| As a new type measurement of environmental purification,the semiconductor photocatalytic technology can use sunlight effectively and has the advantage of less energy consumption,no secondary pollution and decomposing organic pollutants completely.Among many photocatalytic materials,bismuth tungstate(Bi2WO6)with the properties of high activity,effectively utilizing the sola,good stability and narrow band gap has been attracted a lot of attention of researchers and showed broad industrial application prospects.In this paper,we mainly studied the modification of Bi2WO6,the research contents are as follows:1.Zn and Cu doped bismuth tungstate photocatalysts respectively were prepared by hydrothermal method.The properties of the composite catalysts were characterized using XRD,SEM and UV-Vis DRS methods.The results showed that the prepared catalysts were orthogonal crystal phase,and the doped catalysts still maintain the original spherical flower shape with the good dispersion,and their diameters are about3~5?m.The doping of zinc and copper led to the red shift of the absorption band edge for the prepared catalyst,which broadened the response ranging from ultraviolet light to visible light of bismuth tungstate.The photocatalytic performance could be obtained from the treatment effect of Rhodamine B.After the visible light photocatalytic reaction for 120 min,when the doping contents of Zn was 10wt%,the hydrothermal reaction time was 20 h and the hydrothermal reaction temperature was180 ?,the decolorization and the COD removal rate of dye solution could reach97.11% and 72.21%,respectively.while the doping contents of Cu is 7.5wt%,the hydrothermal reaction time was 20 h,and the hydrothermal reaction temperature was180 ?,the decolorization and the COD removal rate of dye solution could reach96.53% and 70.34%,respectively.2.With the two steps hydrothermal method,BFO/Bi2WO6 composite photocatalysts were prepared successfully and their phase structure and morphology were characterized and analyzed via several different characterization measures.The optimum preparation conditions were as follows: when the loading content of BFO was 20%,the hydrothermal reaction time was 16 h,the hydrothermal reaction temperature was 180 ?,the p H value of precursor solution was 1,the prepared catalysts had higher purity and crystal lattice grew well.The surface morphology was flower-liked spherical shape with the diameter of 3-5?m,the surface of the catalyst attached to small particles uniformly,and the dispersion was good.From the Uv-Vis DRS analysis,we can obtained that the response range of visible light was broadened from 425 nm to 511 nm,which effectively enhanced the absorption intensity of bismuth tungstate to sunlight and improved the photocatalytic activity.Photocatalytic reaction was studied under visible light irradiation after 120 min,the decolorization of Rhodamine B dye solution could reach 95.79%,and the treatment effect was betterthan pure Bi2WO6.3.The optimized experiment of photocatalytic treatment conditions were carried out using Rhodamine B solution as the target,and the main influencing factors and optimum treatment conditions of BFO/Bi2WO6 catalysts in the dye solution were investigated.According the discussing conclusions,we could find that three factors played the main role in the dye treatment progress were the initial Rh B concentration,the dosage of the catalyst and the initial p H value of Rh B.Photocatalytic experiment results showed that the initial concentration of dye solution was 10mg/L,the dosage of composite catalyst was 0.25g(can be converted to 1.25g/L)and the initial p H value of dye solution was 3,the decolorization and COD removal rate was 98.64% and77.15%,respectively.The initial p H value of dye solution has the greatest influence on the photocatalytic activity of the catalysts,followed by the initial concentration of dye,and the amount of composite catalyst has the least influence on the photocatalytic activity.The composite catalyst still has good reproducibility and stability after 4cycles of recycling.4.Kinetic study of Rhodamine B simulated dye waste water treatment with BFO/Bi2WO6 composite photocatalyst was studied.The results showed that the photocatalytic oxidation degradation Rhodamine B by BFO/Bi2WO6 photocatalyst was in accordance with the first-order reaction kinetic model:Ct=C0exp(1.01742C0-0.62009Q0.53525P-1.82106t)... |
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