Selective separation of ¹⁶⁹Yb from proton-irradiated Tm₂O₃ targets using phosphonate-functionalized hybrid sorbents

The phosphonate-functionalized hybrid sorbent SG85-TTHMP was evaluated for its potential in the selective recovery of ¹⁶⁹Yb from irradiated Tm₂O₃ targets, with a focus on improving separation efficiency using complexing agents and tailored elution strategies. Batch experiments conducted under equimolar conditions of Tm³⁺ and Yb³⁺ at pH 3 yielded a modest Yb/Tm separation factor of 2.1-2.3. Post-loading elution with complexing agents facilitated the removal of excess Tm³⁺, and subsequent nitric acid stripping produced a more Yb-enriched solution fraction. This enrichment was further confirmed through fixed-bed column experiments with a solution derived from irradiated Tm₂O₃ targets of ¹⁶⁹Tm(p,n)¹⁶⁹Yb reaction, employing a loading-elution-stripping sequence that consistently yielded ¹⁶⁹Yb-enriched fractions. Tailored elution prior to acid stripping proved effective in enhancing overall enrichment performance. Combined with SG85-TTHMP's operational simplicity and environmental compatibility, these results support its potential utility in selective lanthanide separation for radiochemical applications.