Eco-friendly and effective dyeing of wool with anthraquinone colorants extracted from Rubia cordifolia roots: Optimization, colorimetric and fastness assay

The present study is aimed to explore the dyeing ability of anthraquinone colorants extracted from Rubia cordifolia Lin. roots. Sustainable approach for textile dyeing with a systematic protocol is followed with the effect of AlCl 3 and CaCl 2 metallic mordants. The optimization of extraction and dyeing conditions was assessed by Reflectance Spectrophotometry. The optimum extraction and dyeing conditions were found to be pH = 2, time = 45 min and temperature 90 °C and pH = 4, time = 90 min and temperature 90 °C respectively. At optimized conditions, dyeing abilities of pre-mordanted with metallic salts as anchoring agent (AlCl 3 and CaCl 2 ) were compared. Wool samples dyed with Madder root extract impart radiant red shades with or without mordants having different hue and tones with commercially acceptable colorimetric and fastness properties without sacrificing much of the resources. Effective improvement in color as well as fastness properties was observed using anchoring agents.