Preparation Of BiOCl-loaded Pine Needle Biochar-based Composite Material And Study On Photocatalytic Degradation Performance

With the development of the economy,the problem of water pollution is increasing seriously.At present,the most widely used pollutant removal method is photocatalytic degradation.In a wide range of photocatalysts,BiOCl has good stability and is non-toxic,and it has unique hierarchical structure and electronic properties,so it has good application prospect in dye wastewater treatment.However,BiOCl has a wide bandgap,cannot be excited in the visible light,and it is easy to disperse and dispersibility is not very good.So it needs to be further modified.Among the many modification methods,the coupling with the electron acceptor material is a common method.Biochar is a hot electron acceptor material in recent years.It has good electron conductivity and can improve the separation efficiency of electron hole pair.At the same time,due to its rich pore structure and large specific surface area,it has been widely studied in the catalyst carrier.Therefore,complex biochar and BiOCl in the field of photocatalysis will have an important application prospects.Specific studies are as follows:First of all,the pine needles were pretreated and prepared into pine needles biochar by tube furnace calcination namely thermal decomposition method.After treatment with hydrochloric acid,and then they were mixed with toluene to prepare modified pine needles biochar.Then flower like BiOCl which was prepared by solvothermal method and modified pine needles biochar were tube furnace by calcination,finally we can obtain BiOCl/C binary composite photocatalyst,this photocatalyst can be used for the photocatalytic degradation RhB solution.The BiOCl/C binary composite photocatalysts with the best photocatalytic degradation efficiency were studied by change the mass ratio of BiOCl and C,and characterized by SEM,TEM,PL,electrochemical tests and so on.The mass ratio of BiOCl to C at 3:4 has better degradation efficiency than that of the other mass ratio photocatalyst in photocatalytic degradation RhB solution under UV light,and the mechanism of photocatalytic degradation was put forward by mechanism experiment.Secondly,the Ag/BiOCl complex was prepared by photocatalytic reduction under UV light,then the Ag/BiOCl/C ternary composite photocatalyst was prepared through calcination Ag/BiOCl complex and modified pine needles biochar by tube furnace.The Ag/BiOCl/C ternary composite photocatalyst with mass ratio of 0.75:3:4 has shown the best photocatalytic degradation efficiency in photocatalytic degradation of RhB solution under visible light.After the SEM,XRD,TEM,XPS,EDS,PL,DRS and electrochemical tests,the various properties of the ternary composite photocatalyst were further understood,and put forward the probable mechanism of the photocatalytic degradation process.The ternary composite photocatalyst utilizes the surface plasmon resonance effect of the noble metal Ag,Ag as the electron donor,BiOCl as the electronic transmission medium and the biochar as the electron acceptor,which improves the separation efficiency of the photo-generated electrons and hole pairs during the photocatalytic degradation process,improve the photocatalytic activity.Finally,Ag/AgCl/BiOCl complex was prepared by partial reduction of AgCl/BiOCl heterojunction complex under UV light,and then Ag/AgCl/BiOCl/C quaternary composite photocatalyst was prepared by calcination Ag/AgCl/BiOC complex and modified pine needles biochar by tube furnace.In the test of photocatalytic degradation RhB solution under visible light,the S3 sample has shown the best degradation efficiency.After the experiments of SEM,XRD,TEM,XPS,EDS,PL,DRS,electrochemical test and the mechanism discussion,the mechanism of photocatalytic degradation process was put forward.In this photocatalyst,heterojunction is formed between AgCl and Bi OCl,and the noble metal Ag has a surface plasmon resonance effect,which can be used as an electron donor,under the visible light irradiation,the photo-generated electrons through AgCl and BiOCl are transferred to the conductor biochar which is acted as the electron acceptor,which promotes the separation of the photo-generated electron-hole pairs.This series of effects makes the composite photocatalyst in the visible region of the light response range has been further expanded to further improve the use of visible light in the solar spectrum So that the photo response range of this composite photocatalyst in the visible region has been further expanded because of the series of effects,and the use of visible light in the solar spectrum has been further increased.