Photocatalytic Degradation Of Fluoroquinolones By Modified Bismuth Tungstate

The problem of water pollution caused by antibiotic abuse is threatening the sustainable development of human society.It has become a key research direction to seek environmental,efficient and sustainable means to solve the current common dilemma of mankind.Semiconductor photocatalytic degradation of organic pollutants has attracted widespread public attention in the past decades due to its good application potential in environmental pollution remediation and other fields.In recent years,bismuth based photocatalytic materials have attracted great attention due to their light utilization,high separation rate of photogenerated hole electron pairs,and strong redox ability.There are abundant reserves of bismuth resources in China,bismuth based nanomaterials have attracted extensive attention due to their low toxicity,high stability,high catalytic activity and other characteristics.Among them,bismuth tungstate（Bi₂WO₆）has been widely studied in the field of photocatalysis because of its unique layered structure,good visible light response and high stability.As the simplest bismuth oxide,Bi₂WO₆ has the advantages of non-toxic,environmentally friendly and efficient,high stability,excellent photocatalytic activity,and can respond to some visible light.Compared with traditional wide-bandgap photocatalysts（such as titanium dioxide,zinc oxide and tin oxide）,its pores are as active as materials such as titanium dioxide,but have a narrower band gap than these materials,which indicates that Bi₂WO₆ can be excited under visible light irradiation,which can significantly improve the utilization rate of light.At present,Bi₂WO₆as a photocatalyst has been widely used in carbon dioxide photoreduction,organic pollutant degradation,photocatalytic water cracking and other fields.The main research contents of this paper are as follows:This paper takes ofloxacin（OFL）,one of the most widely used antibiotics of fluoroquinolones,as the target pollutant,and enhances the photocatalytic activity of the nanomaterial bismuth tungstate by morphological regulation and defect construction.The specific operation is as follows:by controlling the hydrothermal solvent,adjusting its surface morphology and band structure,and studying the photocatalytic material through XRD,XPS,UV vis-DRS and other characterization technologies,the 160SBWO prepared under ethylene glycol as hydrothermal solvent,the photocatalytic material has the characteristics of greater adsorption capacity,stronger light absorption capacity,electron hole separation and faster transmission rate.The removal ability of 160SBWO with 300W xenon lamp as the light source was explored,and compared with 160HBWO prepared with hydrothermal solvent as deionized water,it showed stronger adsorption capacity and photocatalytic degradation ability of OFL under the same photocatalytic conditions.The effects of different p H,catalyst dosage,initial concentration,coexisting ions and different light sources on photocatalytic degradation were specifically studied,and the optimal p H=8,catalyst dosage was 0.5 g/L,and the optimal initial concentration was 20mg/L.At the same time,in order to further improve the performance of photocatalytic materials in the photocatalytic degradation of OFL under the condition that LED lamps are the light source.Through simple chemical etching,0.5 EBWO with oxygen vacancies was constructed,which further improved the performance of photocatalytic degradation of OFL.0.5EBWO can produce more carriers under photoexcitation,and due to the small charge transfer resistance,photogenerated carriers can migrate quickly and realize the spatial separation of carriers.0.5 EBWO has a strong adsorption capacity for OFL,which is one of the reasons for improving its photocatalytic degradation efficiency.With 30W LED light as the light source,0.5 EBWO has a stronger removal ability for OFL than160SBWO.The effects of different p H,catalyst dosage and initial concentration on photocatalytic degradation were specifically studied,and the optimal p H=8,catalyst dosage was 0.5 g/L,and the optimal initial concentration was 20 mg/L.Through capture experiments,the active species in the photocatalytic landing process were studied,and the degradation mechanism was analyzed.