Efficient capture of Sr2+ from acidic aqueous solution by an 18-crown-6-ether-based metal organic framework.

The capture of highly radiotoxic ⁹⁰Sr from an acidic waste solution during used fuel reprocessing and environmental remediation in a nuclear accident is desirable and challenging. Herein, we show a metal organic framework material (SNU-200) functionalized with an 18-crown-6-ether, whose specific binding site with an excellent affinity toward strontium leads to excellent Sr²⁺ adsorption capability under acidic conditions. This material exhibits a high adsorption capacity (44.37 mg g⁻¹ at pH = 3), remarkable affinity (K_d = 3.63 × 10⁴ mL g⁻¹) and ultrahigh selectivity in the presence of interfering coexisting ions such as Na⁺, K⁺, Cs⁺, Mg²⁺, and Ca²⁺. [ABSTRACT FROM AUTHOR]