The adsorption study of surfactant-dye aqueous solutions on the cellulosic materials is very important, knowing that the mixed surfactant-dye micelle can reach in the surface waters, while through adsorption the surfactants can be accumulate in soil and they can influence the normal development of the plants and live organisms. It has been studied the competitive adsorption between: biodegradable nonionic surfactants, cationic surfactants with antiseptic properties, germicides and the methylene blue, a vital dye on cotton/water interface. By UV-VIS spectrophotometric and tensiometric measurements it was determinate the form of adsorption isotherms on cotton for methylene bluemicellar surfactant aqueous solutions. The classic quantitative methods (Langmuir, Fowler-Guggenheim) that describe the surfactant adsorption on solid/liquid interface have been tested, allowing the description of the interaction type and the accumulation mode of mixed surfactant-dye micelles on cotton/water interface.
