Colored TiO2 composites embedded on fabrics as photocatalysts: Decontamination of formaldehyde and deactivation of bacteria in water and air

This paper presents the fabrication of colored photocatalytic fibers by individually combining white TiO2 with red alpha-Fe2O3, green copper perchlorophthalocyanine (CuPcCl16), and blue copper phthalocyanine (CuPc), followed by immobilization of three as-prepared nanocomposites (i.e., Fe2O3/TiO2, CuPcCl16/TiO2, and CuPc/TiO2) onto the low melting point sheath-core composite polyester fibers (LMPET). The spectroscopic and surface measurements of colored fabrics show uniform distribution of the composites on LMPET fibers. Compared with TiO2-based white fabric, the prepared colored catalytic fabrics have better performance in photocatalytic degradation of formaldehyde (HCHO), a pollutant in water and indoor air. In addition, the prepared fibers could be recycled or reused without any appreciable decrease in their effectiveness. The investigation of antibacterial activity of colored fabrics shows 6-log inactivation of both Escherichia coli and Staphylococcus aureus. The enhancement in the photocatalytic activity of colored fabric is attributed to a broadening photo-absorption region and also a decrease in the recombination of electron-hole pairs. In the photocatalytic process, an increase in photocurrent response suggests the increase in charge separation. Additionally, hydroxyl radicals ((OH)-O-center dot) as the major reactive species in photocatalytic activity of colored fabrics are confirmed by the electron paramagnetic resonance technique. This study suggests that the developed colored photocatalysts can be applied in textiles to clean water and air.