Donnan Approach to Equilibrium Sorption: Interactions of Cationic Dyes with Acrylic Fibers

The equilibrium sorption of ten cationic dyes by porous and regular acrylic fibers has been investigated. The data have been interpreted by a simple Donnan approach, based on the assumption that there are two different types of acidic groups in these fibers. The ionic distribution coefficients K D for the dyes and the fibers were calculated. These coefficients provide an indirect measure of the “affinity” of the dyes for the fibers. The values of K D have been discussed in relation to the structures of the dyes and fibers, and in relation to the effects of salts, pH, and temperature.