Valorization of bio-colorants extracted from L. plant for sustainable and ecological coloration of wool yarns.

Recently, natural dyes are being explored all over the world as safer and highly sustainable bio-based alternatives to synthetic dyes. Agricultural wastes and plant by-products are the most commonly explored alternatives with dual benefits of waste reclamation and sustainable dye production with extra value-adds. plant contains interesting bio-dye molecules with high flavonoids and tannin contents. The present study aims at exploring the potential of plant extract to color wool textiles with a focus on sustainable bio-dye production and fastness properties. The extracted bio-dye was quantitatively (for total phenolic (2.733 mg per CE/g) and total flavonoid (1.140 mg per GAE/g) content using the Folin-Ciocalteu method) and qualitatively (UV-Vis, FT-IR, and EDX) characterized. The effect of dyeing parameters like pH (2-8), temperature (60-90 °C), dry-weight content of plant material as a dye (25-150% o.w.f.), and dyeing time (15-120 min) on color strength (K/S) values were assessed. Color fastness assays showed good resistance to light, washing, and rubbing. The effect of artificial aging (Xenon arc lamp) on the color strength of dyed wool yarns under different exposure times (0-48 h) was explored. The highest color fading occurred in control dyed samples with a first-order rate constant of 131.57 h and a half-life period of 5.26 x 10 h. Color difference (ΔE) values suggested that mordanted samples showed less fading compared to control dyed samples at equal times of Xenon exposure. Additionally, the dyed samples were washed in double distilled water, tap water, and 4 g/L NaCl solution to check their effects on the corresponding K/S values while 4 g/L NaCl solution mimics the real conditions of perspiration. Maximum color leaching occurred in 4 g/L NaCl washing with a first-order rate constant of 11.57 min. Cost analysis of the dye extraction and dyeing procedure revealed that the process is sustainable and economical. Thus, the use of whole plant can provide a clean, economical, and sustainable source of alternative natural dyes that can be used to substitute synthetic analogs.