Sodium nonatitanate (Na4Ti9O20), which is a highly selective inorganic ion exchanger for strontium, is regenerable, is radiation resistant, and has a high cation exchange capacity. This paper summarizes the test results with a variety of simulants for tank waste and groundwater streams that demonstrate the potential of this unique material. Sodium nonatitanate is most effective in an alkaline environment and tolerates high concentrations of competing ions. It retains substantial effectiveness in the presence of organic complexants. Sodium nonatitanate is available either in powder or pellet form: both materials are stable in an alkaline tank waste environment.