Study On The Preparation Of Composite Ag3PO4/TiO2 Heterojunction Photocatalyst And Its Performance Improvement

In the past few decades of rapid development,water pollution has become a problem of concern.The types of wastewater are diversified,and the amount of pharmaceutical wastewater accounts for a large part.Non-western(PNT)is the most typical analgesic.PNT wastewater is contained in the water environment,which seriously affects aquatic life.Environment and human health.Therefore,the development of powerful technologies to remove PNT from water has attracted worldwide attention such as flocculation,filtration,adsorption,biological contact oxidation and advanced oxidation processes(AOPs).As one of the advanced oxidation processes(AOPs),photocatalytic technology can produce reactive oxygen species(ROS).For example,hydroxyl radicals,holes and superoxide radicals are considered to be a more environmentally friendly and more worthwhile technology.In this paper,noble metal Ag nanoparticles were deposited on the Ag3PO4/P25 heterojunction structure by ultraviolet(UV)light irradiation to construct Ag/Ag3PO4/P25 double heterojunction catalyst for efficient decomposition of phenacetin(PNT).Field emission scanning electron microscopy(SEM),transmission electron microscopy(TEM),fully automated physicochemical adsorption(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Raman spectroscopy(Raman)and photoinduced Luminescence(PL)spectroscopy was used to evaluate the microstructure,chemical structure and photocatalytic activity of the synthetic catalyst material.PL spectral analysis showed that the photochemical activity of Ag3PO4/P25 was significantly enhanced due to the deposition of Ag.The mass ratio of Ag3PO4 and the effect of operating conditions on PNT degradation and catalyst stability were also investigated.The results show that Ag/Ag3PO4/P25 exhibits good photocatalytic degradation performance under UV irradiation with a catalyst concentration of 0.5g/L and a pH of 9.0.When the PNT concentration was 20 mg/L,the removal rates of PNT and TOC obtained from the Ag/Ag3PO4/P25 system were as high as 97%and 83%,respectively.After 60 minutes of conversion,the removal rate of PNT decreased from 97%to 85%between the first and last cycles.Ag/Ag3PO4/P25 with high catalytic reaction efficiency is attributed to the deposition of Ag.Ag is an electron acceptor,and Ag3PO4 has excellent electron conductivity in a heterostructure.The novel Ag/Ag3PO4/P25 composite photocatalyst can reduce the recombination of electron-hole pairs,thereby extending the lifetime of photogenerated electrons.Through ESR and free radical trap experiments,the active oxygen species which play a major role in the photocatalytic degradation of PNT by Ag/Ag3POa/P25 catalyst are:·OH,O2·-and h+.