Facile Synthesis of Nanolayered Manganese Oxide for the Efficient and Selective Removal of Strontium(II) from Nuclear Wastewater

Abstract Efficient and selective removal of radioactive 90 Strontium ( 90 Sr) from nuclear wastewater is a sustainable strategy for nuclear energy development and environmental protection due to its long half‐life and high biochemical toxicity. Herein, a novel nanolayered manganese oxide material (Na 0.7 MnO 2.05 , Na‐NLMO) is proposed and its application for Sr(II) capture in both simulated waste liquid and real natural water systems. Na‐NLMO is tailored for Sr(II) adsorption through a simple and rapid solid‐phase reaction, which has good chemical stability and a strong affinity for Sr(II) across the pH range of 1 to 8. The maximum adsorption capacity is 145.21 mg g −1 taking advantage of the solid‐liquid ratio of 0.67 g L −1 . The loaded Sr(II) is almost quantitatively recovered by dilute hydrochloric acid solution. Even after 4 adsorption‐desorption cycles, it could still effectively adsorb more than 99.9% of Sr(II). Furthermore, the adsorption is unaffected by the excess presence of sodium(I), potassium(I), magnesium(II), and calcium(II). In real‐world media such as tap water and river water, its distribution coefficients are 5.2 × 10 5 and 5.6 × 10 5 mL g −1 , respectively. More importantly, the distribution coefficient toward 90 Sr in seawater still achieved 2.5 × 10 3 mL g −1 . The adsorption mechanism of electrostatic interaction and ion exchange is revealed by combining experimental results and spectroscopic analysis, such as Transmission Electron Microscope and X‐ray diffraction. The results are expected to provide new insights into the development of innovative and practical technologies for the treatment and disposal of secondary nuclear waste.