Study On The FeOOH/BiOI Composite Photocatalyst Catalyzed Degradation Of RhB/CIP By H₂O₂

Organic wastewater such as dyes and drugs that are difficult to degrade is difficult to effectively purify using traditional water treatment technologies.Fenton reagent is popular because it generates strong oxidizing hydroxyl radicals（·OH）during use,which can degrade organic substances that are difficult to be oxidized in water,but this method needs to be used at a lower pH.The heterogeneous Fenton catalytic system based on iron oxide can broaden its pH range,but it has the problem of slow conversion of Fe³⁺to Fe²⁺.The study found that the combination of light and heterogeneous Fenton system has a synergistic catalytic effect,which can further improve the degradation efficiency of organic matter.In this project,FeOOH,a Fenton active catalyst,is combined with BiOI with strong visible light response ability to prepare a FeOOH/BiOI bifunctional catalyst to explore its photo-Fenton catalytic activity.Five ratios of FeOOH/BiOI composite materials were prepared by the water bath precipitation method,and the scanning electron microscope（SEM）,transmission electron microscope（TEM）,X-ray powder diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）Structural characterization of composite materials.The results showed that FeOOH/BiOI composite material with good crystallinity was successfully prepared,and as the amount of ferrous sulfate increased,the mass ratio of FeOOH to BiOI in the composite material increased.SEM characterization revealed that the pure FeOOH sample exhibited a curd with stacked flocs,the diameter of which was about 1μm.The pure BiOI sample is stacked into regular nanosheets through particles,and the whole is in the shape of cauliflower.The composite catalyst takes BiOI as the core,and FeOOH grows on the surface of BiOI and wraps it on the surface of BiOI in flakes,and the composite particles become more uniform.TEM characterization proved the formation of FeOOH/BiOI heterojunction structure.Through fluorescence emission spectroscopy（PL）and ultraviolet-visible diffuse reflectance spectroscopy analysis,the composite catalyst is beneficial to improve the efficiency of photo-generated electron-hole separation.The catalytic performance of five composite materials was tested,and the effects of catalyst dosage,H₂O₂ dosage,pH,and catalyst mass ratio were explored.The results show that 0.5M-FeOOH/BiOI has the best catalytic effect.When its dosage is 0.5 g/L and H₂O₂dosage is 5 mmol/L,Rh B can reach 100%degradation within 35 min.Compared with pure FeOOH,even if the H₂O₂ dosage is 100 mmol/L,the degradation efficiency of Rh B at 180 min is only 90%.Through free radical capture experiments and analysis of the concentration of iron and ferrous ions in the system,it is found that the FeOOH/BiOI visible light Fenton system significantly improves the cycle efficiency of Fe（II）/Fe（III）,and promotes the Fenton system to produce more·OH,thereby improving the system’s organic degradation ability.With CIP as the target pollutant,when the H₂O₂ dosage is3×10^-3 mol/L,90%degradation efficiency can be achieved within 80 minutes.In addition,FeOOH/BiOI also has good stability,and the removal rate of rhodamine B after three cycles is still close to 98%.Therefore,the FeOOH/BiOI semiconductor composite catalyst prepared in this topic is a promising visible light-driven Fenton The catalyst is worthy of in-depth study and extensive application.