Preparation And Modification Of FeOCl Photocatalytic Material And Its Performance On Treatment Of Rhodamine B Wastewater

Since the 21st century,with the vigorous development of industrialization,more and more dyes have been used in the food,textile,pharmaceutical and cosmetic industries,which has gradually increased the output of dye wastewater.If these wastewater are treated improperly,water pollution will be aggravated.According to statistics,the world’s annual output of dyes is as high as 900,000 tons.These dyes have the characteristics of excellent stability,high chroma,and high toxicity.After being discharged into the water body,due to the limited purification capacity of the water body,when the pollutants are integrated into the water body When the amount reaches a certain threshold,the water body cannot completely decompose it,destroying the ecological environment balance of the water body.The photocatalytic technology developed in recent years has the advantages of complete degradation of pollutants,no secondary treatment,high efficiency,cleanliness,and no selectivity to organic pollutants.FeOCl is a narrow band gap n-type Semiconductor materials（1.6 e V-1.8 e V）,with good visible light response,stable structure and unique catalytic performance,have received certain research and development in recent years.In this thesis,the thermal decomposition method is used to prepare ferric oxychloride（FeOCl）at different temperatures,and the FeOCl photo-generated electron-hole pair separation efficiency is low and the photo-generated carrier recombination rate is high.Two changes are made to FeOCl.The composite solution improves the efficiency and activity of FeOCl photocatalyst,and uses XRD,ESR,EIS,PL,SEM,photocurrent response,FT-IR,BET,XPS,UV-vis and other characterization methods for analysis and research.At the same time,the degradation of dye wastewater under visible light-rhodamine B（Rh B）is used to explore the visible light catalytic ability of the material,to capture the experiment to explore the main active groups involved in the photocatalytic reaction,and to evaluate the stability and reusability of the catalytic material by cyclic experiment According to the test results,the corresponding photocatalytic performance improvement mechanism of the heterojunction composite sample is proposed.The main contents are as follows:（1）Using FeCl₃·6H₂O as raw materials,calcining at different temperatures to prepare FeOCl photocatalysts of different crystal types,after a series of characterization,it is found that FeOCl appears as loose and neat 2D nanosheets at 250℃;UV-vis proof The band gap width of FeOCl is about 1.6 e V,and it has a strong absorption capacity between 500 nm and750 nm.The results of electrochemical experiments show that FeOCl at 250°C has good visible light response and low impedance.On this basis,the effects of various influencing factors（concentration of initial pollutants,catalyst content,p H）on the photocatalytic performance of FeOCl were explored,and the concentration of rhodamine B in the catalytic system was determined to be 4 mg/L,and the amount of catalyst used was 10 mg.（2）The FeOCl photocatalyst was prepared by thermal decomposition method,and the Ti O₂/FeOCl composite photocatalyst with different ratios was prepared by hydrothermal method.With the continuous increase of Ti O₂content,the photocatalytic degradation efficiency of Rh B first increased and then decreased.When the mass ratio of FeOCl composite is 7:3,the photocatalytic performance is the best,and the degradation efficiency of rhodamine B at 4 mg/l can reach 70%within 150 min.This is due to the different Fermi levels of Ti O₂and FeOCl.Nn heterojunction formed.（3）The FeOCl photocatalyst is prepared by partial thermal decomposition method,and is combined with Mo S₂by hydrothermal method to form different ratios of Z-type heterojunction-Mo S₂/FeOCl.When the composite ratio of Mo S₂is 40%,the photocatalytic activity increases the most.The degradation efficiency of rhodamine B at 4 mg/l in 120 min is 98%,which is 74%and 68%higher than that of Mo S₂and FeOCl monomers,respectively.The photocatalytic reaction process follows first-order kinetics,and has good stability and resistance.Light corrosive.