Preparation Of Iron-containing Catalysts And Catalytic Ozonation Degradation Of Phenol

Phenol was a common chemical and an important raw material in industry,and it was widely used in the production and synthesis of resins,pesticides,preservatives and drugs.As a result of large-scale generation and application for a long time,a large number of lakes,farmland and groundwater were polluted to varying degrees,which posed a threat to water environment and human health.Therefore,it is necessary to develop stable and efficient technology to treat phenol in water environment.At present,the main technologies of phenol removal in water were adsorption,membrane separation,biological method and advanced oxidation processes.Compared with other methods,advanced oxidation processes was an environment-friendly treatment technology with high efficiency,stability and no secondary pollution.Catalytic ozonation was one of the most representative advanced oxidation processes.In order to overcome the disadvantages of poor stability of most catalysts and easy dissolution of metal ions,stable and efficient LaFeO₃-180 catalysts and Fe/Ag,Fe/Cu bimetallic catalysts were prepared by hydrothermal synthesis and metal substitution methods respectively.These iron-containing catalysts were characterized by SEM,XRD,BET and hydroxyl density on the surface of the catalysts.The effects of reaction conditions?ozone concentration,catalyst dosage and initial solution pH?on the removal of phenol by catalytic ozonation were studied.The recycling performance of catalysts and the mechanism of catalytic ozonation were discussed.The results showed that LaFeO₃-180 catalyst,Fe/Ag and Fe/Cu bimetallic catalyst exhibited good catalytic performance in the process of catalytic ozonation of phenol.Under the optimum conditions of ozone concentration of 7.3 mg/L,catalyst dosage of1.0 g/L and initial pH of 6.3,the removal efficiency of phenol and COD_Crr in LaFeO₃-180/O₃ system reached 100%and 81.8%±2.6%,respectively,after 60minutes.Under the optimum conditions of ozone concentration 7.3 mg/L,catalyst dosage 2.0 g/L and initial pH 6.3,the removal efficiencies of phenol by Fe/Ag/O₃ and Fe/Cu/O₃ systems were 100%and 99.7%±0.2%,respectively,and COD_Crr removal efficiencies were 72.2%±3.2%and 63.9%±2.2%,respectively,after 60 minutes.After four cycles,the removal efficiencies of phenol and COD_Crr in LaFeO₃-180/O₃system decreased by 2.1%and 8.5%,respectively.In Fe/Ag/O₃ system,the removal efficiencies of phenol and COD_Crr decreased by 2.4%and 11.1%,respectively.It was confirmed that both LaFeO₃-180 and Fe/Ag bimetallic catalysts had great stabilities.The free radicals in LaFeO₃-180/O₃ system and Fe/Ag/O₃ system were captured.It was confirmed that the catalytic ozonation reaction system was mainly indirect ozone oxidation,supplemented by direct ozone oxidation.In this study,several iron-containing catalysts were prepared,and these catalysts exhibited stable and efficient removal performance in the process of catalytic ozonation for phenol degradation.Therefore,this technique has promising potential in the treatment of phenol-containing water.