Chlorate transport through ion-exchange membranes

A laboratory scale chlor-alkali membrane cell was used to measure the chlor ate concentration in the outlet NaOH as a function of current density, temp erature, film thickness, brine strength and various membrane properties. Th e chlorate concentration in the NaOH increased with increasing anolyte chlo rate spiking level and temperature and decreasing current density and carbo xylate film thickness and was strongly dependent on the type of ion-exchang e membrane used. In addition, the presence or absence of sacrificial fibers in the membrane did not measurably influence the resultant chlorate concen tration. Chlorate ions were transported to the catholyte side by diffusion and electroosmotic convection and transported toward the anolyte side by mi gration. This balance between the three modes of transport dictates the chl orate concentration present in the NaOH product.