The synchronized wash-off of reactive-dyed cotton fabrics and decolorization of resultant wastewater using titanium dioxide nano-fibers.

In this research, titanium dioxide (TiO2) nano-fibers with a well-organized anatase structure were synthesized by a hydrothermal method. Their structural properties were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and transmission electron microscope (TEM) analysis, respectively. Subsequently, the TiO2 nano-fibers were optically excited under the ultraviolet (UV) irradiation to decolorize the reactive dye solution. The influences of initial pH, concentrations of reactive dye and TiO2 nano-fibers as well as irradiation time on rate of photocatalytic decolorization were investigated. Based on their excellent photocatalytic performance, a novel method for achieving the synchronized wash-off of reactive-dyed cotton and decolorization of resultant wastewater was developed. It was found that the wash fastness of reactive-dyed cotton after TiO2-based wash-off was equal to that after standard way. The influences of TiO2-based wash-off on the properties of cotton substrates were determined by Fourier transform infrared spectroscopy (FTIR), XRD, and scanning electron microscope (SEM) analysis, respectively, which indicated that this new synchronized method would exert few damages to the cotton substrate.