Photocatalytic Cobalt Chloride-potassium Persulfate Method Degradation Direct Red4B Dyeing Wastewater

Dye wastewater is a typical kind of biorefractory organics wastewater with highconcentration, high colorimeter, complicated component and low degradability, thetraditional wastewater treatment technique cannot meet the needs of dischargestandard. Therefore, it has significance to develop an economical and applicabletechnique of wastewater treatment with high efficiency and investigate its reactionmechanism for the technique of dyeing wastewater treatment.In this dissertation, one typical dye, direct red4B, was chosen as searchbjct.Experimental research has been done in degradation of simulative dyestuff wastewater with the adoption the photocatalytic cobalt chloride-potassium persulfateoxidation method in joint application. In this dissertation, there are three aspectsstudied:(1).The treating processes and reaction conditions of direct red4B werein-depth studied.(2).The degradation mechanism and pathways of direct red4B usingphotocatalytic cobalt chloride-potassium persulfate oxidation method were alsodiscussed.(3).The reaction kinetics of printing and dyeing wastewater treatment wascarried on the preliminary discussion.1. According to the experimental, the photocatalytic cobalt chloride-potassiumpersulfate oxidation method has an obvious effect on the treatment of dye wastewater.The best conditions for simulated dye wastewater are as follows: for300mL directred4B wastewater, the best pH was3.0, the dosage of K2S2O4was65mmol/L, thedosage of CoCl2was0.8mmol/L and reaction time was40min, respectively.Colorand COD removal rate are95%å'Œ73%, respectively.2. The degradation pathways of direct red4B dye wastewater with photocatalyticcobalt chloride-potassium persulfate oxidation method degradation in joint applicationhave been studied by using UV, IR and GC-MS Spectra analysis.3. Using the linear regression equation, the solution for different time to do thecorrelation analysis of time, apparent kinetic model equation was deduced to meetfitting level. Reaction kinetics of degradation of direct red4B dye wastewaterresearch not only provides related experimental data and theoretical basis, but canreveal the reaction rules, improving the effect of dye wastewater treatment, reducingthe blindness in practical engineering applications.Regarding direct red4B dyestuff, photocataly cobalt chloride and potassiumpersulfate oxidation processing can be oxidized and degraded completely by formedsulfate radical and hydroxyl radical, with high density of electron cloud are attackedby sulfate radical and hydroxyl radical firstly, especial for the groups nearby azobenzene lead to azo dyestuff color by breaking chromophore, then the group whichcan be oxidated easily are attacked, such as benzene ring and naphthalene ring;...