Desorption and transfer processes in different classes of dyes

We report an analytical approach to study dye desorption and transfer processes in aqueous environment. The study was conducted simulating standard laundry washes using two different donor textiles, a polyester textile dyed with Disperse Blue 79 and a cotton textile dyed with Reactive Red 239, and two acceptor textiles, undyed cotton and polyester, respectively. Dye bleeding/solubilization from a donor textile to the solution was investigated through UV–visible absorbance analysis, while the dye absorption onto acceptor textile was quantified by UV–visible reflectance analysis. Dye desorption and transfer processes were investigated in water and surfactant solutions at different concentrations. A desorption and transfer model for the two classes of dyes was hypothesized by performing kinetic experiments. The results show that both processes depend on the presence of surfactants for the disperse dye. Conversely, the presence of surfactants has little effect on the reactive dye. Finally, the presence of an acceptor polyester significantly increases the bleeding of the disperse dye, while the presence of an acceptor textiles less influences the total release of the reactive dye.