Amino modified nanofibers anchored to Prussian blue nanoparticles selectively remove Cs⁺ from water

To improve the selective separation performance of silica nanofibers (SiO₂ NFs) for cesium ions (Cs⁺) and overcome the defects of Prussian blue nanoparticles (PB NPs), PB/SiO₂-NH₂ NFs were prepared to remove Cs⁺ from water. Among them, 3-aminopropyltriethoxysilane (APTES) underwent an alkylation reaction with SiO₂, resulting in the formation of a dense Si-O-Si network structure that decorated the surface of SiO₂ NFs. Meanwhile, the amino functional groups in APTES combined with Fe³⁺ and then reacted with Fe²⁺ to form PB NPs, which anchored firmly on the aminoated SiO₂ NFs surface. In our experiment, the maximum adsorption capacity of PB/SiO₂-NH₂ NFs was 111.38 mg/g, which was 31.5 mg/g higher than that of SiO₂ NFs. At the same time, after the fifth cycle, the removal rate of Cs⁺ by PB/SiO₂-NH₂ NFs adsorbent was 75.36% ± 3.69%. In addition, the adsorption isotherms and adsorption kinetics of PB/SiO₂-NH₂ NFs were combined with the Freundlich model and the quasi-two-stage fitting model, respectively. Further mechanism analysis showed that the bond between PB/SiO₂-NH₂ NFs and Cs⁺ was mainly a synergistic action of ion exchange, electrostatic adsorption and membrane separation.