Construction of a phosphonate-based hydrogen-bonded organic framework for efficient extraction of uranium from seawater

Extraction of uranium represents one of the valuable but challenging processes in the fields of resource recycling and environmental protection. Here, a low-cost and efficient phosphate-based hydrogen-bond organic framework (P-HOF) was designed for the adsorption of uranium with abundant phosphate groups on its surface, exhibiting superior removal performance (Q m = 1066.0 mg g −1 ) for uranium. It had high selectivity and good recyclability for U(VI) in simulated seawater, and after five adsorption-desorption cycles, the adsorption capacity of uranium decreased slightly, but it can still be maintained at more than 80 %. Impressively, P-HOF demonstrated excellent uranium removal capabilities across a wide pH range, with removal rates exceeding 70 % even under acidic conditions (pH = 1), and the P-HOF adsorbed 7.58 mg g −1 of uranium from natural seawater under 13 days. This work indicates that the phosphonate-based P-HOF could be utilized as a promising adsorbent for the effective removal of uranium from seawater.