Preparation Of TiO₂/Ag₃PO₄ Catalyst And Its Catalytic Degradation Effect On Typical PPCPs

With the increase of the population and the improvement of living standards,the frequent detection of various drugs in the aquatic environment has caused widespread concern in the academic community and the public now.The slow accumulation of these drugs will eventually lead to irreversible changes in wildlife and humans.Therefore,in view of the safety of water bodies,it is particularly important to explore effective methods for degrading pharmaceuticals and personal care products in wastewater.Photocatalytic oxidation is a method that uses photochemical reactions of semiconductor photocatalysts to generate a large number of catalytically active substances to degrade and remove pollutants.This method is stable and harmless,so it has extremely attractive application prospects.However,TiO₂ has limited applications due to its shortcomings that it is active only under ultraviolet light,which accounts for less than 5%of solar radiation energy,and its quick recombination of electron-hole.Silver orthophosphate?Ag₃PO₄?is an excellent visible light-driven photocatalyst,but it is extremely susceptible to photocorrosion during the catalytic process.Therefore,the study of TiO₂/Ag₃PO₄ as a photocatalyst can not only expand the absorption in the visible light region,but also reduce the process of photocorrosion,while exerting the advantages of these two materials.First,prepared TiO₂ nanotubes with anodization,and then prepared TiO₂/Ag₃PO₄composite nanocatalysts useing co-precipitation.The effects of anodization time,electrolyte content,and calcination stage on the structure of composite materials were studied.Characterization and comparison of prepared TiO₂ nanotubes,Ag₃PO₄,TiO₂/Ag₃PO₄ composite nanocatalysts by means of field emission scanning electron microscope?SEM?,X-ray diffraction?XRD?,and ultraviolet-visible absorption spectroscopy?UV-Vis?,etc..When the anodizing time was reduced from 10 h to 2 h,the tube length of the nanotubes decreased from 50 um to 10 um,and the diameter of the nanotubes remained unchanged.When the water content in the electrolyte is increased from 0.5 wt%to 2.0 wt%,the order of the nanotubes is significantly increased.In the composite material calcined after co-precipitation of TiO₂ and Ag₃PO₄,the loading of Ag₃PO₄ is more,and the degradation rate of typical PPCPs?Rh B and sulpiride?is also significantly higher.Secondly,the TiO₂/Ag₃PO₄ composite nanocatalyst showed excellent performance in the degradation of sulpiride and carbamazepine.Also the TiO₂/Ag₃PO₄ composite nanocatalyst was also evaluated for the degradation of sulpiride and carbamazepine under complex conditions.Studies showed that the reaction system pH,ions and water quality have influence on the photocatalytic performance of the composite.Under neutral conditions,the degradation effect of PPCPs is significantly better than that of acid and alkaline conditions;NH₄⁺and HCO₃^-have a significant inhibitory effect on the degradation of the reaction system.Finally,the Ag⁺in the wastewater after the degradation of sulpiride by the TiO₂/Ag₃PO₄ composite nanocatalyst did not show the activation of persulfate,and the main reason for the synergistic effect of the TiO₂/Ag₃PO₄ composite nanocatalyst and persulfate is the effective separation of electron-hole pairs in the cooperative system.TiO₂/Ag₃PO₄ catalyst and persulfate have a good synergistic degradation effect on sulpiride.Under the sunlight,using 0.3 mmol/L persulfate and TiO₂/Ag₃PO₄ catalyst to synergistically degrade 10 mg/L sulpiride,the degradation rate can reach 90%in 3.0 h.In addition,factors such as pH,ions and water quality of the reaction system have an influence on the photocatalytic performance of the synergistic degradation system.