Preparation Of Modified Carbon Nitride Photocatalytic Materialand Degradation Of Tetracycline And Tylosin In Water

Faced with the current serious energy crisis and environmental problems,photocatalysis,as a kind of technology that can convert solar energy into chemical energy,it can well solve the energy and environmental problems facing human beings at present.Compared with traditional photocatalysts,graphite-like carbon nitride（g-C₃N₄）has the advantages of simple preparation,low cost and good stability.However,as the current requirements for catalysts become higher and higher,g-C₃N₄has gradually revealed many shortcomings in practical applications,such as high carrier compound rate,small specific surface area,poor visible light absorption performance and powdered catalysts that are not easily recycled and easily cause secondary pollution,which have a great inhibiting effect on the photocatalytic performance of g-C₃N₄.For the shortcomings of g-C₃N₄,in this paper,it is modified by changing the energy band structure,increasing the specific surface area and constructing heterojunctions to improve the photocatalytic activity and practical performance of g-C₃N₄.In this paper,Tb-doped porous g-C₃N₄（TCN）photocatalysts were prepared by nitric acid treatment and their modification by doping with the rare earth element terbium（Tb）.In order to optimise the amount of Tb doping,by scanning electron microscopy,X-ray diffraction（XRD）and photoluminescence（PL）tests,the effects of terbium ion doping concentration on the structure,morphology,photoelectric properties of the catalyst,the photocatalytic degradation of tetracycline hydrochloride（TC）and Tylosin（TYL）and the photocatalytic activity of the catalyst were studied.The results showed that Tb3+was successfully doped and 0.01 TCN exhibited the best photovoltaic properties and photocatalytic activity.The photoluminescence results,among others,were obtained.In addition,the stability,recoverability and toxicity of the samples were evaluated by replicate experiments of photocatalytic degradation of TC and seed germination experiments.The main active species were investigated by radical trapping experiments and a possible mechanism for the 0.01TCN catalyst to improve the photocatalytic degradation efficiency was proposed.To further improve the photocatalytic activity of g-C₃N₄,the narrow forbidden band semiconductor ZnIn₂S₄（ZIS）was formed into a heterojunction with TCN.To optimise the doping amount of TCN,the effects of terbium ion doping concentration on the structure,morphology,optoelectronic properties and photocatalytic activity of the photocatalyst were investigated by scanning electron microscopy,X-ray diffraction（XRD）techniques as well as photoluminescence（PL）tests and photocatalytic degradation of tetracycline hydrochloride（TC）and tylosin（TYL）.The results show that ZnIn₂S₄（ZIS）and TCN successfully formed the heterojunction ZnIn₂S₄/TCN（ZIS/TCN）and 150ZIS/TCN exhibited the best photovoltaic properties and photocatalytic activity.Photoluminescence results,etc.In addition,the stability and recoverability of the samples were evaluated by repeated experiments of photocatalytic degradation of TC.The main active species were investigated by radical trapping experiments and a possible mechanism for the 150ZIS/TCN catalyst to improve the photocatalytic degradation efficiency was proposed.In order to improve the photocatalytic efficiency of photocatalysts and to improve their recyclingratetoreducesecondarypollutionofphotocatalysts,PAN/PDA/Tb/g-C₃N₄/ZnIn₂S₄（PPTZ）photocatalytic films with"sandwich"structure were prepared by electrostatic spinning technology.The effect of TCN addition on the structure,morphology,photoelectric properties and photocatalytic activity of PPTZ was investigated,and it was found that the PPTZ composite films were successfully prepared.The stability,recoverability and toxicity of the samples were evaluated through replicate experiments of photocatalytic degradation of tetracycline with seed germination experiments.The possible mechanism of photocatalytic degradation of PPTZ photocatalytic films was proposed through free radical trapping experiments.In this paper,the layered photocatalytic films were prepared by doping the rare earth element Tb,forming heterojunction with sulfur indium zinc and using polyacrylonitrile electrospinning film as substrate film.The photocatalytic performance of g-C₃N₄was greatly improved,and the safety of the catalyst was proved by toxicity test.The prepared PPTZ photocatalytic film can better improve the recycling performance of photocatalyst,and the photocatalytic material can be better applied to the actual production and life.