Ultrasound-assisted dyeing of cotton fabric with natural dye extracted from Marigold flower

The eco-sustainable natural dyes and their application are increasing due to the control of pollution, biological protection and easy application. In this study, Marigold natural dye was extracted from the flowers of the indigenous crop and applied onto cotton fabric by ultrasound-assisted dyeing method. In the first stage, the extraction of natural dye was optimized. Afterward, mercerized cotton fabric was dyed with the extracted Marigold dye. The dyed fabrics produced yellow shades onto cotton substrate. Higher colored yields of the dyed fabrics up to the value of 25 and acceptable colorfastness were achieved at optimized conditions. However, dyeing by pre-mordanting method, washing fastness was marginally improved. Comparing conventional and ultrasound dyeing methods, savings in amount of water (around 16%), thermal energy (for lesser dyeing temperature) and salt concentration (around 14%) required for ultrasound dyeing were notable. Also, representative wastewaters showed around 30% reduction in the total dissolved solids contents. Additionally, tensile strength, stiffness and surface morphology of the dyed fabrics were also assessed and found acceptable.

Automated summary

The study demonstrates that Marigold natural dye extracted using ultrasound-assisted dyeing method can produce vibrant yellow shades on cotton fabric, with higher color yields and acceptable colorfastness achieved under optimized conditions. Compared to conventional dyeing methods, ultrasound dyeing saves water, thermal energy, and salt concentration, resulting in a notable reduction in total dissolved solids contents in wastewater.