Sustainable Bleaching Process of Raw Cotton by TiO2 Light-Activated Nanoparticles

Abstract

Nanoparticles (NPs) of titanium dioxide (TiO2) are promising for the photocatalytic degradation of organic compounds, arising as an excellent alternative to conventional bleaching processes. Within this background, aqueous suspensions of TiO2 NPs were impregnated by the pad-dry method in raw cotton. The hydrophilic properties and whiteness index (WI) of Berger were the main parameters examined before and after the TiO2 treatment. In the absence of water, using a UV-Vis lamp, high hydrophilicity was found for raw cotton. Diversely, under UV-LED radiation, the presence of water molecules in the coated cotton was revealed to be a crucial parameter in enhancing its whiteness. A comparable WI of Berger with conventional bleaching methods was obtained using 0.5 g L-1 TiO2 suspension under UV-LED radiation, suggesting that the impregnation of TiO2 NPs can be a promising alternative for the industrial bleaching methods, as it proves to be more sustainable and with low operating costs.

Keywords

• titanium dioxide
• cotton
• photocatalysis
• bleaching
• cleaning