Construction Of Microwave-assisted Wet Catalytic Oxidation Reaction System And Treatment Of Coal Chemical Wastewater

It is difficult for biochemical method to remove organic pollutants in the coal chemical water,making biochemical effluent water quality is hard to meet.Therefore,a reliable and advanced treatment method for coal chemical biochemical secondary effluent re-treatment is very necessary.Wet H2O2 catalytic oxidation(CWPO)as a kind of deep processing method,favored due to its mild reaction conditions,the reaction speed,no secondary pollution and other characteristics.Microwave technology is a mature and efficient low-cost energy supply technology.The combination of the formation of the microwave-assisted catalytic wet hydrogen peroxide oxidation process(MWCWPO),provides a new way of thinking to the depth of treatment of refractory industrial wastewater.In this study,Cu Ox-NiO/AC catalyst was prepared by impregnation and precipitation method with copper and nickel as active component and granular activated carbon as carrier,and the quinoline was degraded by MWCWPO system.The catalytic performance of Cu-Ni/AC catalyst prepared by two methods was optimized and compared.The influence of catalyst preparation method on the catalyst structure was further studied by a series of characterization methods.The experimental results showed that the catalyst prepared by the precipitation method has better effect on the degradation of the pollutants and the optimum conditions for the preparation of the supported catalyst by the precipitation method are as follows: the mixed concentration of copper nitrate and nickel nitrate is 0.2 mol/L,the concentration of ammonia in the precipitant is 0.25 mol/L,the ratio of active group of copper nitrate and nickel nitrate is 4: 1,the dosage of precipitant is reverse addition,the calcination temperature is 300 ? and the calcination time is 4h.After the characterization of the supported catalyst,it was found that the active fraction of the Cu-Ni / AC catalyst prepared by the precipitation method was smaller,the grains were more evenly distributed in the granular activated carbon,the specific surface area of the catalyst was larger,which is the main reason for the better catalytic performance of the catalyst for the preparation of supported catalysts by precipitation.The influence of different microwave cavities on the uniformity of microwave distribution was discussed by HFSS electromagnetic simulation software,and the cavity of microwave reactor was optimized.The target pollutants of coal chemical wastewater were used to optimize the effect of the microwave reactor on the treatment of pollutants.The catalytic performances of the catalysts prepared by the two methods were investigated.The removal efficiency of the pollutants in different reaction systems was compared,and the actual operating conditions and the stability of the catalysts were studied.The results showed that the microwave uniformity in the loaded water was better in cylindrical microwave cavity than octahedral microwave cavity and than rectangular microwave cavity.The optimized microwave device had better removal of pollutants.The superiority of MWCWPO process had been proved.The optimum reaction temperature and effective hydraulic retention time were 60 ? and 1.12 min respectively.The microwave power and catalyst dosage were not affected by MWCWPO system in a certain range.The results showed that the reaction temperature and effective hydraulic retention time were the controlling factors of MWCWPO process.Under the conditions of initial dosage of H2O2 0.4 mol/L,water quality could reach a level a standard of the "Integrated Wastewater Discharge Standard".The dissolution rate of copper and nickel ions in the continuous flow experiment was much lower than that of the discharge standard.After 7 times of continuous use,the removal rate of TOC was decreased by 5% and the catalyst stability was high.In order to improve the treatment capacity of MWCWPO reactor for wastewater treatment,a microwave reactor with a treatment capacity of 10 t / d was designed.The diameter,height,number of microwave sources and microwave cavity size of the microwave reactor were discussed,and the microwave reactor system was constructed.