Synthesis of 3D porous ferromagnetic NiFe2O4 and using as novel adsorbent to treat wastewater

Three dimensions (3D) porous NiFe2O4 is synthesized by a sol-gel method using egg white. The obtained NiFe2O4 shows both good ferromagnetic properties and high adsorption capacity. The porous NiFe2O4 shows good adsorption properties for organic dyes (Methylene Blue (138.50 mg/g), Fuchsine Red (14.61 mg/g), Methyl Violet (19.06 mg/g)) and heavy metal ions (Cu (II) (55.83 mg/g), Cr (VI) (36.95 mg/g) and Ni (II) (37.02 mg/g)) due to its 3D interconnected porous structure. The maximum adsorption of Methylene Blue (MB) fit the pseudo-second-order model and Langmuir isotherm equation well. More interestingly, the ferromagnetic NiFe2O4 can be separated under a magnetic field conveniently and keeps high removal efficiency (>97%) during seven reusable cycles. These results suggest that the porous NiFe2O4 is a promising favorable and reusable adsorbent. (C) 2011 Elsevier Inc. All rights reserved.