Simultaneous removal of radioactive cesium and strontium from seawater using a highly efficient Prussian blue-embedded alginate aerogel

Radioactive cesium (Cs-137) and strontium (Sr-90) 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 (Cs-137) and strontium (Sr-90) 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 aemgel. The Cs+ and Sr2+ adsorption behaviors on the PB-alginate aemgel 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. Cs-137 and Sr-90 removal tests in real seawater demonstrated the practical feasibility of the PB-alginate aerogel as an adsorbent.

Automated summary

A Prussian blue (PB)-immobilized alginate aerogel was fabricated for the simultaneous removal of radioactive cesium (Cs-137) and strontium (Sr-90) from seawater, demonstrating good adsorption performance and practical feasibility in real seawater. The composite showed different adsorption sites for Cs+ and Sr2+, allowing for efficient removal within 3 hours, with stronger competition observed for Sr2+ adsorption in the presence of other cations in seawater.