| Water environment has always been an important place for human survival,but water pollution has seriously affected the living environment of human beings.Organic pollutants containing phenolic hydroxy groups are common pollutants in municipal wastewater,such as phenol-containing wastewater discharged from factories,antibiotic residues in water bodies,and some dye wastewaters.If these polluted water bodies are directly discharged without treatment,they will also cause pollution of natural water,soil,and atmospheric environment,and even endanger the health and safety of the Earth’s life.Therefore,the development of highly efficient and green water treatment technologies has become a hot topic of research.Visible-light semiconductor photocatalytic technology can directly use solar energy without additional chemical reagents to participate in the reaction.Moreover,the simple reaction device is easy to maintain with lower cost,and the pollutants can be thoroughly purified with little secondary pollution.Therefore,this technology has a good application prospects.However,since most of the single photocatalytic semiconductor materials have the lower utilization rate of the full solar energy spectrum and the poor separation capability of photocarriers,more than that there are not many studies on the mechanism of photocatalytic degradation of organic pollutants containing phenolic hydroxyls.Therefore,based on a comprehensive review of the development of semiconductor photocatalytic technology and the current status of the treatment of organic pollutants containing phenolic hydroxyl groups,we chose Bi4O5Br2 layered microspheres(Bi4O5Br2-LMs)with suitable band gap,good visible light response,and high stability as the based semiconductor material In this study,a series of three-component surface-plasmon photocatalyst Ag/AgBr/Bi4O5Br2-LMs and heterojunction photocatalyst h-BN/B4O5Br2-LMs with excellent catalytic activity under visible-light irradiation had been designed and prepared.In addition,this paper also studied the catalytic activity and mechanism of orange Ⅱ(AO7),tetracycline(TC),Acetaminophen(paracetamol,N-acetyl-para-aminophenol[APAP])and p-tert-butylphenol(PTBP)with these as-prepared composite photocatalysts under visible-light irradiation conditions.A novel ternary surface-plasmon photocatalysts Ag/AgBr/Bi4O5Br2-LMs were successfully prepared by using a facile ionic liquid-in-water(IL/W)microemulsion-mediated route and photoreduction precipitation method.The morphology and optical properties of as-prepared composite photocatalysts were characterized by different measurements(XRD,XPS,BET,FESEM,TEM etc.).Due to the plasma resonance effect of Ag and the load of visible-light photocatalyst AgBr,the absorption of visible-light by the composite photocatalysts Ag/AgBr/Bi4O5Br2-LMs have been significantly enhanced.In addition,the composite prepared by this method makes the Ag and AgBr bond tightly to Bi4O5Br2-LMs,and the constructed Z-scheme structure also effectively improves the photo-electron migration ability and the separation efficiency of photo-generated electron hole pairs,making composite photocatalysts Ag/AgBr/Bi4O5Br2-LMs have better visible-light photocatalytic activity.Through visible-light photocatalytic degradation of AO7,TC and PTBP with the series of as-prepared composite photocatalysts,indicating that 10 min Ag/AgBr/B4O5Br2-LMs had the best photocatalytic degradation activity.Therefore,in this study,the reduction deposition time of 10 min was selected as the best composite reaction time,which could reduce the energy consumption and the entire material preparation cycle of the experimental process.The highest efficiency of 10 min Ag/AgBr/Bi4O5Br2-LMs to degrade AO7(10mg/L)was up to 95%at 60min under visible-light irradiation.Based on the obtained analytic results,the main reactive species were proved to be ·O2-and h+,and the possible visible-light photocatalytic mechanism of the enhanced activity was also discussed in this study.The novel heterojunction photocatalysts h-BN/Bi4O5Br2-LMs were successfully synthesized via a facile ionic liquid-in-water(IL/W)microemulsion-mediated route.The morphology and optical properties of these composites were thoroughly characterized by different measurements(XRD,XPS,FESEM,TEM,DRS etc.).The photocatalytic activities of h-BN/Bi4O5Br2-LMs were evaluated by degradation of PTBP and APAP under visible-light irradiation,which indicated 1.0 wt%h-BN/Bi4O5Br2-LMs to be the best one.Besides,the results of photocurrent experiments showed that the photocurrent density of 1.0 wt%h-BN/Bi4O5Br2-LMs was four times higher than that of pure Bi4O5Br2-LMs due to enhanced charge transfer ability of the composite.All of the characterization revealed that the addition of h-BN can suppress the photo-induced electron-hole pair recombination of Bi4O5Br2-LMs and enhance the transaction of photo-generated carriers,so as to enhance the photocatalytic activity of the composite.Moreover,according to the results of scavenger experiments and electron paramagnetic resonance(EPR)spectra,·O2-and h+were the main reactive species in the photocatalytic process.The photocatalytic mechanism of h-BN/Bi4O5Br2-LMs was further discussed in this work and the probable degradation products were identified by GC-MS.On the basis of the frontier electron density theoretical calculation and GC-MS results,the proposed main photocatalytic degradation pathways of P TBP was conjugated addition and oxidation reactions. |
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