ABSTRACT
This chapter shows how the knowledge of ion exchange selectivity acts as a predictive tool in a real-life field situation, where there are myriad competing ions in the feed of the membrane process. According to information available in the open literature, ion exchange selectivity data have never been used as surrogate process parameters for predicting the hierarchy of permeation of ions in semipermeable membrane processes. The use of ion exchange selectivity as an indicator of relative permeability of different ions through semipermeable membranes is meaningful only if the same can be determined rapidly and reliably through easyto-perform experiments. Ion exchange selectivity can be estimated by noting the time of elution in an ion chromatogram; the higher the time of elution, the higher the ion exchange selectivity among homovalent ions. Reverse osmosis and nanofiltration have emerged as major treatment techniques in water industries.
