Parametric studies on the performance of mixed-bed ion exchange at ultralow concentrations - 1. Multicomponent system

We experimentally evaluated the effects of multicomponent systems of divale nt cations on the performance of mixed-bed ion exchange in the concentratio n range used for ultrapure water processing. Data were collected in the bat ch and continuous column systems with Dowex Monosphere resins used commerci ally for ultrapure water applications. The presence of divalent cations in the systems affects significantly the capacity of the units to remove a uni valent cation. However, the anion exchange rate increases slightly in the m ulticomponent systems. The equilibrium and the breakthrough curves of ions, plotted as the ratio of the effluent to influent concentration versus run time or solution volume passed through the experimental column, give detail ed results about the effects of the existence of other ionic species on the fate of each ion in MBIE units. The results of the present study are expec ted to be used to develop and simulate mathematical models and to understan d the performance of mixed-bed ion exchange at ultralow concentrations.