes a comparative analysis of UIPT, plasma-activated water (PAW), normal water (NW) and conventional wet-chemical process (CWP) for wool fiber scouring and bleaching. Surface morphology and surface chemistry analyses underscore the efficacy of UIPT in cleaning the coarse wool. The residual grease analysis demonstrated a substantial reduction in grease content of raw wool from 20% to 2% after plasma treatment, while the whiteness index of wool fibers increased from 48% to 70%.