Preparation And Degradation Of Antibiotics Of Visible-light-driven Bismuth Tungstate Photocatalysts

With the rapid deVelopment of modern industry,the problem of water pollution is becoming more and more serious.For the sustainable deVelopment of human civilization,it is urgent to find a green and efficient water enviro nment treatment method.As a green method driven by solar energy,photocatalysis technology has deVeloped rapidly in the field of Environmental pollution control and energy conversion in recent years.Up to now,a large number of related reports have confirmed that photocatalytic technology can successfully convert trace organic pollutants in water into non-toxic or low-toxic substances.HoweVer,traditional photocatalysts such as TiO₂ have disadvantages such as low quantum efficiency and no visible light response,which limit the practical application of photocatalysis.Therefore,the research on photocatalysts with high visible light response has become the focus of current research.Bi₂WO₆ is one of the most popular photocatalysts for visible light response.In this paper,We chose Bi₂WO₆ as the research material,and then selecteed a variety of different semiconductor materials to construct a heterojunction nano-photocatalytic material with Bi₂WO₆ to improve its photocatalytic performance.The main research contents are shown as follows:?1?The Bi₂WO₆ material with optimal photocatalytic activity was prepared by solvothermal method of ethylene glycol,including optimization of solvothermal reaction temperature and reaction time.Combined with the results of sample characterization and photocatalytic degradation of CIP,the Bi₂WO₆ material synthesized at 180?for 15h had the best photocatalytic activity,and its CIP degradation rate was about 83.6%.It could be seen from the calculation of the ultraviolet visible spectrum data that the band gap of the synthesized Bi₂WO₆material was about 2.70eV.?2?The g-C₃N₄/Bi₂WO₆ series heterojunction photocatalysts were successfully synthesized by both ethylene glycol solvothermal method and grinding-calcination method.Compared with pure g-C₃N₄ or Bi₂WO₆,the prepared g-C₃N₄/Bi₂WO₆heterojunction photocatalysts exhibited better photocatalytic activity,and the CIP degradation rate increased by more than 10%.The construction of the g-C₃N₄/Bi₂WO₆ heterojunction increased the specific surface area of the material,reduced the band gap of the material,facilitated the separation of photogenerated electrons and holes and hindered the combination of them,thereby effectively improving the photocatalytic activity.And at the same composite ratio,the content of the heterojunction in the g-C₃N₄/Bi₂WO₆ sample prepared by the solvothermal method was higher than that of the g-C₃N₄/Bi₂WO₆ sample prepared by the grinding calcination method.?3?The?-Bi₂O₃/Bi₂WO₆ series p-n heterojunction photocatalysts were successfully synthesized by ethylene glycol solvothermal calcination.Compared with pure?-Bi₂O₃ or Bi₂WO₆,the?-Bi₂O₃/Bi₂WO₆ heterojunction composite photocatalysts showed better photocatalytic activity,and the photocatalytic degradation rate of CIP increased by about 10%.The structure of?-Bi₂O₃/Bi₂WO₆p-n heterojunction promoted the migration of photogenerated carriers on the catalyst surface,hindered the recombination of photogenerated electrons and holes,promoted the surface redox reaction of the catalyst and enhanced the visible light catalytic activity of CIP degradation.?4?Fe₃O₄/Bi₂WO₆ and?-Fe₂O₃/Bi₂WO₆ heterojunction photocatalysts with good magnetic response were successfully synthesized by using PEG-6000 as adhesion fixative.The experimental results showed that both Fe₃O₄/Bi₂WO₆ and?-Fe₂O₃/Bi₂WO₆ nanocomposites exhibited excellent magnetic response properties,and it could be seen that both catalysts could be recovered and reused by using an external magnetic field.The degradation rate of CIP under visible light were about90%and 65%for Fe₃O₄/Bi₂WO₆ and?-Fe₂O₃/Bi₂WO₆,respectively.The heterostructure formed by Bi₂WO₆ and?-Fe₂O₃ after contact was not conducive to the photocatalytic reaction,thus leading to the degradation rate of CIP decline.