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ZIF-8, a metal–organic framework that has significant benefits such as a substantial specific surface area, abundant active sites, and high porosity, has extensive application in environmental remediation. However, ZIF-8 is powdery and easily agglomerated, making it difficult to separate ZIF-8 from aqueous solutions and thus limiting its practical application in wastewater treatment. In this work, sodium alginate was chosen as a gel matrix, and CaCl2 as a cross-linking agent to form a calcium cross-linked MOF gel material (ZIF-8/SA). The batch adsorption investigations demonstrated that the saturated adsorption capacities of ZIF-8/SA in single Mn2+ pollution solution and Mn–Cu–Cd composite pollution solution are 179.86 mg g−1 and 101.86 mg g−1, respectively. Specifically, the adsorption of Mn2+ followed the Langmuir model and exhibited monomolecular layer adsorption. Furthermore, the adsorption of Cu2+ and Cd2+ followed the quasi-first-order kinetic model, which is primarily physical adsorption. The adsorption order of ZIF-8/SA for contaminants in the adsorption process is as follows: Cu2+ > Cd2+ > Mn2+. The SEM-EDS, FT-IR, and XPS studies revealed that the adsorption mechanism of ZIF-8/SA mostly involves ion exchange, coordination of carboxyl/hydroxyl/amino groups, and electrostatic attraction. To summarize, the experimental findings of this study demonstrate that the synthetic ZIF-8/SA hydrogel has promising applications for practical pollution treatment. [ABSTRACT FROM AUTHOR]

High mineralization activity is a crucial requirement in bone tissue engineering. In this study, a novel calcium citrate compounded amorphous calcium phosphate (CAP)/polyurethanes (PUs) composite porous 3D scaffold was developed by in situ polymerization via gas foaming method. The physical and chemical properties were characterized and discussed. The results showed that the HDI can react mildly with hydroxyl (–OH) groups of PEG, while gas foaming action was caused by the release of CO2 occurred in the reactive process, resulting in a uniform porous structure of PUs scaffold. The porosities of the synthetic PEGCAP porous scaffolds are all above 70% with high interconnectivity, while the porosity decreased 27% with increasing CAP to 40%. Furthermore, the mechanical properties of porous scaffolds enhanced about 16 times after addition of CAP. After immersing in simulated body fluid (SBF), the surface structure of the porous scaffold kept stable, and surface deposits formed, indicating that the porous scaffold has good mineralization activity. In addition, the in vitro cells proliferation assay confirms the excellent bioactivity of PEGCAP porous scaffolds. [ABSTRACT FROM AUTHOR]

Na-ion batteries (SIBs) are emerging as a promising alternative to Li-ion batteries for large-scale energy storage in light of abundant Na resources and their low cost. Development of appropriate electrode materials that can conquer some critical issues such as low theoretical storage capacity and sluggish redox kinetics resulting from the larger radius of Na is urgently needed for their practical applications. In this work, boron-rich 2D BxN (x = 2, 3, and 5) has been explored as promising anode materials for high-performance SIBs based on density functional theory calculations. BxN electrodes exhibit moderate affinity toward Na-ions with adsorption energies of −0.41 to −1.21 eV, which allows stable Na-ion intercalation without the formation of metal dendrites. Moreover, both B3N and B5N deliver low diffusion barriers (0.28 and 0.08 eV) for Na-ion migration, guaranteeing a high charging/discharging rate. More importantly, these BxN anodes exhibit not only a remarkably high theoretical capacity of 1129–1313 mA h g−1 but also a low open-circuit voltage (0.45–0.87 V), which is important to achieve high energy density. AIMD simulations have confirmed the excellent cyclability of BxN electrodes during reversible lithiation/delithiation. These results suggested that the BxN electrode could be used as a new lightweight SIB anode with high capacity, cyclability, and desired rate performance. [ABSTRACT FROM AUTHOR]