Preparation And Characterization Of Nd-Er/ZnO-TiO₂ Photocatalytic Materials Study On Photocatalytic Degradation Of Organic Phenols Compounds In Surface Water

After the world-famous Three Gorges Reservoir operation,a huge water surface of 1084 square kilometer was formed with a 175-meter normal water level height,and total storage capacity of 39 billion 300 million cubic meters.As an important water source of the country,the safety of its water quality has attracted the attention of all parties.At present,organic pollutants are the important factors that cause the safety of water quality.Among many organic pollutants,organic phenols have become one of the main pollutants in the water body because of their volatile and biological toxicity.For this reason,phenol,2-chlorophenol,m-cresol,p-nitrophenol,pentachlorophenol,2,4-Dichlorophenol and 2,4,6-Trichlorophenol have become the main pollutants in water body.Phenolic compounds because of its difficult to natural degradation,bioaccumulation,environmental persistence and strong harm due to chemical,petrochemical and other emissions exist widely in industrial wastewater,including phenol,2-chlorophenol and 2,4-dichlorophenol have been listed as one of the United States Environmental Protection Agency in the prevention and control of major pollutants of 129 objects,were also the European Union included in the priority pollutants.The paper is based on the sol-gel method to prepare a series of different doping amount and different calcining time,calcining temperature of rare earth Nd-Er/ZnO-TiO₂ photocatalyst used in the Three Gorges reservoir water environment and pollution control laboratory,in the UV and visible light irradiation.By using X ray diffraction?XRD?and surface area analyzer,laser particle analyzer,infrared spectroscopy,UV Vis diffuse reflectance UV-vis instrument,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?and other instruments for catalyst samples prepared by the crystal structure,surface structure,morphology and characteristics were characterized.The photocatalytic degradation of phenol,2-chlorophenol and 2,4-dichl-orophenol was studied by TiO₂heterogeneous photocatalysis under ultraviolet and visible light irradiation.Through characterization and degradation experiments,the results indicated that:?1?the amount of different rare earth dopants:first,we prepared ZnO-TiO₂ photocatalyst with ZnO content of 0%,5%,10%,15%and 20%respectively.And with 5%ZnO-TiO₂ as reference preparation of molar ratio of Nd/5%ZnO-TiO₂=0.5%,1%,1.5%,2%,2.5%,3%,Er/5%ZnO-TiO₂=0.5%,1%,1.5%,2%,2.5%,3%of the rare earth doped and molar ratio of Nd-Er/5%ZnO-TiO₂=0.5%+0.5%,1%+1%,0.5%+1%,1%+0.5%,1.5%+1.5%total rare earth of your.Doped photocatalytic material 2%+2%.Among them,5%samples of 1%Nd-1%Er/ZnO-TiO₂has the largest surface area and the minimum crystal size,the best photocatalytic activity?2?different calcining time:select 1%Nd-1%Er/5%ZnO-TiO₂ samples respectively in 2h 4h,6h,calcination time,calcination,8h,in the samples calcined at 2h showed higher photocatalytic activity.?3?different calcination temperature:1%Nd-1%Er/5%ZnO-TiO₂ samples were calcined at calcination temperature 450?,500?,550?,600?,650,?respectively,and the photocatalytic activity was highest at 550?.?4?photocatalytic reaction kinetics:the samples modified by ZnO and rare-earth Nd and Er showed faster photocatalytic reaction rate than pure TiO2.The sample1%Nd-1%Er/5%ZnO-TiO₂ shows the fastest photocatalytic reaction rate,and the reaction rate of each sample is faster than that of visible light under ultraviolet light.?the above experimental results have a certain reference for the degradation of organic phenols in water,and have a good application prospect.?...