Preparation Of Mn-Ce@Ac Catalyst And Study On Ozone Catalytic Oxidation

Industrial wastewater may contain heavy metals,oil emulsions,inorganic and organic compounds,which are difficult to remove due to their solubility or persistence in water and the presence of refractory compounds.The development of advanced oxidation technology to treat water pollution has become a research focus in the field of low-concentration organic wastewater treatment.Ozone catalytic oxidation technology has received widespread attention because of its mild reaction conditions,relatively low cost,and excellent treatment effects on low-COD water.In this paper,the preparation of activated carbon-supported manganese-cerium catalyst and its application in the treatment of low-concentration aniline organic wastewater in the ozone catalytic oxidation technology are carried out.First,the preparation of the heterogeneous ozone catalytic oxidation catalyst was optimized.Different from the traditional equal-volume impregnation method or excessive impregnation method,this topic optimizes the preparation of the catalyst.The addition of ultrasound and the rotary evaporation process make the precursor solution more uniform and fully absorbed.The use of rotary evaporation can ensure the accurate loading of active components and the loading results were verified by ICP,XRD and other characterization methods.Secondly,the effects of the catalysts without active metal components and the supported metal oxide catalysts with activated carbon as the carrier for the catalytic oxidation of aniline by ozone were studied.The mixtures of manganese,cerium and manganese-cerium in different proportions were used as the active components.The loading amount of the catalyst used in the experiment is 5wt%,10wt%,15wt%,20wt%,and the composite catalyst with different ratios of manganese and cerium has a loading amount of 20wt%,and the molar ratio of manganese to cerium is 1:1,1:2,1:3,2:1,3:1.The aniline concentration in the water sample and the COD content of the water were used as test indicators to evaluate the reaction activity of the catalyst.The experiment adopted the batch reaction method to find the most suitable catalyst and carried out a series of characterization of the catalyst.10wt%Ce@20-40 mesh AC is the best option,and its COD removal rate(reaction time 150 minutes)is 88.89%.The cerium-manganese composite catalyst generally showed better reactivity than the manganese catalyst alone.The COD removal rate of the highest one(reaction time 150 minutes)was 84.39%,but it was still inferior to the cerium catalyst.In summary,among the three catalyst systems,10wt%Ce@20-40 mesh AC is the most comprehensive.Finally,the catalyst with the best reaction activity is selected to optimize the reaction conditions.The experimental conditions of 10wt%Ce@20-40 mesh AC were studied,mainly from the dosage of the catalyst,the initial model compound(aniline)concentration,the initial solution pH,and the addition of quencher to study the effect of the reaction results.At the same time,gas chromatography-mass spectrometry(GC-MS)is also used to analyze the water in the reaction.The results show that the pH of the initial solution with the best reaction activity is 10.07.Ozone catalytic oxidation is more suitable for low-concentration model compound concentrations.The addition of the quencher tert-butanol leads to a significant decrease in the degradation rate of aniline.Hydroxyl radicals are generated in the process of aniline.The main intermediate reaction products that catalyze the degradation of ozonated aniline are formanilide,nitrobenzene,azobenzene,indole and N’-phenyloxamide.In summary,the activated carbon-based supported cerium catalyst is very effective for the treatment of low-concentration aniline organic wastewater by the ozone catalytic oxidation technology.