Eco‐friendly dyeing of cotton using waste‐derived natural dyes and mordants

Abstract

AbstractBecause of the environmental burden of synthetic dyes, there has been a revival in practising natural dyeing globally. Natural dyeing uses metallic mordants for improving the dye's fastness properties. However, metallic mordants are also toxic. Herein, both the dyes and mordants were extracted from plant waste using water as a green solvent. The extracted dyes were then applied to the cotton fabric using a natural mordant. The dyed fabric samples were characterised for colour yield, fastness properties, ultraviolet protection and antibacterial activity. For the intended purpose, the wastes of sugarcane bagasse, wheat bran and rice husk were used for dye and mordant extraction. It was found that by increasing the extraction temperature from 30 to 60°C, the dye yield increased. From the K/S values, it was observed that premordanting gave better colour strength than post‐mordanting or meta‐mordanting. The overall ratings for washing and crocking were 3‐4 and 4‐5, respectively. No significant antibacterial activity was observed in the dyed samples. However, excellent ultraviolet protection was observed.