Study On Treatment Of Organic Dye Wastewater By Photocatalysis-catalytic Wet Oxidation

With development of modern industry, a large number of organic wastewaterwas produced, the compositions of wastewater were complicated and existed as thedifficult degradable organic pollutants in water. As we all known, the wastewater wastoxic and difficult to reach to standard emission using conventional physicochemicaland biochemical methods, which caused very serious environmental pollution, andthe control of water pollution had become the current urgent problems. Therefore,many domestic and foreign research workers focused on seeking effective waterpollution treatment methods. Advanced oxidation technology was an importanttechnical method to the current direction of refractory organic wastewater treatment.This paper respectively used methyl orange and acid red GR as simulate pollutants, toexamine the treatment effect of the photocatalytic oxidation technology and catalyticwet oxidation technology. The photocatalytic-catalytic wet oxidation technologysystem was built, and active brilliant red X-3B as simulate pollutants was used, theeffect of various factors, finally fabricating kinetics equation was studied, and thenthe technology synergy mechanism and the industrial organic wastewater werestudied.Firstly,This paper studied the effect of the methyl orange solution’s degradationwhich used the technique of photocatalytic oxidation. Different morphology ZnOnanoparticle arrays was prepared by using hydrothermal method and their catalyticproperties were investigated under UV light with methyl orange solution as simulateorganic wastewater. And the growth mechanism of different morphology of ZnO wasanalyzed. These results showed that controlling the pH and adding different surfactantcould control the size of nanometer ZnO, and could get the nanometer ZnO of largespecific surface area and high catalytic activity of the catalyst. In order to overcomedefect of the single semiconductor of catalytic degradation efficiency of pollutants inthe process, TiO2, CuO were respectively composited with ZnO, the preparation ofnanometer TiO2/ZnO and CuO/ZnO composite catalyst, the results showed that thetwo kinds of semiconductor played a synergy in the degradation process, promoted the efficiency of the degradation of catalyst, the composite of nanometer CuO/ZnOcatalyst had the highest catalytic activity, effectively improved the effect of thetreatment of photocatalytic oxidation to deal with organic wastewater.Secondly,The treatment effect of acid red GR and industrial refractory organicwastewater were studied by catalytic wet air oxidation technology. The high catalyticperformanceCuO-ZnO-CeO2/γ-Al2O3was prepared with impregnation methodon the carrier of γ-Al2O3. And the catalyst was used to deal with simulated acid redGR dye biodegradable organic wastewater at atmospheric pressure. On the basic ofexperimental studies by single factor and orthogonal optimization, the optimaltreatment conditions of the wastewater treatment process were:600mg/L ofsimulated acid red GR refractory organic wastewater (COD value was396.85mg/L),reaction temperature was70℃, reaction time was2.5h, catalyst dosage was2.5g,30%H2O2dosage was0.5mL, pH was4.COD removal and decolonization ratereached86.13%and99.91%, respectively. The degradation effect was remarkable.Based on study of photocatalytic oxidation technology and catalytic wetoxidation technology research, the photocatalytic-wet catalytic oxidation process wasconstructed. Treatment process conditions of red X-3B dye analog refractory organicwastewater were studied by using the catalystCuO-ZnO-CeO2/γ-Al2O3and thisprocess. And optimization conditions by response surface methodology: the reactiontemperature was54℃, reaction time was2.7h, catalyst dosage was2.6g, dosagewas0.62mL, pH was3.4. At this point, the decolonization rate reached to99.33%.Kinetic studies of degradation of reactive brilliant red X-3B by thephotocatalytic-catalytic wet oxidation were carried out by applying ELKM kineticmodels and combining with experimental results. The results showed that the processcompliance with the pseudo-first-order kinetic model. And apparent reaction kineticrate constants increased with temperature increasing, and fitted the Arrheniusequation relationship with the reaction temperature, and the apparent activationenergy was32.79kJ/mol. The apparent kinetic equation was:The degradation path of simulation dye reactive brilliant red X-3B by the photocatalytic-wet catalytic oxidation process was analyzed by using UV-Vis, IR andGC-MS detection means. And the degradation mechanism of organic wastewatertreated by the process was inferred.Finally, the effect of refractory industrial organic wastewater treatment wascomprised the photocatalytic-wet catalytic oxidation process and wet catalyticoxidation process. And the results showed that the photocatalytic-wet catalyticoxidation process required lower temperature and less hydrogen peroxide dosingwhile it attained better processing efficiency, and reduced the energy consumption. Itwas an environmental friendly process.