Adsorption, kinetics, and thermodynamic study of dyeing the Scutellaria Orientalis L as an eco-friendly natural colourant on cotton fabric

Abstract

The adsorption isotherm, thermodynamic parameter, and kinetics study for dyeing without mordanting cotton fabric dyed with natural dye obtained from an aqueous extract of the Scutellaria Orientalis were investigated using, as optimal conditions, at pH of 5 a material to liquor ratio (MLR) of 1:100, an initial dye concentration of 1.0/l and contact time (20–90 min.). The effect of the temperature and dyeing time (from 20–90 min.) on dyeing was evaluated using three different temperatures (from 60, 80, and 90°C). Also, the adsorption isotherms have been analyzed by Langmuir and Freundlich models. It is revealed that the adsorption kinetics was found to follow the pseudo-first-order kinetic model, the obtained adsorption isotherm was found to be suitable for both Langmuir and Freunlich adsorption isotherm, and the dyeing process is exothermic. The rate of dye uptake and thermodynamic parameters have also been calculated and discussed.