“…On the other hand, removal of strontium from high ionic strength solutions dominated by sodium ions has been studied. For example, years of studies on separation and purification of strontium from high-level waste stored in underground tanks at Hanford, WA, produced successful precipitation methods (e.g., lead sulfate, ferric hydroxide, calcium carbonate), solvent extraction (e.g., using di-2-ethylhexyl phosphoric acid or novel heterocyclic compounds such as dicyclohexano-18-crown-6), and ion exchange (e.g., antimonic acid, titanates) (see Schulz and Bray 1987;Orth and Kurath 1994). More recently, Morimoto et al (2011) reported the use of magnesium vermiculite from South Africa that could not retain Sr 2+ in the presence of 3% sodium ion, but upon removal of the sodium via an upstream tetraethylammonium ion exchanger, Sr 2+ could be retained well in column experiments.…”