Study On Treatment Of Dye Direct Blue 12B By Combined Process Usingiron-carbon Micro-Electrolysis And Fenton Oxidation

Dye wastewater is a typical kind of bio-refractory wastewater with high concentration, chroma, complicated component and low degradability, the traditional wastewater treatment technique cannot meet the needs of discharge standard. Therefore, it has far-reaching significance to find an economical and applicable technique of wastewater treatment with high efficiency and investigate its reaction mechanism for the technique of dyeing wastewater treatment.In this dissertation, one typical dyestuffs, Direct blue 2B, were chosen as research object. Experimental research has been done in degradation of simulative dyestuff wastewater with the adoption of iron-carbon micro-electrolysis and Fenton reaction in joint application. In this dissertation, there are four aspects studied: (1) The degradation characteristics and reaction conditions of Direct blue 2B were studied particularly under combined process. (2) The degradation mechanism and pathways of Direct blue 2B using iron-carbon micro-electrolysis and Fenton reaction are also discussed. (3) The technological conditions of real dyestuff wastewater treatment were discussed experimentally with combined process.(1) According to the experimental results, iron-carbon method have an obvious effect on the treatment of dye wastewater. The best treatment conditions for simulated dye wastewater are as follows: for 300mL direct blue 2B wastewater with the concentration of 8g/L, the best pH, dosage of scrap iron, ratio of Fe/C and the reaction time are 3, 10g, 1:1.0 and 120 min respectively, COD removal rate is64.5%; For each dyestuff, the percentage of decolority reached up to 80%.(2) The best conditions for simulated dye wastewater with combined treatment technology of iron-carbon micro-electrolysis and Fenton reaction are as follows: for 300mL Direct blue 2B wastewater under iron-carbon treatment process, the best pH, dosage of H2O2 and reaction time were 3, 37mmol/L and 30 min respectively, COD removal rate and percentage of decolority are 83.9% and 93.6%;(3)The degradation pathways of Direct blue 2B dye wastewater with iron-carbon micro-electrolysis and Fenton oxidative degradation in joint application have been studied by using UV, IR and HPLC-MS Spectra analysis, the results revealed the oxidative degradation rule of azo dyestuff.With strong oxidizing property, Direct blue 2B dyestuffs can be oxidized and degraded completely by formed hydroxyl radical in Fenton reaction. Regarding to Direct blue 2B dyestuff, groups with high density of electron cloud are attacked by hydroxyl radical firstly, especial for the groups nearby azobenzene lead to azo dyestuff decolour by breaking chromophore; then the groups which can be oxidated easily are attacked, such as benzene ring and naphthalene ring;...