Study On Diatomite Supported Silver Phosphate Based Catalyst And Its Visible Light Degradation Dye Properties

In this paper,glycerol and ammonia water were used as auxiliary agents to prepare Ag₃PO₄ photocatalyst with different morphology and photocatalytic properties by hydrothermal method.At the same time,nano-silver particles were grown in situ on the surface of silver phosphate by photoreduction method to prepare Ag/Ag₃PO₄plasma photocatalyst,and composite modification of Ag₃PO₄ with diatomite earth and g-C₃N₄ to obtain Ag₃PO₄/diatomite earth,Ag/Ag₃PO₄/diatomiteearth and Ag₃PO₄/g-C₃N₄-diatomite composite.Improve the photocatalytic activity and stability of Ag₃PO₄ X-ray diffraction?XRD?,transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,ultraviolet-visible diffuse light Test methods such as spectral?DRS?and fluorescence luminescence?PL?are used to analyze the structure,morphology and optical properties of the sample.The main research contents of this paper are as follows:?1?Three synthetic methods are designed by using propylene triol and ammonia water:ammonia-water assisted hydrothermal method,alcohol-assisted hydrothermal method and hydrothermal method.The synthesized silver phosphate has better photocatalytic activity than the alcohol-assisted hydrothermal method and the hydrothermal synthesis of silver phosphate.?2?On the basis of the silver phosphate synthesized by ammonia-assisted hydrothermal method,the nano-silver particles were grown in situ on the surface of silver phosphate by photoreduction method.The photocatalytic activity of Ag/Ag₃PO₄composite catalyst was investigated under different photoreduction time.The effect of Ag/Ag₃PO₄ composite catalyst on Rhodamine B showed the best photocatalytic activity under visible light,and the mechanism of action between Ag⁰ and Ag₃PO₄ was explored.?3?The Ag₃PO₄/diatomite composite was prepared by deposition-hydrothermal method.The deposition time of Ag⁺and the content of diatomite were used as variables to investigate the light of Ag₃PO₄/diatomite composite under the combined action of the two.The results show that the Ag₃PO₄/diatomite composite exhibits the best photocatalytic activity for Rhodamine B under visible light when the content of diatomaceous earth is 20wt%and the deposition time of Ag⁺is 40 min.?4?A novel visible light-responsive Ag/Ag₃PO₄/diatomite composite was prepared by using deposition-hydrothermal-photoreduction method with diatomite earth as carrier.The crystal structure,morphology and light absorption properties were characterized by XRD,FE-SEM,EDS,TEM,UV-Vis-DRS and PL spectra.The photocatalytic activity of the sample was evaluated by degrading Rhodamine B under visiblelightirradiation.Thephotocatalyticresultsshowthat Ag/Ag₃PO₄/diatomite-20%composite has higher catalytic activity for Rhodamine B,and the rate constant of photocatalytic degradation is 4.25 times that of pure Ag₃PO₄.Moreover,the heterogeneous photocatalyst can be repeatedly used with high photocatalytic activity.Free radical trapping experiments show that the holes are the mainactivespeciesofRhodamineBphotocatalyticdegradationon Ag/Ag₃PO₄/diatomite composites.The main reason for the increase in photocatalytic activity is the synergistic effect between elemental silver,Ag₃PO₄ and diatomite.?5?A series of Ag₃PO₄/g-C₃N₄-diatomite composites were prepared by impregnation-roasting-deposition method.The photocatalytic activity and stability of Ag₃PO₄/g-C₃N₄-diatomite composite under visible light irradiation were evaluated by using Rhodamine B as a simulated pollutant.Besides,the effect of silver phosphate content on photocatalytic activity was systematically studied.The catalyst A/CD_8/2/2 was found to exhibit the highest photocatalytic activity.The degradation rate of the A/CD_8/2to Rhodamine B was as high as 98.61%under the irradiation of visible light for 21 min.The degradation rate of the A/CD_8/2/2 is 95%after recycling for three times,showing good stability and reusability.The improvement of photocatalytic activity was mainly attributed to the efficient separation of photogenerated electron-hole pairs in the silver phosphate/graphite carbon nitride-diatomite composites and the synergistic effect of adsorption/photocatalysis.