Preparation And Degrade Antibiotics Of BiOBr-based Composite Photocatalyst

In recent years,the antibiotic wastewater that has not been effectively treated is directly discharged into the environment,causing serious pollution to the nature.Nowaday,how to effectively treat antibiotic wastewater has become an important issue.As a simple,efficient and no secondary pollution green oxidation technology,semiconductor photocatalysis technology has great prospect in the treatment of antibiotic wastewater.BiOBr is a kind of semiconductor photocatalyst which has been widely used in photocatalytic degradation of pollutants due to its suitable bandgap width,strong visible light absorption capacity and stable physicochemical properties,but photoelectron-hole pair quick compound makes it difficult to improve photocatalytic efficiency.In order to achieve higher degradation efficiency,we combine BiOBr nanosheets with different dimensional materials such as ZnS?0D?,CNTs?1D?,g-C₃N₄?2D?and GO?2D?,including ZnS/BiOBr,CNTs/BiOBr and g-C₃N₄/GO/BiOBr nanocomposite photocatalyst.The effects of structural composition,microstructure,light absorption,separation of photogenerated electron-hole pairs and transfer efficiency on photocatalytic properties are investigated,the photocatalytic mechanism of composites.The specific research contents are as follows:?1?A series of ZnS/BiOBr composite photocatalysts with different ZnS contents were prepared by hydrothermal method.Characterization of composites by XRD,Raman,XPS.The microstructure of the composites was observed by SEM and TEM.It was found that the ZnS nanoparticles were spherical with a diameter of about 20 nm and uniformly attached to the BiOBr nanosheets.UV-vis.absorption spectroscopy showed that the ZnS/BiOBr composite had a wider light absorption range than BiOBr.Under light irradiation,the 2.5%ZnS/BiOBr composites can degrade 82%tetracycline in 25 minutes which has high photocatalytic degradation efficiency.The photocurrent response,EIS and capture agent experiments were used to determine the transfer path of charge during the catalytic reaction and the active groups that act as the main catalyst.a possible photocatalytic reaction mechanism was proposed.?2?A series of CNTs/BiOBr composite photocatalysts with different CNTs content were prepared by hydrothermal method.The composition of the material was characterized by XRD,FT-IR,Raman,XPS.The microstructure of the sample was observed by SEM and TEM.It was found that the carbon nanotubes were tubular with a diameter of about 20 nm and attached to the BiOBr nanosheets.The UV-visible absorption spectrum showed that the light absorption capacity of CNTs/BiOBr composites was significantly enhanced.1%CNTs/BiOBr had the best photocatalytic ability to degrade tetracycline.Under light irradiation,1%CNTs/BiOBr composite photocatalyst can degrade 85.5%tetracycline in 25 minutes.The photocurrent response,EIS and capture agent experiments were carried out to investigate the transfer path of photogenerated carriers in photocatalytic reactions.the degradation mechanism of composite photocatalysts was proposed.?3?g-C₃N₄ prepared by calcination method and GO prepared by Hummers method,were used as precursors.A series of g-C₃N₄/RGO/BiOBr composites with different contant were prepared by hydrothermal method.The existence of g-C₃N₄,RGO and BiOBr materials in composites was confirmed by XRD,FT-IR,Raman and XPS.By observing SEM and TEM image,it can be found that the three phases were well combined,and the size of the BiOBr nanosheets was significantly reduced due to the addition of g-C₃N₄ and RGO.Under light irradiation,the g-C₃N₄/RGO/BiOBr composites had significantly higher photocatalytic degradation ability to tetracycline than single-phase and two-phase composites,degradation rate reached 92.1%in 50minutes.The photocurrent response,electrochemical impedance and capture agent experiments were carried out to investigate the transfer path of carriers in the catalytic process and the active groups which played a major role in the catalytic reaction were determined.Based on this,the Z-scheme degradation system was proposed.