The effect of polyanion on the diffusion of sulfonated chromophore into cellulose membranes

Abstract

The effect of polyanion on the transport of sulfonated chromophore (C.I. Direct Yellow 12) from aqueous solution into cellulose membranes has been studied at 25°C. The diffusion of the chromophore into the cellulose membrane was analyzed on the basis of a parallel transport mechanism of surface and pore diffusion as developed in our previous paper, revealing that the diffusion was controlled by surface diffusion rather than by pore diffusion. Interestingly, the concentration of polyanions influenced the adsorption equilibrium of the sulfonated chromophore into the cellulose membrane but had no effect on the diffusion coefficient of the chromophore. The diffusion coefficients of the chromophore obtained in the presence of the polyelectrolyte agreed with those obtained in the presence of a simple inorganic electrolyte.