The purpose of this research is to evaluate the colouring performance of Amba Haldi-based natural extracted yellowish colour for the dyeing of wool fabric using ultrasonic (US) treatments. Before and after the US treatment, the colourant was separated in aqueous and acidic solutions for up to 60 min. Scanning electron microscopy and Fourier-transform infrared spectroscopy were used to investigate the surface morphology and chemical changes in the cloth before and after radiation. On the wool fabric that was ultrasonically treated at 75°C for 45 min, an acidic extract of Amba Haldi powder after US treatment for 20 min showed good colour depth (K/S). Acacia extract (2%), pomegranate extract (1.5%) and pistachio extract (1%), when used as pre-biomordants, were shown to have excellent colour strength. Acacia (1.5%) extract, pomegranate (2%) extract and pistachio (1.5%) extract were also used as post-biomordants. As pre-chemical mordants, Al salts (1%), Fe salts (1.5%) and tannic acid salts (2%), whereas Al salts (2%), Fe salts (1%) and tannic acid salts (2%), have produced successful results as post-chemical mordants. Overall, it was discovered that pomegranate extract (2%), used as a post-bio-mordant, and salt of Fe (1.5%), used as a post-chemical mordant, both exhibit exceptional colour strength. Ultrasonic treatment, a procedure that is harmless for the environment, has only served to increase the colour strength of dye on wool fabric, and the addition of bio-mordants has made the process more sustainable.
Keywords: Amba Haldi; mordant; natural dye; sustainability; ultrasonic.