Advanced Treatment Of Petrochemical Storage Wastewater By Heterogeneous Ozonation

As a basic industrial industry to promote economic development in China,the petrochemical industry expands its development scale,and the refractory wastewater from petrochemical storage tank cleaning also increases.With the further improvement of national and local discharge standards,the advanced treatment process for such low-concentration refractory wastewater still needs to be further explored.In this paper,the advanced treatment process of petrochemical storage tank-cleaning wastewater is studied.Choose different catalyst carrier in the process of research as well as a variety of metal ions,load the ozone catalytic oxidation experiments,through the evaluation of treatment object target pollutants removal effect better removal effect of combination,and optimize the catalyst preparation conditions,the preparation of a kind of the target pollutants removal effect is better than activated carbon catalyst metal(CFMA),Heterogeneous ozone catalytic oxidation system CFMA/O3 was established.Taking single ozonation as the control,the effects of the amount of ozone in the reaction system,the amount of catalyst and pH of the reaction on COD removal were studied.The CFMA/O3/H2O2 reaction system was established by introducing trace H2O2.After determining the factors affecting the reaction system,the response surface method was used to analyze the optimal experimental conditions and the generation mechanism of the main oxidation species in the reaction and the oxidation way of COD degradation were deeply studied.The relative changes of benzene species in tank cleaning wastewater from petrochemical storage before and after ozonation were analyzed by headspace solid phase microextraction(GC-MS)and gc.Through the research,the conclusions are as follows:(1)In the study of ozone catalytic oxidation of tank cleaning wastewater from petrochemical storage,the CFMA catalyst with better COD removal effect was prepared after the selection of catalyst carrier particles and active components.The optimum preparation conditions of CFMA catalyst were as follows:ultrasonic impregnation temperature 25?,impregnation time 2h;Drying at 70? for 12h;Calcination at 450? for 4h;The molar ratio of Cu:Fe:Mg is 1:2:1.(2)The characterization results of the catalysts are as follows:The specific surface area of the carrier particles increases after the BET surface is modified by alkali,and the surface of CFMA catalyst has a mesoporous structure;XPS showed that the ratio of adsorbed oxygen to lattice oxygen on the catalyst surface was higher,which was conducive to the formation of hydroxyl groups on the catalyst surface.The presence of Cu(?),Fe(?)and Mg(?)on the surface load is beneficial to promote electron transfer.(3)In the study of ozone catalytic oxidation,compared with the COD removal effects of single O3,O3/CFMA,O3/H2O2 and O3/UV reaction systems on tank cleaning wastewater from petrochemical storage,heterogeneous ozone catalytic oxidation system CFMA/O3 shows better removal effects.(4)After the CFMA/O3/H2O2 reaction system was established by adding trace H2O2 synergistic heterogeneous ozone system,the COD removal effect of tank cleaning wastewater from petrochemical storage was effectively improved.After determining the factors that affect the reaction system greatly through single factor experiment,response surface analysis was carried out to determine the ozone dosage of 5mg/(L·min),catalyst dosage of 14g/L,reaction pH of 8.5,H2O2 dosage of 1.5 mL/L under the conditions of the experiment,the COD removal rate is 73.2%.TBA radical quenching experiment was conducted to verify that adding a small amount of H2O2 in heterogeneous ozone catalytic system can initiate the reaction of removing target pollutants.(5)Comparison of ozone heterogeneous experiment,free radical inhibition experiment and superoxide free radical inhibition experiment was carried out by mixing simulated wastewater.In the process of heterogeneous ozone catalytic oxidation of BTEX,the contribution of indirect oxidation pathway using ·OH oxidation was much greater than that of direct ozone oxidation.(6)For the CFMA/O3/H2O2 reaction system established in this project,the cost of catalyst,equipment,reagent and operation is comprehensively calculated.It costs 3.163 yuan per cubic meter for the treatment of tank and tank cleaning wastewater from petrochemical storage.