Study On Photocatalytic Bactericidal/dye Degradation By Precious Metal-loaded ZnO Nanofiber Film

Nanotechnology has shown its unique advantages in the direction of water treatment in the new era,among which the research and application of photocatalytic nanomaterials for sterilization and dye degradation under photocatalysis have been paid more and more attention.Nanometer zinc oxide(ZnO)is considered as a cheap and efficient photocatalyst,and ZnO nanofibers have a broad application prospect in bacteriostatic and water treatment due to their high specific surface area and special physical and chemical properties,which have higher photocatalytic activity than nanoparticles.In order to improve the engineering application limitations of nanometer ZnO particles and fiber materials in bacteriostatic and pollutant removal,nanofibers were prepared by electrostatic spinning method,and the precious metal was loaded on ZnO nanofiber materials by alcohol heat method and prepared into films,so as to overcome the problems of low catalyst reuse rate,loss with water flow and difficult recovery.The optimization process of process parameters of ZnO nanofiber thin films loaded with precious metals silver and palladium(Ag,Pd)was studied,and the properties of self-made materials in photocatalytic degradation of dyes and antibacterial were investigated.The main conclusions are as follows:(1)The preparation process and parameters of ZnO nanofibers were optimized and verified by SEM,XRD,EDS and image J.By changing the key parameters in the preparation of ZnO nanofibers,such as the configuration of precursor solution,environmental humidity and temperature,feeding speed,electric field strength and calcination process,the best preparation parameters for obtaining ZnO nanofibers with more spinning quantity,good morphology and uniform diameter distribution at the same time were determined.(2)Ag or Pd loaded ZnO nanofiber films have good photocatalytic degradation properties.The comparison of the degradation experiment of methyl orange solution found that the material prepared after the noble metal loading ZnO nanofiber can be greatly improved and the methyl orange can be completely removed within 30min.The optimal loads of Ag and Pd loaded ZnO nanofiber films were 12%(mass percentage,12%-Ag/ZnO)and 6%(6%-Pd/ZnO),respectively,and 12%-Ag/ZnO had better photocatalytic degradation and reuse stability.Then,the effects of various factors on the degradation efficiency of the material dyes were studied.At 30min before the reaction,it may belong to the activation phase of the electron hole pair of the material and have different maximum degradation rates at different initial concentrations.The degradation rate was the highest when the initial p H of methyl orange solution was 4.The higher the dosage of ZnO at the beginning of material preparation,the higher the degradation efficiency of methyl orange.The malachite green and methylene blue have good degradation effects.The results of SEM,XRD and EDS proved that Ag and Pd were successfully dispersed on the surface of ZnO nanofibers,which promoted the catalytic degradation efficiency.(3)Ag or Pd loaded ZnO nanofiber films also have good photocatalytic antibacterial properties.Through the bactericidal experiment on the escherichia coli bacteria solution(1-2)*10~6CFU/m L under the fluorescent lamp(15mw)and incandescent lamp,it was found that the Ag or Pd-loaded ZnO nanofiber film showed better antibacterial performance than the pure ZnO nanofiber film,of which the12%-Ag/ZnO nanofiber film had the strongest antibacterial performance.·OH scavenger experiments show that noble metal loaded ZnO nanofiber films play a major role in the antibacterial process is·OH;By k-b method,it is concluded that only the functional layer of the precious metal loaded ZnO nanofilm has obvious antibacterial ability.