Prussian blue-immobilized polyacrylonitrile/tannic acid nanofibers for the rapid and selective removal of radioactive cesium

• Prussian blue-immobilized polyacrylonitrile/tannic acid nanofibers were fabricated • The results revealed fast Cs adsorption kinetics, with 98.72% removal of Cs within 10 min. • The Cs adsorption mechanism involves chemisorption on the heterogeneous surface of the nanofibers • This material shows excellent Cs selectivity in various pH ranges and even under salt conditions. • Our PB-immobilized nanofibers exhibited excellent removal of 137 Cs from seawater With the renewed interest in nuclear power, the efficient and selective removal of cesium from radioactive wastewater has emerged as a critical challenge, driven by concerns about environmental safety and public health. In this study, nanofibers (NFs) functionalized with Prussian blue (PB) were developed to capture radioactive cesium effectively from contaminated water. The NFs were produced by electrospinning a solution containing polyacrylonitrile (PAN) and tannic acid (TA), followed by PB formation through coordination between TA and Fe³⁺ ions. The size of the PB agglomerates and PB content in the NFs were optimized by varying the number of times the NFs were sequentially reacted with Fe 3+ and ferrocyanide, which are precursors of PB. Cs + adsorption on the PB-immobilized NFs was best described by the pseudo-second-order kinetic model and the Freundlich isotherm, suggesting that a chemisorption process occurred on a heterogeneous surface. The PB-immobilized NFs showed high selectivity toward Cs + , with distribution coefficients on the order of 10 4 – 10 5 mL/g, even in the presence of competing cations such as K + , Na + , and Ca 2+ . More importantly, our PB-immobilized NFs effectively removed 137 Cs + from groundwater and seawater, demonstrating excellent potential for the selective removal of 137 Cs + from various radioactive wastewaters.