Preparation Of Different Rare Earth(Er?Gd?Te)Doped Zinc Oxide Photocatalyst And Degradation Of Organic Pollutants In Water

Wood processing industry wastewater contains a large number of refractory and toxic organic pollutants,which has seriously threatened the survival and development of mankind.With the continuous growth of industrial production,it is urgent to control the pollution of wastewater.The photocatalytic technology can effectively degrade organic pollutants in the wastewater at room temperature and atmospheric pressure,and will not cause twice pollution.Compared with other catalysts,the semiconductor photocatalytic material,Zinc Oxide has good physical and chemical stability,non-toxic and harmless,low price.Doping of transition metal,alkaline earth metal and rare earth metal is an important way to adjust the band gap and crystal morphology of ZnO and improve the photocatalytic performance.Many rare earth oxides such as lanthanum oxide and neodymium oxide can effectively improve the stability and activity of the catalyst.This paper chiefly from the rare earth elements(gadolinium,terbium,erbium)to respectively by coprecipitation and sol-gel synthesis of ZnO photocatalyst a series of rare earth doped,and explore the different experimental methods at different calcination temperature,structure,morphology and activity of ZnO photocatalyst by doping different rare-earth elements and different the amount of doping conditions.Scanning electron microscopy(SEM),X-ray powder diffraction(XRD),specific surface area(BET),UV visible diffuse reflectance(UV-Vis DRS)and other techniques were used to characterize the photocatalyst.The main contents are as follows:(1)Preparation of ZnO photocatalyst for photocatalytic degradation of methylene blue coprecipitation(MB)and methyl orange(MO)as a probe reaction,preparation of different rare earth doped Zinc Oxide photocatalyst,structure,morphology and photocatalytic activity of the rare earth doped ZnO were analyzed and characterization.The results show that:with the calcination temperature and doping amount of catalyst increased,crystallinity and purity are relatively good,rare earth doped ZnO effectively caused the average grain size,specific surface area and pore size change,but a large area of the sample surface and its photocatalytic activity were relatively strong,UV-Vis DRS shows that doping of rare earth elements have little effect on the band gap of ZnO and an the absorption band has no change or slight blue shift compared with that of undoped ZnO.SEM image analysis showed that the morphology of the photocatalyst with different doping amount had a significant change.By screening the factors affecting photocatalytic system optimization,calcination temperature at 500 ?,compared to the undoped ZnO degradation rate of MB(MO)92.6%(42.4%),0.5at%Er/ZnO,0.5at%Gd/ZnO and 3at%Te/ZnO showed better photocatalytic activity under UV irradiation,2h,MB(MO)degradation rate reached 94.5%(60%),95.9%(56%),98.4%(57.7%).(2)Sol-gel preparation of ZnO photocatalyst for photocatalytic degradation of methylene blue(MB)and methyl orange(MO)as a probe reaction,the structure,morphology and photocatalytic activity of ZnO(Er?Gd?Te)doped ZnO photocatalysts were investigated.The results show that:with the increase of the calcination temperature and rare earth doping,the intensity of the diffraction peak is not obvious,there is no impurity phase.The BET data showed that the specific surface area of catalyst showed different trends.SEM analysis shows that compared with the undoped,rare earth doped Zinc Oxide has a significant effect on the morphology of the photocatalyst,UV-vis DRS shows that different doping has little effect on the band gap of ZnO.The photocatalytic activity test showed that,compared with undoped ZnO,the degradation effect of rare earth doped ZnO on methylene blue and methyl orange was improved.In three kinds of rare earth(Er?Gd?Te)doped ZnO catalyst,calcination temperature under 500?,compared to the undoped ZnO degradation rate of MB(MO)42.7%(22.1%),the photocatalytic activity of 1at%Er/ZnO,0.5at%Gd/ZnO and 1at%Te/ZnO were higher,the photocatalytic degradation rate of MB(MO)respectively 90.7%(40.3%),91.7%(49.1%),68.9%(29.5%).