The sorption of electrolytes by a cation-exchange resin membrane

The sorption of hydrochloric acid, sodium chloride, sodium bromide, magnesium chloride and magnesium sulphate from aqueous solutions at nine concentrations up to 1m by a disk of the cation exchanger Zeo-Karb 315 has been measured at 25° C. Determinations at 15 and 35° C show that the temperature coefficient is very small. The volume of the disk in contact with these solutions has also been measured. The results are used to obtain the activity coefficients of the electrolytes in the resin phase. The significance of these is examined in terms of the Katchalsky & Lifson theory of polyelectrolyte solutions which seems more applicable than the ion fixation theory.