Novel metal-organic framework hydrogel for enhanced selective removal of uranyl ions from nuclear wastewater

The efficient removal of uranium (U(Ⅵ)) from nuclear wastewater presents a significant challenge due to the high concentrations of uranium and various interfering ions. In this study, we developed and used metal-organic framework hydrogel (MOFH) as a highly efficient adsorbent for uranium removal. The MOFH, synthesized with ferrocyanides and functional groups (Fe(Ⅱ)-CN-Fe(Ⅲ), OH, -COOH, and -NH₂), exhibited good chemical stability, large separation capacity, and high selectivity. The hydrogel's three-dimensional network, crosslinked with chitosan and alginic acid, significantly enhanced uranium removal. Even in the presence of high concentrations of coexisting cations and organic matter, the MOFH maintained a high removal rate (>95%) and distribution coefficient (K_d), and thus demonstrated strong resistance to interference from coexisting ions and showed great applicability in complex wastewater. The study also explored the MOFH's potential in treating uranium-contaminated wastewater from a smelting mine, showing effective uranium removal with minimal impact on other wastewater components. This research contributes to the development of novel adsorption materials and the understanding of their removal mechanisms, offering a comprehensive solution for the efficient removal of uranium from aqueous systems.