Remediation of Cr(VI) by biogenic magnetic nanoparticles: An x-ray magnetic circular dichroism study

Biologically synthesized magnetite (Fe(3)O(4)) nanoparticles are studied using x-ray absorption and x-ray magnetic circular dichroism following exposure to hexavalent Cr solution. By examining their magnetic state, Cr cations are shown to exist in trivalent form on octahedral sites within the magnetite spinel surface. The possibility of reducing toxic Cr(VI) into a stable, nontoxic form, such as a Cr(3+)-spinel layer, makes biogenic magnetite nanoparticles an attractive candidate for Cr remediation. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3249578]