Three-Dimensional Numerical Simulation of ⁹⁰Sr/⁹⁰Y Separation by Countercurrent Electrophoresis to Produce Medical ⁹⁰Y

⁹⁰Y is used to label antibodies and treat the tumors. In a ⁹⁰Sr/⁹⁰Y generator, the decay of ⁹⁰Sr produces ⁹⁰Y. This study presented the development of a countercurrent electrophoretic separation device as a ⁹⁰Sr/⁹⁰Y generator for producing medical ⁹⁰Y. First, the complex stability constant was used to analyze the behavior of ethylenediaminetetraacetic acid (EDTA), citric acid (CIT), and ⁹⁰Sr/⁹⁰Y in different pH environments. Then, the concentration distribution in ⁹⁰Sr/⁹⁰Y separation via countercurrent electrophoresis was systematically investigated using COMSOL simulations, with specific focus on the effects of the temperature, applied voltage, and initial strontium concentration. Finally, the experimental validation further confirmed the technical feasibility of this separation method. As a result, the best simulation results indicated that the separation factor was 9.0 × 10⁸ at a temperature of 20 °C, a voltage of 1000 V, and a flow rate of 0.0001 m/s. After consideration of electro-osmotic flow, the separation factor is 9.8 × 10⁵, while the best experimental results showed that the separation factor was 8.7 × 10⁵ at 20 °C, 1000 V, and 0.0001 m/s.