Simultaneous removal of radioactive cesium and strontium from seawater using a highly efficient Prussian...

Radioactive cesium (¹³⁷Cs) and strontium (⁹⁰Sr) contaminants in seawater have been a serious problem since the Fukushima accident in 2011 due to their long-term health risks. For the effective and simultaneous removal of radioactive cesium (¹³⁷Cs) and strontium (⁹⁰Sr) from seawater, a Prussian blue (PB)-immobilized alginate aerogel (PB-alginate aerogel) was fabricated and its adsorption performance was evaluated. PB nanoparticles were homogeneously dispersed in the three-dimensional porous alginate aerogel matrix, which enabled facile contact with seawater. The PB-alginate aerogel exhibited Cs⁺ and Sr²⁺ adsorption capacities of 19.88 and 20.10 mg/g, respectively, without substantial interference because Cs⁺ and Sr²⁺ adsorption occurred at different adsorption sites on the composite. The Cs⁺ and Sr²⁺ adsorption onto the PB-alginate aerogel was completed within 3 h due to the highly porous morphology of the aerogel. The Cs⁺ and Sr²⁺ adsorption behaviors on the PB-alginate aerogel were systematically investigated under various conditions. Compared with Cs⁺ adsorption, Sr²⁺ adsorption onto the PB-alginate aerogel was more strongly influenced by competing cations (Na⁺, Mg²⁺, Ca²⁺, and K⁺) in seawater. ¹³⁷Cs and ⁹⁰Sr removal tests in real seawater demonstrated the practical feasibility of the PB-alginate aerogel as an adsorbent.