Reduction of sodium and chloride ion content in aqueous solutions by bulk liquid membranes: a kinetic approach Original Research Article

A kinetic study of the facilitated transport of sodium and chloride ions through bulk liquid membranes containing, respectively, di(2-ethylhexyl) phosphoric acid and tri-n-octylmethyl ammonium hydroxide, as carriers, and using, respectively, hydrogen and hydroxyl ions as counter-ions in the product phase, is described. After 24 h, the ion content of the feed phase had been reduced by more than 95% in both cases, obtaining recoveries in the product phase of 81% for sodium ion and 89% for chloride. The transport kinetic was analysed by means of a kinetic model involving two consecutive irreversible first order reactions. The rate constants of the extraction and stripping reaction were experimentally determined. Model curves of time dependence for the reduced concentrations of both sodium and chloride ions in feed, membrane and product phases showed good agreement with experimental data.