Preparation of Fe2O3/BiOBr composite photo-Fenton catalyst and its mechanism for treating organic pollutant RhB

YOU Junhua; WANG Zhiwei; LI Jingjing; LI Xuanhao

doi:10.7688/j.issn.1000-1646.2025.05.11

Abstract：[Objective]In the context of the rapid development of world industrialization,the indiscriminate discharge of dye wastewater poses a threat to the ecological environment and human life.Therefore,seeking an efficient,clean,and economical wastewater treatment method has become a research hotspot.In recent years,a photo-Fenton catalytic technology has shown great advantages in treating organic dye wastewater.BiOBr is a photocatalyst with a good visible light response,a strong light stability,and a layered structure.However,it has the problem of easy recombination of photogenerated electron-hole pairs.Monometallic irons such as Fe2O3,Fe3O4,FeOOH,and nanoscale zerovalent iron exhibit excellent performance in Fenton catalytic activity.Furthermore,their photo-Fenton catalytic activity has also been acknowledged.[Methods]Coupling BiOBr with iron-based oxides with a good Fenton catalytic activity or modifying BiOBr can effectively improve the treatment efficiency of organic wastewater.To further improve the efficiency of photo-Fenton catalytic technology in treating organic pollutants in water,a Fe2O3/BiOBr composite photo-Fenton catalyst with a Z-scheme heterojunction was prepared by precipitation and calcination methods.The composite catalyst was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM),and the photo-Fenton catalytic activity and mechanism of the composite catalyst were studied using Rhodamine B(RhB)as an organic pollutant model.[Results]The results indicate that the Fe2O3/BiOBr composite photo-Fenton catalysts all exhibit excellent photo-Fenton catalytic activities compared to the individual catalysts,and the 1.2％Fe2O3/BiOBr has the highest photo-Fenton catalytic activity(99.59％,60 min),which is about 24.8 and 3.6 times higher than those of pure Fe2O3 and BiOBr,respectively.Electrochemical testing and the radical trapping experiment show that the 1electrons in the composite catalyst flow from the conduction band of BiOBr to the valence band of Fe2O3.This achieves effective separation of photogenerated electron-hole pairs and promotes the regeneration of Fe2+,thereby improving the photo-Fenton catalytic efficiency of the composite catalyst.[Conclusion]The composite catalyst 1.2％Fe2O3/BiOBr achieves complete degradation of the organic pollutant in all five cycles of the catalytic degradation experiments with no decrease in catalytic degradation efficiency.This demonstrates that the composite catalyst possesses excellent catalytic activity and stability,which makes it a promising candidate for application as a photo-Fenton catalyst in green,economical,and efficient industrial wastewater treatment processes.