Hollow Fe3O4 nanospheres covered by phosphate-modified layered double hydroxides for the removal of uranium (VI) from water and soil

Abstract

Herein, a novel nanosphere composed of a magnetic h-Fe3O4 (hollow ferroferric oxide) core and a phos-LDH (phosphate-modified layered double hydroxide) shell was synthesized. The h-Fe3O4@phos-LDH nanocomposite with rich phosphate groups and large specific surface area (93.53 m2/g) can be exploited for uranium (VI) elimination. Batch experiments were conducted to investigate the impacts of various conditions (pH, time, and temperatures) on U(VI) removal process. The maximum capacity of U(VI) adsorbed by h-Fe3O4@phos-LDH reached up to 542.6 mg/g at 298.15 K, and the adsorption isotherms were followed the Langmuir model. Thermodynamics analyses illustrated that the U(VI) adsorbed by h-Fe3O4@phos-LDH was a spontaneous and endothermic process. The characterization analysis manifested that the phosphate groups of the phos-LDH shell played a leading role in adsorption. More importantly, the removal of U(VI) from the soil by h-Fe3O4@phos-LDH with the assistance of an electromagnetic separation system was also investigated. The results indicated that h-Fe3O4@phos-LDH could remove more than 90% of U(VI) in soil. These findings demonstrated this work could be considered as a valuable research for the environment remediation.