A Fenton-assisted decolorization strategy for the cotton fabrics dyed with Reactive Blue KN-G

Abstract Decolorization is a vital step in the recycling and reuse of colored waste textiles. However, conventional textile decolorization methods often pose serious environmental and water resource pollutions. This paper presents a Fenton-assisted decolorization approach to strip the reactive dyes from cotton fabrics. In this research, reactive-dyed cotton fabrics were initially pre-treated with thiourea dioxide (TDO) and ferrous ions (Fe2+), followed by an oxidative decolorization treatment with hydrogen peroxide (H2O2). During these decolorization processes, dye molecules were gradually degraded through a series of reduction and oxidation reactions. The effects of process parameters on decolorization efficiency and the mechanical properties of cotton fabrics were investigated and optimized, including the dosage of decolorization agents, solution pH, decolorization duration and temperature. The results show that the proposed decolorization method efficiently removed reactive dyes from cotton fabrics quickly at a low temperature, achieving a decolorization rate higher than 90% with only about a 10% loss in the tensile strength. In addition, Fourier Transform Infrared Spectrometry (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) were utilized to investigate changes in the chemical composition, crystal structure, thermal stability performance, and surface microstructure of cotton fibers after decolorization as well as the possible decolorization mechanism.