Sustainable waste textile upcycling by selective dye decoloration using ionic liquid and Bi11VO19 photocatalyst

Since a large amount of waste polyester-cotton blended textiles can cause environmental pollution problems, it is crucial to develop sustainable technology for recycling textile wastes and producing value-added products. In this research, regenerated cellulose and polyester were obtained from the polyester-cotton jean wastes by a sustainable process through the selective dissolving of cellulose fibers using an ionic liquid (ILs), 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). We developed an environmentally benign decoloration approach without the bleaching or leaching processes. Instead, cellulose, polyester, and ILs were recycled from the selective degradation of indigo carmine (IC) or indigo dye in the dye/ILs solution using the Bi11VO19 photocatalyst without impairing the dissolution capability of ILs. The selective decoloration of dye solution extracted from waste textiles involves interactions among photocatalysts, colorants, fibers, and media (ILs). The changes of dye and ILs molecules during the photocatalysis reaction were analyzed. FTIR and Raman spectra of the recycled ILs reveal that the chemical structure of ILs remains unchanged after the photocatalytic decoloration process. The ILs and photocatalysts can be recycled for repeated production of regenerated cellulose from waste jeans.