Using Eco-friendly Ultrasound Waves for High-Performance Cotton Dyeing with Direct Dyes

Direct dyes are the most widely used dyes for cotton fabric, but their drawback includes low washing wet fastness, alkali demand, and time and energy demand. This study treated cotton fabrics with ultrasound at powers from 0-250 watts for periods from zero to 60 min. Globar solution in concentrations ranging from 0-30g/l was used as a treatment medium. The samples dyed at room temperature (25oC) without salt after being exposed to ultrasound energy for 30 min had shown comparable results to the conventionally dyed pieces that were treated with 30g/l Globar salt for 30 min at 90oC. Moreover, the results showed some enhancements in the fastness of washing, rubbing, and light, as well as CIE color components ‘L' brightness, 'a' red-green, and 'b' yellow-blue components. The results also showed that the samples dyed with ultrasound acquired more color than the normal dyeing method, where the color change ( E) was 119 and 102, respectively. More over the dyeing at room temperature and for a much shorter time when it compared to the conventional technique.