Kinetic Studies of Adsorption of Madder on Wool Using Various Models

In this research, the kinetics of adsorption of madder on scoured wool and mordanted wool with aluminum sulfate was studied. First the madder solution was prepared and the main compounds, alizarin, purpurin and quinizarin (1, 4 dihydroxyanthraquinone) of madder were identified by high pressure liquid chromatography (HPLC). The values of CIELAB of samples dyed with madder at different temperatures and times were measured and the results confirmed that the adsorption of madder on wool is an exothermic process. The kinetic study of adsorption of madder on scoured wool and mordanted wool fiber was fitted by pseudo first order, pseudo second order, Elovich and intra-particle diffusion models at different temperatures. The results show that the kinetic study of adsorption of madder on scoured wool and mordanted fiber was fitted by the pseudo second order model. The activation energy and adsorption kinetic of the dyes extracted from madder on scoured wool and mordanted wool were also determined by the pseudo second order model. The results indicated that increase in temperature leads to a decrease in dye adsorption on both scoured and mordanted wool fibers. The HPLC analysis of dye effluent for scoured wool confirms that decrease in dyeing temperature leads to a decrease in remaining dye compounds in the effluent.