Study On Ozone Catalytic Oxidation Of Phenol In Coal Chemical Wastewater

With the rapid development of my country’s industrialization,coal gasification technology is considered to be one of the alternatives to energy such as oil and natural gas.However,during the coal gasification process,various organic pollutants including phenols will be produced,and their toxicity and persistence inhibit the biodegradation and other activities of the subsequent treatment process.In this paper,phenol was used as the main target pollutant to study and prepare catalysts with good catalytic activity,in order to achieve high degradation efficiency and provide technical support for the treatment of coal gasification wastewater containing phenols.Ceramic honeycombs have a parallel longitudinal channel structure,which is less prone to deposition and blockage on the backwater surface than carriers such as small balls.In this paper,ceramic honeycombs are used as carriers,and Cu（NO₃）₂·3H₂O and Na OH are used as precursors to explore the synthesis of different preparation processes.The ceramic honeycomb catalyst catalyzed the degradation of phenol wastewater by ozone oxidation.It was determined that the loading capacity of the active components was enhanced after the aluminum sol coating was pretreated with nitric acid,and the catalyst performance was improved,and the loading effect was improved by dipping in a constant temperature water bath.Among them,the study found that the coating coating process has the best loading effect when the single coating time is 1 h,and the coating is repeated three times,with a loading amount of 34%,and the obtained catalyst has a good catalytic ozone oxidation effect.In this paper,CuO/Al₂O₃/ceramic honeycomb catalysts were prepared by surface coating impregnation precipitation method,and the influence of various process parameters on the properties of catalysts during the preparation process of impregnation precipitation method was investigated.It was determined that the Al₂O₃/ceramic honeycomb carrier with triangular pore mesh was immersed and precipitated in 0.4 mol/L Cu（NO₃）₂·3H₂O and Na OH solution,and calcined at 400℃for 3 h as the best preparation condition.The obtained catalyst was characterized by XRD,BET,FTIR,SEM-EDS and XPS.The results showed that the peak shape and position of the main crystal phase did not change significantly before and after the ceramic honeycomb was loaded,but the peak intensity decreased,and the catalyst morphology,The specific surface area is optimized,which proves the successful loading of the active components.The Cuelement after loading mainly exists in the divalent form of Cu-O bonds,which can promote the adsorption and decomposition of ozone and improve the effect of catalytic ozone oxidation.By optimizing the experimental conditions,it was determined that the catalytic ozonation system was constructed under the conditions of ozone concentration of 1.2 mg/L,effective catalyst filling height ratio of 0.38 and alkaline conditions.In the treatment of actual phenol-containing wastewater,the removal rate of phenol can reach 98%after 120 min of reaction,the removal rate of COD can reach 68%,and the removal rate of TOC is 44%.The ozone utilization rate measurement and active substance capture experiment of the catalytic ozone oxidation system showed that the ozone utilization rate increased from 31%to 65%when the CuO/Al₂O₃/ceramic honeycomb catalyst catalyzed the ozone oxidation of phenol-containing wastewater,and the oxidation reaction followed the hydroxyl radical mechanism.In this study,CuO/Al₂O₃/ceramic honeycomb catalysts were prepared by surface coating,dipping and precipitation.The constructed catalytic ozone oxidation system has high degradation efficiency in the treatment of phenol-containing wastewater,which provides a useful reference for the treatment of phenolic wastewater and coal gasification wastewater.