SIMULTANEOUS REDUCTION OF HEXAVALENT CHROMIUM AND DEGRADATION OF BISPHENOL A INDUCED BY THE PHOTOLYSIS OF FERRIC-OXALATE COMPLEXES

摘要

Simultaneous photo-processing of hexavalent chromium (Cr(Ⅵ)) and bisphenol A (BPA) by a Fe(Ⅲ)-oxalate complex system was investigated utilizing a metal halide lamp as the primary light source, and mixed wastewater containing Cr(Ⅵ) and BPA as model pollutants. The effects of light source, initial pH and initial concentrations of each reactant were explored. The results showed that Cr(Ⅵ) and BPA could be simultaneously processed by the Fe(Ⅲ)-oxalate complex system with irradiation of visible light. The efficiency of Cr(Ⅵ) reduction could reach 98.9% after 10-min irradiation, and that of BPA degradation was 79.9% after 80-min irradiation under the conditions of initial concentration of 10.0 μmol·L~(-1) BPA, 30.0 μmol·L~(-1) Cr(Ⅵ), 5.0 μmol·L~(-1) Fe(Ⅲ), 200 μmol·L~(-1) oxalate, and initial pH 3.0. The average rate of Cr(Ⅵ) reduction was 5.6 times that of BPA degradation within the first 10 min of irradiation. The optimal processing pH was 3.0. The increase of the initial concentrations of Fe(Ⅲ), oxalate and BPA could increase the processing rates of Cr(Ⅵ) and BPA. Fe(Ⅲ) initial concentration significantly affected the reduction of Cr(Ⅵ) and the photodegradation of BPA.