Advances in the Efficient Removal of the Key Radioactive Nuclide 90Sr Using Crystalline Ion-Exchange Materials: A Review

Nuclear energy, a rapidly advancing clean energy source, generates significant amounts of radioactive waste, including radioactive nuclides such as cesium (Cs+), strontium (Sr2+), and uranyl (UO22+). Among these, Sr2+ is particularly concerning due to its long half-life, high mobility in aqueous environments, and its toxic effects on both human health and ecosystems. Its radioactive decay produces beta particles, posing significant environmental and public health risks, especially in the context of nuclear waste disposal. Recently, ion exchange has emerged as one of the most effective methodologies to deal with this challenge. Consequently, ion-exchange materials have become a hot topic in contemporary research. This review summarizes the latest advancements in the removal of critical radioactive ions, particularly Sr2+, using ion-exchange materials. It provides a comprehensive overview of the structures and properties of various ion-exchange materials, explaining their ion-exchange characteristics and exploring the complex relationship between structure and performance. Key considerations discussed include identifying cations that are most amenable to exchange within interlayer channels, evaluating the impact of channel dimensions on material efficiency, and strategies to enhance the ion-exchange capabilities of intercalation compounds. These factors are essential for achieving high selectivity and rapid adsorption kinetics in ion-exchange processes for Sr2+.