Abstract:In this study,high activity ferrous hydroxy complex (FHC) was prepared by controlling the special reaction conditions,and reductive transformation of azo dyes was investigated by employing reactive black 5 as model pollutant.The influencing factors of reduction decolorization of reactive black (RB5) by FHC,including ferrous morphology,dosage of FHC,pH,dissolved oxygen and so on were studied.The results show that the structural state of ferrous iron has a strong reductive activity,when the dosage of ferrous iron is 89.6 mg?L-1 and initial concentration of dye is 100 mg?L-1 ,80% of RB5 disappears within 10 min; pH has an important effect on the reduction of ferrous iron with optimum pH value range of 8 to 10.The experiment studies demonstrate that reductive reaction with FHC is the most important mechanism resulting in decolorization of azo dye,rather than traditional coagulation.The chromogenic groups of azo in the dye structure become the amino groups,so the aniline compounds are the main final products.The research suggests a new mechanism on the promotion of dye decolorization by ferrous iron,improving biodegradability of wastewater,which lays a theoretical basis for the technology development
