Wax‐Casted Macroporous Polyamidoxime Hydrogel Particles Encapsulated in Alginate‐Polyacrylic Acid Beads for Highly Efficient Uranium Capture from Seawater

Abstract Extracting uranium from the ocean is considered a promising solution for meeting nuclear fuel consumption. To date, porous adsorbents fabricated with polyamidoxime (PAO), particularly macroporous PAO hydrogels, have demonstrated exceptional potential for uranium capture from natural seawater. Herein, a novel macroporous PAO hydrogel is developed via a well‐designed wax‐casting method. The developed wax‐casted macroporous PAO (WMPAO) hydrogel particles are subsequently encapsulated in alginate‐polyacrylic acid (A‐PAA) beads. The obtained A‐PAA@WMPAO beads exhibit a high q_max of 687.4 mg‐U/g‐Ads. and show a good adsorption capacity of 8.23 mg g⁻¹ toward uranium in simulated seawater. Additionally, A‐PAA@WMPAO shows good reusability with a 31.2% reduction in uranium adsorption capacity after five consecutive adsorption‐desorption cycles. Furthermore, A‐PAA@WMPAO displays satisfactory extraction efficiencies of 95.9–99.5% for U‐spiked coastal seawater after 10 days of adsorption, achieving adsorption capacities ranging from 207.5 to 3963.2 µg g⁻¹. Particularly, with the utilization of 4 mg of A‐PAA@WMPAO beads, a high adsorption capacity of 4.79 mg g⁻¹ for uranium from 10 L of coastal seawater within 15 days is achieved. These obtained results comprehensively demonstrate the significant potential of the fabricated A‐PAA@WMPAO beads for uranium capture from natural seawater.