Efficiency And Mechanism Of Antibiotics Degradation In Wastewater By Catalytic Ozonation

Catalytic ozonation has recently been considered as a competitive technique for advanced treatment,Fe-based materials are widely used as catalysts for heterogeneous catalytic ozonation due to their excellent catalytic performance and the abundance of Fe in nature.In this study,Fibrous nano-silica supported iron?Fe-KCC-1?,Ce_0.1Fe_0.9OOH,Fe₃O₄/MWCNTs and Fe₃O₄-CeO₂/MWCNTs composite were self-prepared and characterized.Then,sulfamethazine?SMT?,dimethyl phthalate?DMP?,p-hydroxybenzoic acid?p-HBA?,carbamazepine?CBZ?and municipal secondary effluent?MSEF?were chosen as model pollutants in this study.The degradation and mineralization efficiencies,and influencing factors were examined.Possible degradation pathways and catalytic mechanism were proposed.Moreover,the combined catalytic ozonation and BAF were tested on the degradation of effluent organic matters in MSEF.The main results obtained are as follows:1 ? Ce_0.1Fe_0.9OOH was prepared by isomorphous substitution method,cerium was successfully doped in the goethite;Fe-KCC-1 was prepared by hydrothermal method,which has a high specific surface area?464.56 m²/g?;By co-precipitation method,nano Fe₃O₄/MWCNTs and Fe₃O₄-CeO₂/MWCNTs were prepared,and Fe₃O₄-CeO₂/MWCNTs showed a uniform structure,large amount of metal oxide particles attached on MWCNT.2?With the addition of Fe-KCC-1 and Ce_0.1Fe_0.9OOH,the mineralization of SMT was obviously enhanced in the presence of catalysts,which was 1.6 and 1.74 times higher than ozonation alone,respectively.Moreover,degradation efficiencies of DMP and p-HBA were higher in Fe₃O₄/MWCNTs–O₃ system than that in single ozonation system.3?Catalytic ozonation systems showed good catalytic oxidation ability in a wide range of pH.In the catalytic ozonation system,ozone dosage,the concentration of catalyst and the initial concentration of antibiotics showed an different influence on antibiotics degradation.4?The degradation pathways of antibiotics were proposed according to the detected degradation intermediates;Possible catalytic mechanism were reported by exploring the effect of free radical scavengers and comparing the differences between newly and used catalysts.5?The advanced treatment of municipal secondary effluent was performed by catalytic ozonation using Fe₃O₄-CeO₂/MWCNTs.Moreover,the combined catalytic ozonation and biological aerated filter was effective for the reduction of COD,which reached 60%.