Some Remarks on the Donnan Approach to the Equilibrium Sorption of Cationic Dyes by Acrylic Fibres

Recent developments in the theoretical study of the dyeing of acrylic fibres with cationic dyes are reported. By using a simple Donnan approach and by assuming that the acrylic fibres contain strongly (K1) and weakly (K2) acidic groups, it has proved to be possible to determine the values of the distribution coefficients for the inorganic ions and the values of the dissociation constants of the acidic groups, which are not otherwise directly measurable. The distribution coefficients of the cationic dyes were then determined, based on experimental sorption measurements at different sodium concentrations and at different pH values