Research On The Efficiency Of The Degradation Of Nitrobenzene By CuO/CeO₂

Currently,the lack of water resources has become a global concern,mainly because the water environment is polluted and damaged.With the progress of world science and technology,urbanization and industrialization level improving year by year,all kinds of organic and synthetic chermicals have entered into people's life and production.At the same time,due to the use of organic pesticides and the emission of industrial wastewater,more and more difficult degradation organic pollutants are entering into the water.The nitrobenzene,one of the common pollutants,which is highly toxic and stable,is a serious threat to human living environment.In order to remove nitrobenzene in the water effectively,the paper is to use the heterogeneous Fenton-like oxidation technology,which has the advantage of better and higher degradation degree.The selection of suitable heterogeneous Fenton-like catalyst has very important significance to the technology used in practical engineering.Therefore,this paper aims to synthesize a high catalytic performance,less metal ion releasing and long life of the catalyst for the heterogeneous Fenton-like technology,which can effectively remove the nitrobenzene.In this paper,the catalyst CuO/CeO2 was separately prepared by four methods.And it was characterized by the methods of specific surface area(BET),scanning electron microscope(SEM)and X-ray diffraction(XRD).At the same time,the catalytic activity was discussed in the catalytic ozonation of nitrobenzene for the heterogeneous Fenton-like technology.Method M1 is more suitable for practical application through comprehensive consideration.The preparation conditions of CuO/CeO2 prepared by method M,were studied in this paper.The best preparation conditions of CuO/CeO2 were selected.These conditions were that the CuO content was 5%,calcination temperature was 400?,calcination time was 3h,and the support CeO2 calcination temperature was 400?.Under the best conditions,the heterogeneous Fenton-like catalyst CuO/CeO2 made the nitrobenzene removal rate reach 83.78%.When nitrobenzene was selected as a target pollutant,the other influencing factors of heterogeneous Fenton-like reaction system were studied.The experimental results indicated that under the conditions of reaction temperature 25?,CuO/CeO2 catalyst dosage 500mg/L,H2O2 dosage 12.5mmol/L,and solution pH 6,the nitrobenzene removal effect was the best,and the TOC removal effect was above 60%.The various inorganic ions in natural water contained HCO3-,CO32-,HPO42-,Cr,SO42-and NO3-can produce the different influence to a degree.Among these ions,HCO3-,CO32-,HPO42-and Cl-produced inhibition for the degradation and the inhibitory effect of CO3-was the strongest.SO42-and NO3-were almost no impact on the degradation reaction.The reaction mechanism of removing nitrobenzene when CuO/CeO2 existed was preliminarily discussed.It was concluded that the degradation reaction followed the hydroxyl free radical mechanism.The Cu2+ dissolution of the catalyst CuO/CeO2 prepared in the laboratory was only 0.105mg/L,approximately 0.49%of the catalyst Cu2+ content,and the amount of the Cu2+dissolution was rare in the reaction system.The catalyst had good settling properties,and was recycled and reusable for many times,so it's very important for the engineering application.