Engineering surface structure in Si-doped TiO2 microspheres for selective separation of strontium and yttrium

The radionuclide 90 Y is essential for targeted tumor radiotherapy, yet its clinical utilization relies on efficient isolation from parent 90 Sr. Bare TiO 2 exhibits low Y 3+ uptake and weak Sr/Y selectivity, restricting its practical deployment. Silicon-doped TiO 2 microspheres (Si-TiO 2 ) were fabricated via a two-step route with tuned Si doping. Multiscale characterizations verify lattice incorporation of Si 4+ , which greatly elevates the material’s specific surface area and surface hydroxyl abundance. The optimized Si-TiO 2 realizes near-quantitative Y 3+ capture over pH 3–7, delivering a maximum Sr/Y separation factor of 400 and a Y 3+ adsorption capacity of 15.21 mg/g at 298 K. Adsorption obeys the pseudo-second-order kinetics and Langmuir isotherm, corresponding to spontaneous endothermic chemisorption. The material also possesses outstanding acid-base tolerance, recyclability and dynamic column separation capability. Mechanistic analyses confirm that selective Y 3+ uptake originates from surface complexation between Y 3+ and surface Ti-OH sites. This work provides a potential inorganic adsorbent candidate for developing ⁹⁰Sr/⁹⁰Y medical generators. Download: Download high-res image (236KB) Download: Download full-size image