MOFs-derived magnetic chestnut shell-like hollow sphere NiO/Ni@C composites and their removal performance for arsenic(V)

Well-ordered, hollow, magnetic, high specific surface area composites have recently received enormous attention for the treatment of pollutants containing heavy metal ions. Herein, a serious of magnetic chestnut shell-like hollow sphere structure composites (NiO_x/Ni@C) were derived via pyrolyzing a MOF containing nickel as self-sacrificed template and served as adsorbent materials for arsenic(V) (As(V)) removal from aqueous solutions. The experimental results indicated that the adsorption capacity of NiO/Ni@C400 towards As(V) (454.94 mg/g) was higher than that of Ni@C600 (342.77 mg/g), Ni@C500 (290.89 mg/g), NiO@C300 (210.40 mg/g), and Ni-MOFs (133.93 mg/g), which could be ascribed to NiO/Ni@C400-rich oxygen-containing functional groups and high specific surface area. The NiO/Ni@C400 had a high magnetization intensity and could be easily separated under external magnetic field. In addition, the NiO/Ni@C400 had an excellent As(V) removal performance over a broad pH range from 1 to 10. The significant adsorption capacity and reusability of the NiO/Ni@C400 coupled with the easy separation property indicated that the NiO/Ni@C400 has great potential in As(V) purification industry.