The mechanisms of reactive blue photodegradation by iron(Ⅲ)/H_2O_2/HA systems

摘要

The mechanisms of reactive blue (RB) photodegradation under simulated solar irradiation in different systems has been studied. The results show that [H2O2](0) was the determining factor for light/H2O2/Fe(III) system in decomposing RB. The pH value has a significant effect on H2O2/Fe(III) system. At pH values of 3, 4, 5 and 6, the removal efficiencies of RB were 61%, 49%, 43% and 39%, respectively. Further, the role of humic acid (HA) was examined. The pH range of H2O2/Fe(III) system was extended by the existence of the HA. The mechanisms of RB photodegradation by H2O2/Fe(III)/HA systems included 4 pathways: the hydroxyl radical ((OH)-O-center dot) produced from irradiated H2O2/Fe(III) system, the (OH)-O-center dot produced from irradiated H2O2/Fe(III)/HA system, the adsorption by Fe(III)-HA complexes and the other reactive species produced from light/H2O2/Fe(III)/HA system. Overall, the (OH)-O-center dot leading to RB degradation was the major pathway and accounted for about 72% of the total RB degradation.