Study of Dyeing Behavior of Nylon 6 Fibers with Acid Dyes

Sorption isotherms of two acid dyes, Blue 127 and Green 25 on nylon 6 fibers were studied at 90 and 98C, respectively. A remarkable deviation from Langmuir isotherm was obtained for both dyes. Performance of Dual-Mode sorption model which consists of Langmuir mechanism and Nernst model was tested. Dual-Mode fitting was appeared to be in good agreement with the experimental data rather than Langmuir. In addition, the sorption capacity of fiber from measuring the amino end-group content and that calculated from Langmuir isotherm was compared. The results confirmed that the adsorption is not limited only to the sitting mechanism and there are the other sites involving in the adsorption. Studying the temperature effect on Dual-Model isotherm showed the total adsorption capacity of fiber is decreased by increasing the temperature. However the most part of total sorption was still followed as Langmuir isotherm. J