Conjugated melamine sponge@polyamidoxime/sodium alginate@ZIF-67 core–shell hydrogels for efficient uranium extraction from simulated seawater

Developing high-performance adsorbents to achieve efficient uranium extraction from seawater is essential for the sustainable development of nuclear energy. However, conventional adsorbents are often limited by small uranium adsorption capacity, low uranium adsorption selectivity, and poor environmental stability. Herein, we develop conjugated melamine sponge@polyamidoxime/sodium alginate@ZIF-67 (MS@PAO/SA@ZIF-67) core–shell hydrogels as adsorbents for efficient uranium extraction from simulated seawater, where the PAO/SA and ZIF-67 are in-situ synthesized on MS framework. Due to unique complexation reaction of PAO and abundant adsorption sites of ZIF-67, the as-prepared MS@PAO/SA@ZIF-67 core–shell hydrogels exhibit large uranium adsorption capacity (478 mg/g) and high uranium adsorption selectivity (41.53 %). More importantly, the MS can ensure that MS@PAO/SA@ZIF-67 core–shell hydrogels with interconnected porous network and good mechanical flexibility deliver good environmental stability (high uranium adsorption capacity of 300 mg/g and desorption rate of 78 % after three cycles), which shows excellent application prospects in uranium extraction field.