Efficient As(V) Removal by Recyclable Composite Nickel–Iron Oxide (NiFe2O4) Derived from NiFe Layered Double Hydroxides In situ Growing on Nickel Foam

A recyclable NiFe2O4 was synthesized and applied to the removal of As(V) from arsenic-contaminated solutions by calcining Ni/Fe layered double hydroxides (LDHs) through in situ growing on nickel foam (NF). The NiFe-LDHs/NF and NiFe2O4/NF exhibited typical hierarchically porous platelet-like structures. The adsorption kinetics, isotherms, and adsorption mechanism of As(V) on NiFe2O4/NF were studied in detail. The thermodynamic parameters of the adsorption process were calculated, and the regeneration ability and stability of NiFe2O4/NF were investigated. The positive ΔH value (6.36 kJ mol−1) and negative ΔG value (< − 25.8 kJ mol−1) confirm that the As(V) adsorption on the NiFe2O4/NF is an endothermic and spontaneous process. The adsorption mechanism can be interpreted as the surface complexation between As(V) and NiFe2O4/NF. After ten adsorption/desorption cycles, the NiFe2O4/NF still exhibits excellent adsorption performances. The stability experiments showed that no Fe leaching was detected and the Ni2+ leaching concentration was about 7 μg L−1, which was much lower than the Chinese drinking water standard (20 μg L−1), indicating that NiFe2O4/NF is a potential adsorbent for As(V)-contaminated drinking water treatment.