Oxidation of green rust suspensions containing different chromium ion species

The oxidation of hydrosulphate green rust (GR2(SO42−)) suspension containing different chromium ion species was investigated by X-ray diffraction, X-ray absorption spectroscopy and transmission electron microscopy. The pH, oxidation-reduction potential and amount of dissolved oxygen in aqueous solutions were measured during the reactions. The results show that the addition of Cr(III)2(SO4)3 solution suppresses the transformation of GR2(SO42−) into iron oxyhydroxides and oxides in aqueous solution, while the addition of Na2Cr(VI)O4 solution promotes the transformation of GR2(SO42−) in which Cr(VI) is reduced to Cr(III); α-FeOOH particles were refined by the addition of the chromium ions.