Effects of Polyelectrolytes on the Diffusion of Low Molecular Weight Ionic Solutes

Abstract

ABSTRACT:The diffusion of sodium sulphate in dilute solutions of carboxymethylcellulose sodium salt (CMC) was studied using the porous frit technique. It was found that at relatively low CMC concentrations, the diffusivity of sodium sulphate (D) is higher than that in water (D0); with increasing CMC concentration, the diffusivity of sodium sulphate decreases gradually and reaches a value lower than that in water. The relation between salt diffusivity ratio (D/D 0 ) and CMC concentration (C) is represented by the equation: D/D0 =a-bC. The effect of temperature on the diffusivity of sodium sulphate in CMC solutions was found to obey the Arrhenius equation with an activation energy of 2600 cal mo1-1 .