Study On Diatomite Supported Silver Catalyst And Its Visible Light Catalytic Performance

In this paper,diatomite is used as the base material.In view of the problems of low added value and low utilization efficiency of diatomite materials,combined with the advantages of diatomite itself,such as large specific surface area,high porosity,light weight and low cost,various efficient photocatalysts,ssuch as Ag₃PO₄,Ag Cl,g-C₃N₄and Ag₃VO₄,are used to replace the traditional photocatalytic semiconductor.To construct a new and efficient composite photocatalytic material.The corresponding physical and image characterization and performance testing of the composite material were carried out,and the reaction mechanism of the product was explored accordingly.These works have made beneficial exploration for improving the added value of diatomite products,deepening the application of products in pollutant treatment and home decoration.Specific research contents are as follows:（1）A new type of Ag Cl/Ag₃PO₄/diatomite ternary composite was successfully prepared by microemulsion method and anion in-situ substitution method.The results of photocatalytic experiments show that the composite exhibits high photocatalytic activity and good stability after 5 cycles,and the activity loss is almost negligible.Free radical capture experiments showed that the degradation of organic dye Rh B was mainly driven by hole（h⁺）and superoxide radical（·O₂^-）.The enhanced photocatalytic activity of the composites was mainly attributed to the synergistic effect of Ag Cl,Ag₃PO₄,diatomite and in situ photoproduced Ag nanoparticles,which achieved efficient charge separation.The synergistic effect of these factors leads to the improvement of photocatalytic performance of Ag Cl/Ag₃PO₄/diatomite composites.In addition,this work provides some reference for the visible light driven photocatalyst and decorative materials industry.（2）Ag₃VO₄/diatomite composites with different proportions were synthesized by simple precipitation method.Ag₃VO₄/diatomite composite has excellent photocatalytic activity.When the proportion of Ag₃VO₄reaches 50%,the degradation rate of the composite material is the highest,which is 3.57 times that of pure Ag₃VO₄nanoparticles,and 40%of Rh B can be degraded.Capture experiments of active substances showed that the degradation of Rh B was mainly driven by holes and superoxide radicals.The significant improvement of the photocatalytic performance of Ag₃VO₄/diatomite composite can be attributed to the synergistic effect of the two materials.The good photocatalytic performance of Ag₃VO₄and the diatomite material can inhibit the rapid recombination of photogenerated electron and hole pair,which promotes the separation efficiency of photogenerated electron and hole pair in the light process.The porous structure and good adsorption property of diatomite can also further enhance the photocatalytic performance of the composites.Through the above research,it can be proposed that Ag₃VO₄/diatomite composite material has potential application in wastewater treatment.（3）The 40%-Ag₃VO₄/g-C₃N₄/diatomite ternary composites were synthesized by two-step method.The crystal morphology,microstructure,optical properties and photoelectrochemical properties of the composites were analyzed by a series of characterization analyses.Taking Cr（VI）in aqueous solution as the target pollutant,the degradation efficiency of 40%-Ag₃VO₄/g-C₃N₄/diatomite reached 70%within 60min under visible light irradiation,far exceeding the degradation efficiency of pure substances.The cyclic performance test of the composite material showed that it still had a stable degradation effect after three cycles.The degradation efficiency of the solution under different p H values was investigated.When the p H value of the solution gradually increased,the degradation efficiency gradually decreased,which was mainly caused by the different forms of Cr（VI）under different p H values.Diatomite provides a reaction place for Ag₃VO₄and g-C₃N₄,and promotes the photoreduction of Cr（VI）.This work provides a certain reference significance for the treatment of industrial heavy metal wastewater.