Performance and mechanism of uranium (VI) removal from aqueous solution by zero-valent nickel@hollow glass particles (ZVNi@HGP)

The zero-valent nickel@ hollow glass particles (ZVNi@HGP) were prepared by liquid phase reduction method and characterized with SEM, XRD and XPS. The morphological structure analysis revealed that HGP can effectively mitigate the agglomeration of ZVNi particles and improve the activity of the material. The removal efficiency of U(VI) by the ZVNi@HGP was examined through a series of single-factor experiments. The results showed that ZVNi@HGP had a good removal efficiency for U(VI), with the removal rate reached up to 98.15% at uranium concentration of 10 mg/l, solid-liquid ratio of 0.15 g L-1 and pH = 4.0. The adsorption isotherm model showed a maximum adsorption capacity of 423.33 mg/g for U(VI). The adsorption of U(VI) by ZVNi@HGP follows a pseudo-second-order kinetic model, which indicates that the adsorption of U(VI) by ZVNi@HGP is predominantly a chemical process. Thermodynamics shows that the removal of uranium by ZVNi@HGP is spontaneous. The results of the study showed that HGP could reduce the agglomeration of ZVNi, so the removal ability of ZVNi@HGP was superior to that of ZVNi.