Spectroscopic Investigations of the Oxidative Polymerization of Hydroquinone in the Presence of Hexavalent Chromium

Figure 5

Cr K-edge XANES spectra (dashed lines) and the results of linear combination fitting (solid lines) for the precipitates collected from the reactive products of 105 mg L⁻¹ Cr(VI) with 200 or 400 mg L⁻¹ H₂Q at pH 3.0 and 25°C for 75 min and 24 h. The spectrum of the precipitates obtained from the 1 d (pH 1) sample was also shown. The spectra of the reference materials of K₂Cr₂O₇, Cr(OH)₃·nH₂O, Cr-acetate, Cr(NO₃)₃·9H₂O, and Cr(III)-HA were used for calculation during linear combination fitting.