Preparation Of Microwave Enhanced Wet Peroxide Oxidation Catalyst And Its Mechanism For Quinoline Removal

As a typical industrial wastewater,coal chemical wastewater(CCW)contains refractory organic pollutants.Even the secondary biological process is introduced to treat the CCW,the effluent qualities cannot meet the relevant discharge standard.Correspondingly,developing an advanced treatment process with high efficiency and stability to address this issue has become a research focus in the field of wastewater treatment.Due to its high oxidation speed and high processing efficiency,catalytic wet peroxide oxidation(CWPO),one of the advanced oxidation technologies,has attracted wide attention.In the meantime,the combination of micro-wave(MW)and advanced oxidation technology has also drawn considerable attentions recently in the wastewater treatment fields.Thus,the aim of this dissertation is to combine the MW and CWPO(MW-CWPO)to achieve synergies effect,and to develop supported catalysts,to explore the catalytic mechanism,to investigate the performance factors and conditions of the reaction system on organics degradation,to discuss and analyst degradation mechanism of MW-CWPO.It is believed that this research can lay a solid foundation for applying MW-CWPO system in the advanced treatment of CCW.A bimetallic compound catalyst based on Cu was developed for MW-CWPO system.Besides,the characterization results of Cu/Ni-catalyst and Cu-catalyst showed that after doped with Ni,the metal particles on the surface of the Cu/Nicatalyst were smaller,the distribution was more uniform and the content of chemical adsorption oxygen on the surface of the catalyst was increased.The research on the catalytic mechanism of MW-CWPO demonstrated that MW-CWPO complies to ·OH oxidation mechanism.Furthermore,according to the effect of the addition of tertbutanol and carbon tetrachloride on the degradation of the target contaminants,it can be deduced that both ·OH and O2·-were involved in the degradation process of the pollutants in the MW-CWPO process and the contribution of ·OH was greater than O2·-.MW-CWPO systems was established for the degradation of quinoline.The experimental results shown that MW-CWPO system has good catalytic degradation performance,efficient effect of organic removal and high degree of mineralization.The effects of Microwave power,reaction temperature and hydrogen peroxide dosage on the removal of quinoline is greater,whereas the initial solution pH(3 ~ 8)and the catalyst dosage(2 ~ 6 g/L)have little effect on the removal of quinoline.The production of formic acid,acetic acid,oxalic acid,succinic acid,glycolic acid and nitrate could decrease the p H of the reaction system,maintaining the efficient oxidation performance of the system under neutral conditions.MW-CWPO system was used to the treatment of coal chemical biological secondary effluent in intermittent operation,the effects of several factors on the system was studied.The result of GC-MS analysis before and after treatment indicated that MW-CWPO system has an effective removal of phenols,ketones,nitrogen-containing organic compounds in the effluent of coal chemical industry.The system has certain significance for the employing of MW-CWPO oxidation technology in actual treatment of wastewater.The data of quinoline removal by MW-CWPO process fitted the pseudo-firstorder reaction model well.The rate constant increased with the increased of MW power,H2O2 dosage and reaction temperature.MW-CWPO process had a very significant synergistic enhancement effect and the synergistic factor was as high as 7.88 under MW 500 W and temperature 333 K.Under the respective optimal conditions,the activation energy of MW-CWPO system was19.15 k J/mol,implying that MW system was a diffusion controlling process.The degradation of quinoline in water by MW-CWPO oxidation system mainly follows the oxidative degradation mechanism of ·OH,that is,starting from the benzene ring of quinoline molecules by hydroxyl radicals,and thus form a series of organic compounds containing pyridine ring.