Mixture diffusion of sulfonated dyes into cellulose membrane: IV. Effects of complex formation between a couple of dyes

Mixture diffusion of a couple of dyes (C. I. Direct Blue 1 and C. I. Direct Red 81) which have tendency to form a 1:1 complex between the dyes in aqueous solution was studied at 55 °C. Adsorption isotherms, uptake curves and concentration–distance profiles were measured experimentally. It was examined whether the diffusion of the dyes could be analyzed based on the parallel diffusion theory of surface and pore diffusion, in addition, how the complex formation between two kinds of dye molecules affect the diffusion behavior of the dyes.