Preparation Of Iron Oxychloride And The Efficiency Study Of Catalytic Ozone To Remove Dimethyl Phthalate

There is a serious shortage of water resources in China,and research on the recycling of sewage is an effective way to alleviate the problem.Heterogeneous catalytic ozonation is one of the advanced oxidation technologies with many advantages,such as a good degradation effect on most organic compounds in sewage,strong oxidation ability,simple process and no secondary pollution.In catalytic ozone oxidation technology,iron-based catalysts have attracted much attention because of their wide distribution and high catalytic efficiency.An improved method is applied to prepare oxy-ferric chloride(FeOCl)catalyst.The physicochemical properties of the prepared catalyst are characterized by means of XRD,SEM,FTIR,TG,BET and Zeta potential.Dimethyl phthalate(DMP)was selected as the degradation target,and the removal rate of DMP was taken as the experimental index.The catalyst with the best catalytic activity was selected to explore the effects of catalyst concentration,initial p H value and reaction temperature on the degradation efficiency.Combined with the results of characterization,the structure-activity relationship between the physical and chemical properties of the catalyst and the catalytic effect was analyzed.The experimental results showed that the removal rate of DMP increased with the ozone dosage and catalyst concentration.it increased first and then decreased when the initial p H value of the solution changed from 3 to 11,which was same to the reaction temperature changed from 5? to 45?.The removal efficiency of DMP is optimal when the p H value is 9 and the reaction temperature is 25?.The initial concentration of DMP is negatively correlated with the removal rate of DMP.The results of the comparison of ozone mass transfer and COD test showed that the presence of the catalyst can improve the mass transfer efficiency of ozone and the degree of mineralization of DMP.The existence of ·OH was directly detected by electron paramagnetic resonance(EPR)technology,which indicated that the mechanism of catalytic ozone oxidation was in accordance with the hydroxyl radical theory.The mechanism of ·OH was indirectly verified by the reaction of tert-Butanol with ·OH,and the yield of ·OH in the reaction system was further determined.Finally,the mechanism of the decomposition of OH catalyzed by FeOCl was deduced.