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

Figure 1

The UV-VIS spectra of the reaction products of 105 mg L⁻¹ Cr(VI) with (a) 200 mg L⁻¹ and (b) 400 mg L⁻¹ H₂Q at pH 3.0 and 25°C for 10, 45, and 75 min and 24 h, respectively. 1 d (pH 1) indicated that the sample was obtained by mixing 200/400 mg L⁻¹ H₂Q and 105 mg L⁻¹ Cr(VI) at pH 3.0 for 24 h, followed by the acidification treatment at pH 1.0 for 1 d. The insert in (a) indicated that the absorption peak of at 350 nm was shifted to at 370 nm with an increase in pH.

(a) 105 mg L⁻¹ Cr(VI) + 200 mg L⁻¹ H₂Q

(b) 105 mg L⁻¹ Cr(VI) + 400 mg L⁻¹ H₂Q