Preparation Of ZnO Based Composites And Their Photocatalytic Degradation Of Cefuroxime Sodium

Nowadays,the rapid development of industry has brought a series of environmental problems.In industrial waste water,liquid waste of antibiotic has prove to be a research hotspot because of its high virulence and difficult degradation.The traditional treatment of antibiotic industrial wastewater has some disadvantages,such as high cost,low efficiency,long treatment cycle,and the treated wastewater is difficult to reach the standard.As a new technology of wastewater treatment,photocatalytic oxidation is widely concerned because of its low prime cost and no secondary pollution.ZnO is an important semiconductor material,which has good photoelectric,antibacterial and chemical stability.However,its electron hole recombination rate is fast and can only absorb ultraviolet light.Therefore,it is of great significance to modify ZnO to improve its photocatalytic performance.In this study Ag/ZnO/Bi2WO6 composites were prepared by sol-gel method.Ag was introduced into ZnO to expand the range of ZnO photoresponse.Bi2WO6 was used to build heterojunction to enhance the separation efficiency of electron hole pairs.The synergistic effect of Ag and Bi2WO6 was used to improve the photocatalytic activity of ZnO,and the Ag/ZnO/Bi2WO6 three component composites with excellent properties were prepared.ZnO was prepared from zinc acetate,oxalic acid and ethylene glycol two.The morphology of ZnO was controlled by sol-gel method and polyethylene glycol 4000 as surfactant.The effects of the ratio of zinc acetate to oxalic acid,the dosage of polyethylene glycol 4000,calcination temperature and calcination time on the degradation of Rhodamine B under ZnO UV light were investigated,and the optimum preparation conditions were determined by orthogonal test.The search results showed that the calcination temperature was 550℃ the calcination time was 3.5 h,the ratio of zinc acetate to oxalic acid was 1:3,and the dosage of polyethylene glycol 4000 was 1 g.The photocatalytic effect was the best.Under the irradiation of 30W ultraviolet light,the degradation rate of Rhodamine B reached 96.88%and 98.81%respectively after 90 min and 120 min.Then,taking silver nitrate as the silver source,the photocatalytic performance of the prepared Ag/ZnO was investigated by changing the dosage of silver nitrate.Through characterization,it was found that the absorption edge of Ag/ZnO was extended to visible light,indicating that the addition of Ag can further expand the light response range of ZnO.Therefore,the photocatalytic degradation effect of Rhodamine B of Ag/ZnO samples under visible light was greatly improved.At 90 min,The degradation rate of Rhodamine B reached 98%.Finally,Bi2WO6 was prepared by sol-gel method with bismuth nitrate,citric acid and sodium tungstate as raw materials.The composite material of Ag/ZnO/Bi2WO6 three was prepared by ultrasonic bonding with Ag/ZnO.The obtained samples were characterized by XRD,SEM,EDS,XPS,FTIR,UV-Vis,DRS and p1.the crystal form,structure,element composition,valence and optical properties of the samples were analyzed,and the kinetics was analyzed.The kinetic analysis results show that the maximum K value of Ag/ZnO/Bi2WO6 sample is 0.0718,which is 9.21 times that of ZnO,indicating that Ag and Bi2WO6 have a significant effect on the modification of ZnO,and Ag/ZnO/Bi2WO6 composites have a good development prospect in the future.The Ag/ZnO/Bi2WO6 sample prepared under the optimum conditions was used for the degradation of the concentration of solution of cefuroxime.The results showed that the degradation rate of cefuroxime sodium by Ag/ZnO/Bi2WO6 reached 96.93%under the condition of 250W mercury lamp irradiation for 180 min.In addition,free radical scavenging experiments were carried out.It was concluded that OH and h+ were the main functional groups of Ag/ZnO/Bi2WO6 materials in photocatalytic reaction.Finally,the degradation conditions of cefuroxime sodium were optimized.Three factors including the initial concentration of cefuroxime sodium,the dosage of Ag/ZnO/Bi2WO6 and the initial pH of cefuroxime sodium were selected to optimize the degradation effect of cefuroxime sodium.The results showed that when the concentration of solution of cefuroxime was 5mg/L,the dosage of Ag/ZnO/Bi2WO6 was 1.25g/L,and the initial pH of cefuroxime sodium was 11,the photocatalytic degradation effect is the best.After 180 min irradiation under visible light,the degradation rate of cefuroxime sodium achieved to 99.69%.