Abstract: The removal of cesium-137 (¹³⁷Cs) from nuclear wastewater remains crucial due to its radioactivity and high solubility in water, which pose serious risk to human health and the environment. Aiming at selective capture of Cs⁺ from wastewater, a core-shell adsorbent, Prussian blue analog@γ-alumina (PBA@Al₂O₃) pellets were synthesized using the hydrothermal-stepwise deposition method. The core-shell PBA@Al₂O₃ pellets showcased a PBA loading of 25% and demonstrated a maximum adsorption capacity of 15.65 mg·g^-1. The adsorption data was consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model. It effectively reduced bulk Cs⁺ concentrations from an initial 6.62 mg·L^-1 to 2 μg·L^-1, achieving a removal efficiency of 99.97% and distribution coefficient (K_d) of 1.265×10⁶ ml·g^-1, surpassing the performance of other PBA-based materials. The material also indicated good mechanical properties and cesium ion removal rates of 99.7% across a wide pH range (1.82 to 11.12). Furthermore, PBA@Al₂O₃ exhibited consistent removal rate of over 99% and good selectivity (SF=50—1600) towards Cs⁺ even in the presence of interfering ions such as Na⁺, K⁺, Mg²⁺, and Ca²⁺ ions. The K_d(Cs⁺) for PBA@Al₂O₃ in simulated seawater and groundwater were 9.92×10³ and 2.23×10⁴ ml·g^-1, where the removal rates reached 96.1% and 98.2%, respectively. XPS confirms that the adsorption mechanism is the ion exchange between Cs⁺ and K⁺ ions. This study underscores the significant potential of inorganic core-shell pellets adsorbents as promising agents for the selective capture of Cs⁺ from wastewater.

Key words: Adsorption, Cesium removal, Prussian blue analog, Nuclear wastewater, Core-shell

摘要： The removal of cesium-137 (¹³⁷Cs) from nuclear wastewater remains crucial due to its radioactivity and high solubility in water, which pose serious risk to human health and the environment. Aiming at selective capture of Cs⁺ from wastewater, a core-shell adsorbent, Prussian blue analog@γ-alumina (PBA@Al₂O₃) pellets were synthesized using the hydrothermal-stepwise deposition method. The core-shell PBA@Al₂O₃ pellets showcased a PBA loading of 25% and demonstrated a maximum adsorption capacity of 15.65 mg·g^-1. The adsorption data was consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model. It effectively reduced bulk Cs⁺ concentrations from an initial 6.62 mg·L^-1 to 2 μg·L^-1, achieving a removal efficiency of 99.97% and distribution coefficient (K_d) of 1.265×10⁶ ml·g^-1, surpassing the performance of other PBA-based materials. The material also indicated good mechanical properties and cesium ion removal rates of 99.7% across a wide pH range (1.82 to 11.12). Furthermore, PBA@Al₂O₃ exhibited consistent removal rate of over 99% and good selectivity (SF=50—1600) towards Cs⁺ even in the presence of interfering ions such as Na⁺, K⁺, Mg²⁺, and Ca²⁺ ions. The K_d(Cs⁺) for PBA@Al₂O₃ in simulated seawater and groundwater were 9.92×10³ and 2.23×10⁴ ml·g^-1, where the removal rates reached 96.1% and 98.2%, respectively. XPS confirms that the adsorption mechanism is the ion exchange between Cs⁺ and K⁺ ions. This study underscores the significant potential of inorganic core-shell pellets adsorbents as promising agents for the selective capture of Cs⁺ from wastewater.

关键词: Adsorption, Cesium removal, Prussian blue analog, Nuclear wastewater, Core-shell