Efficient removal of uranium(VI) by layered double hydroxides supported nanoscale zero-valent iron: A combined experimental and spectroscopic studies.

Graphical abstract Highlight • LDH@nZVI composite was prepared via a facile and green method. • Synergistic effects improved the capture ability for U(VI) on LDH@nZVI than single-guest. • O and Fe functional groups play an important role in the immobilization process of U(VI). • Interaction mechanism between U(VI) and LDH@nZVI was adsorption and reduction. Abstract In this study, nanoscale zero-valent iron (nZVI) supported on layered double hydroxide (LDH) composite (LDH@nZVI) was prepared, characterized and applied to U(VI) scavenging in water. Removal of U(VI) as a function of pH, ionic strength, reaction time, initial concentrations of U(VI), and temperature were studied and compared with pure LDH and nZVI, the LDH@nZVI had best U(VI) removal efficiency owning to the excellent synergistic combination of LDH adsorption and nZVI reduction. XPS analysis found that surface oxygen functional groups and surface-bound Fe(II) played a critical role in U(VI) remediation. The large surface areas (334.0 m2/g), abundant functional groups (i.e., M O, C O and OH), rapid kinetics (adsorption equilibrium within 1 h) and excellent adsorption capacities (176 mg/g) indicating that LDH@nZVI can be considered as a potential material for preconcentration of U(VI) from sewage water. [ABSTRACT FROM AUTHOR]