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• TFHH-POM was developed by using amino-modified polyoxometalates embedded in covalent organic framework pores. • The covalent bond connection between TFHH and POM improves the stability of POM. • Covalent bonding and internal confined improve the mass transfer from TFHH to POM. • TFHH-POM exhibits a notably elevated photoreduction capacity of U(VI). To achieve sustainable nuclear energy and environmental protection, capturing uranium from mining wastewater is imperative. Herein, as an extraction composite of U(VI), TFHH-POM was developed by using a highly conjugated polyaromatic ether-based covalent organic framework (TFHH) as the carrier with amino-modified polyoxometalates (POM) embedded in its pores through amide bonds. The highly conjugated structure of TFHH facilitates charge transport, and in combination with the charge density contrast between POM and TFHH, along with the constraining effect of POM within TFHH channels, jointly enhances charge separation efficiency. As a result, the photoreduction efficiency of U(VI) is substantially increased. Simultaneously, the oxygen-containing groups in POM and carboxyl groups in TFHH could selectively adsorb U(VI), while Mo(V) in POM effectively reduces U(VI) to U(IV), synergistically promoting U(VI) capture. Hence, TFHH-POM exhibits remarkable U(VI) extraction efficiency through enhanced mass transfer, improved diffusion, and introduced chemical reduction. The U(VI) extraction capacity of TFHH-POM reaches 489.2 mg/g, surpassing those of POM and TFHH by 3.2 and 1.6 times, respectively. The reduced U(IV) remains stable after 30 days of storage with no reoxidation observed. Moreover, TFHH-POM demonstrates selective U(VI) capture from mining wastewater, highlighting its vast potential for environmentally sustainable uranium mining. [ABSTRACT FROM AUTHOR]

[Display omitted] • A 3D cationic covalent organic framework (TFAM-BDNP) was synthesized via Zincke reaction. • TFAM-BDNP exhibits high adsorption capacity and extremely fast exchange kinetic for ReO 4 −. • TFAM-BDNP demonstrates remarkable selectivity for ReO 4 −. • TFAM-BDNP has outstanding removal efficiency of ReO 4 − from simulated Hanford flow sample. Due to the long half-life and high environmental mobility, the selective and efficient capture of TcO 4 − from nuclear effluents is very important, but it is still very challenging. Herein, we design and synthesize a novel three-dimensional (3D) cationic covalent organic framework (TFAM-BDNP) via Zincke reaction for selective capture of TcO 4 −/ReO 4 −. TFAM-BDNP exhibits high adsorption capacity (998 mg g−1) and extremely fast exchange kinetic (60 s) for ReO 4 − (the non-radioactive alternative to TcO 4 −), attributing to the open 3D hydrophobic channels, abundant active sites, and high chemical stability. More importantly, TFAM-BDNP shows good adsorption performance for ReO 4 − in the presence of significant excess competing anions with a wide pH value range of 2 to 12. Under complex simulated Hanford flow sample, TFAM-BDNP has outstanding removal efficiency of ReO 4 −. The adsorption mechanism of ReO 4 − is mainly caused by anion exchange process. This study provides a novel adsorbent for efficient capture of TcO 4 −/ReO 4 − in complex environmental systems and exploits an effective strategy for broadening the types of 3D COFs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Indium-based MOF is synthesized for the efficient removal of iodine from both the vapor and aqueous. • In-MOF exhibits high hydrostability even in seawater for 30 days. • In-MOF shows high selectivity and adsorption capacity for I 3 -. • In-MOF shows high-efficiency removal for iodine in seawater. The highly efficient removal of radioactive iodine from nuclear accident-polluted seawater is of great significance for the purpose of environmental protection. Herein, we report an indium-based metal–organic framework, named In-MOF, for highly efficient removing iodine from seawater. In-MOF is constructed by In3+ ions coordinated with tris (4-(1H-imidazol-1-yl) phenyl) amine and exhibits high chemical stability even under seawater for 30 days. Due to the flexible one-dimensional linear structure and high-density charged imidazolium groups, In-MOF possesses a high adsorption capacity (1138 mg/g) for iodine in water. Furthermore, it exhibits high selectivity in the presence of competitive ions, due to forming the unique I-π interactions between iodine and the In-MOF. Notably, these excellent adsorption features endowed In-MOF successfully remove iodine from seawater with a high removal rate of 93.86%. These results are of fundamental importance to understanding iodine uptake and designing materials with high adsorption capacity. [ABSTRACT FROM AUTHOR]