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90Sr, as a typical artificial radionuclide, poses a serious threat to human health and the ecological environment. The selective removal of this radionuclide from industrial nuclear waste is crucial for our environment. Here we report a novel potassium fluoroaluminate, K2[(AlF5)H2O], which was synthesized by a simple low‐temperature one‐step method. It adopts a 1D AlF6‐chain structure, which consists of exchangeable potassium ions in between the infinite chains of octahedral Al centers. As a remarkable inorganic ionic exchanger, K2[(AlF5)H2O] has a high chemical stability (resistance of pH=~3‐12) and thermal stability (≥~300 °C). It possesses an excellent adsorption selectivity (Kd=~6.1×104 mL ⋅ g−1) and a maximum adsorption capacity of qm=~120.32 mg ⋅ g−1 for Sr2+. Importantly, it still keep a very good selectivity for Sr2+ ions even in the presence of competing Na+, Mg2+ and Ca2+ aqueous solutions. K2[(AlF5)H2O] is the first example of fluoroaluminate ionic exchange materials that can capture Sr2+. This result opens up a new way to design and synthesize inorganic ionic exchangers for the selective removal of Sr2+ ions from radioactive waste water. [ABSTRACT FROM AUTHOR]

Pentavalent uranium compounds are key components of uranium's redox chemistry and play important roles in environmental transport. Despite this, well-characterized U(V) compounds are scarce primarily because of their instability with respect to disproportionation to U(IV) and U(VI). In this work, we provide an alternate route to incorporation of U(V) into a crystalline lattice where different oxidation states of uranium can be stabilized through the incorporation of secondary cations with different sizes and charges. We show that iriginite-based crystalline layers allow for systematically replacing U(VI) with U(V) through aliovalent substitution of 2+ alkaline-earth or 3+ rare-earth cations as dopant ions under high-temperature conditions, specifically Ca(U VI O 2 )W 4 O 14 and Ln(U V O 2 )W 4 O 14 (Ln=Nd, Sm, Eu, Gd, Yb). Evidence for the existence of U(V) and U(VI) is supported by single-crystal X-ray diffraction, high energy resolution X-ray absorption near edge structure, X-ray photoelectron spectroscopy, and optical absorption spectroscopy. In contrast with other reported U(V) materials, the U(V) single crystals obtained using this route are relatively large (several centimeters) and easily reproducible, and thus provide a substantial improvement in the facile synthesis and stabilization of U(V)., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Two remarkable aluminum borophosphates (AlBPOs), namely, Na 3 [Al 2 B 6 P 4 O 22 (OH) 3 ](H 2 O) 6 (denoted as ABPO1) and Na 3 [Al 2 BP 2 O 11 ](H 2 O) 0.5 (denoted as ABPO2), have been designed and prepared by low-temperature flux syntheses. The exceptional open framework structure of ABPO1 is formed by a unique microanionic network [Al 2 B 6 P 4 O 22 (OH) 3 ] n 3- , which contains three types of 8-, 12-, and 16-membered ring (MR) tunnels. Interestingly, these tunnels are featured by a type of super-nanocage as large as ∼1.753 nm × 1.753 nm × 1.753 nm, which is the first example of AlBPOs containing extra-large cages. Importantly, it was found that Na + can be partially exchanged by K + , Sr 2+ , Cd 2+ , and Ni 2+ , which means that it is a potential ionic exchanger for removing radionuclides and toxic cations. The structure of ABPO2 features a unique 2D anionic AlBPO layer composed of corner-sharing AlO 6 octahedra and AlO 4 , BO 4 , and PO 4 tetrahedra. To the best of our knowledge, this is the first example of both AlO 6 octahedra and AlO 4 tetrahedra being contained in the structure. 9-MRs can be observed along the b -axis. Herein, the syntheses and topological structures of ABPO1 and ABPO2 as well as elemental analysis, thermal stability, infrared spectroscopy, UV-vis diffuse reflectance, structural properties, and ionic exchange properties are also discussed.

90 Sr, as a typical artificial radionuclide, poses a serious threat to human health and the ecological environment. The selective removal of this radionuclide from industrial nuclear waste is crucial for our environment. Here we report a novel potassium fluoroaluminate, K 2 [(AlF 5 )H 2 O], which was synthesized by a simple low-temperature one-step method. It adopts a 1D AlF 6 -chain structure, which consists of exchangeable potassium ions in between the infinite chains of octahedral Al centers. As a remarkable inorganic ionic exchanger, K 2 [(AlF 5 )H 2 O] has a high chemical stability (resistance of pH=~3-12) and thermal stability (≥~300 °C). It possesses an excellent adsorption selectivity (K d =~6.1×10 4  mL ⋅ g -1 ) and a maximum adsorption capacity of q m =~120.32 mg ⋅ g -1 for Sr 2+ . Importantly, it still keep a very good selectivity for Sr 2+ ions even in the presence of competing Na + , Mg 2+ and Ca 2+ aqueous solutions. K 2 [(AlF 5 )H 2 O] is the first example of fluoroaluminate ionic exchange materials that can capture Sr 2+ . This result opens up a new way to design and synthesize inorganic ionic exchangers for the selective removal of Sr 2+ ions from radioactive waste water., (© 2024 Wiley-VCH GmbH.)