Agricultural waste of Ipomoea batatas leaves as a source of natural dye for green coloration and bio-functional finishing for textile fabrics

Agricultural wastes are precious biomass resources that have been misplaced. This work aims to verify the usability of Ipomoea batatas leaves for simultaneous dyeing and functional finishing (anti-bacterial and anti-ultraviolet) of textile fabrics without the use of inorganic salts and metal mordants for the cleaner production of environmentally friendly value-added products. The optimal extraction conditions for natural dye were investigated by the single-factor analysis as ethanol/water (6:4) mixed solvent system with a material-liquid ratio of 1:10, a temperature of 90 ℃, a time of 1.5 h, and a pH value of 7. The adsorption kinetics study showed that the adsorption behavior of the natural dye on silk fabric was more consistent with the pseudo-second-order kinetic model and the Langmuir model. Meanwhile, the natural dye extracted from Ipomoea batatas leaves could be used for simultaneous salt-free dyeing and functional finishing of silk fabric and other fiber types with good color fastness, antibacterial properties and UV resistance with some durability, and the color strength in the order of wool, nylon, cotton, silk and polyester fabric. The outcome of this study can provide a possibility for the application of agricultural wastes in textile eco-dyeing and finishing, as well as the value-added management of green wastes.