Xue Song Wang and colleagues, Huaihai Institute of Technology, China, have tested magnetite nanoparticles for the removal of Ni(II) from aqueous solutions. The magnetite nanoparticles proved effective due to high surface area and reactive hydroxyl surface sites.

The crystalline nature of the magnetite structure was characterized with transmission electron microscopy and X-ray diffractometry. The surface area was determined to be 115.3 m²/g, with a particle diameter of 10 nm.

Low Ni (II) uptake was seen at pH < 4.0. At higher pH (4.0 – 6.0), uptake of over 0.06 mmol/g was seen. In NaCl solutions, Ni(II) adsorption increased with increasing ionic strength while in NaClO₄ solutions, Ni(II) adsorption exhibited little dependence on the ionic strength of the solution.

• Removal of Ni(II) from Aqueous Solutions by Nanoscale Magnetite
  X. S. Wang, J. J. Ren, H. J. Lu, L. Zhu, F. Liu, Q. Q. Zhang, J. Xie,
  Clean Soil, Air, Water, 2010.
  DOI: 10.1002/clen.201000327