| Phenolic wastewater discharged from industrial and agricultural production has a great impact on the environment,so removing phenolic compounds in wastewater is the top priority of environmental treatment.Semiconductor photocatalysis technology has attracted much attention in the treatment of phenol wastewater in recent years.Nano-Bi2O3has attracted much attention because of its special electronic structure and excellent photocatalytic degradation performance.However,the application of nano-Bi2O3in the field of photocatalysis is limited by its relatively large band gap,narrow absorption range of visible light and high electron-hole pair recombination rate.Therefore,in order to improve the photocatalytic activity of nano-Bi2O3,this paper modified nano-Bi2O3by heterojunction and applied it to photocatalytic degradation of phenol,and the conclusions are as follows:1 First,concurrent flow controlled rate precipitation method synthesis of nano-Bi2O3,after a certain concentration of gets to in situ conversion of nano-Bi2O3,preparation quality percentage respectively 0wt%、30wt%、60wt%、70wt%、80wt%、90wt%、100wt%of BiOBr/α-Bi2O3heterojunction photocatalyst materials,and through to simulation under visible light irradiation on photocatalytic degradation of phenol wastewater containing phenol solution to evaluate the photocatalytic performance.The results showed that the degradation rates of pure Bi2O3 0wt%and pure BiOBr 100wt%were 54.7%and 47.77%,respectively,after exposure for 60 min.When the composite ratio of BiOBr and Bi2O3is 70wt%,the best removal effect is obtained.After 60 min,the removal rate is as high as 92.08%,which is significantly better than the degradation rate of pure substances under the same conditions.Therefore,the formation of the heterojunction structure can improve the photocatalytic activity of the photocatalyst.Through the study of the degradation mechanism,the main active substance in the system is determined to be·O2-,and·OH also plays a certain role.2 By controlling the molar ratio of BiNO3 3·5H2O and KCl,Bi12O17Cl2/α-Bi2O3heterojunction photocatalyst materials with molar ratio of BiNO3 3·5H2O and KCl of 6:1、7:1、8:1、9:1、10:1 and 1:0 were synthesized by solvothermal method combined with calcination method.The effect of heterojunction materials on the photocatalytic degradation of phenol was also studied.The results showed that under the same conditions,the degradation rate of pure nano-Bi2O3prepared by solvothermal method and calcination method was only 51.93%.When KCl was added,the photocatalytic activity of the sample was significantly enhanced.When the molar ratio of BiNO3 3·5H2O and KCl is 8:1,the sample had the highest degradation rate95.29%.At the same time,the sample has a good repeatability after five cycles. |
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