Sustainable Dyeing and Mordanting of Silk with a Binary Colorant from Agro-Waste Material

The use of agro-waste materials as an alternative to synthetic dyes has gained considerable interest in the development of sustainable textile coloration. This study investigates the utilization of binary colorants from agro-waste sources such as harmal seeds and thuja leaves for silk, with statistical selection of variables. A central composite design (C.C.D.) coupled with microwave radiation was employed to select the significant dyeing conditions for excellent yield. It has been found that the pH 3 extract obtained from 6 g of binary powder after irradiation for 3 min, when applied at 75 °C for 40 min, produced an excellent yield of up to 6.15 (K/S). Two-way ANOVA also revealed the significance of selected dyeing variables for silk coloration using a binary colorant. The use of optimum amounts of chemical and bio-mordants produced colorfast, stable shades with fastness ratings of 4/5-5 for light, washing, and rubbing. The improvement in functional properties such as antioxidant and antibacterial properties of both the extracts and dyed fabric after MW treatment reveals that this bi-colorant has potential benefits for the community. It has been concluded that sustainable mordanting of silk has added more value in the coloration of silk with binary colorants by producing colorfast shades upon dyeing using statistically selected variables.