Preparation Of Nano-Bi₂MoO₆-based Composite Visible Light Catalytic Material And Its Degradation Mechanism Of Iohexol

As a synthetie drug,X-ray iodine contrast agent is a commonly used agent in medicine,which is widely used to enhance the imaging observation effect of organs and blood vessels.However,this kind of drug does not react in the body,and its presence in the environment increases year by year with the direct excretion of urine.The main precursor of the by-products of iodine disinfection in water environment is the iodine contrast agent,which has potential harm to human body.Moreover,it is difficult to effectively remove it by the current conventional water treatment process.Therefore,how to effectively remove the iodine contrast agent in water is the focus of environmental scientists.In this paper,microsphere-structured Bi2MoO6 as the matrix material was combined with boron nitride(BN)and cobalt tetroxide(Co3O4)to prepare two kinds of visible photocatalytic materials,including heterojunction photocatalytic materials BN/Bi2MoO6 and Co3O4/Bi2MoO6,and the designed visible photocatalytic materials were applied to the catalytic degradation of IOH.Photocatalytic oxidation technology has been widely concerned due to its advantages of high efficiency,mild reaction conditions,stability,green and pollution-free,and has a good application prospect in the removal of organic pollutants.However,the commonly used T1O2 photocatalyst has the problem of low utilization rate of solar energy,which makes it difficult to effectively use sunlight.Therefore,researchers have developed a series of new visible photocatalytic materials,including bismuth oxide.Bismuth molybdate(Bi2MoO6)is a kind of excellent visible light catalyst,but a single semiconductor photocatalysis material for solar energy effective utilization rate is low,the spectrum of light raw carrier separation ability is poor,there is Mfor the visible light response ability is still low,high birth rate of electrons and holes in the compound light",is about the use of photocatalytic degradation of X-ray generation of iodine contrast research also not much.Bismuth nitrate and ammonium molybdate were used to synthesize bismuth molybdate with controllable morphology and uniform morphology.Bismuth molybdate was used as matrix material to prepare BN/Bi2MoO6 composite photocatalyst.Through a series of characterization methods(XRD,XPS,SEM,TEM,FT-IR,UV-Vis,etc.),the morphology and optical properties of the prepared photocatalyst were analyzed.The results also showed that the photocatalytic activity of 3.5 wt%BN/Bi2MoO6 composite semiconductor material was the best-The degradation rate of IOH reached 92%after 150 min irradiation,and the reaction rate constant reached 0.0160 min-1,which was 3.2 times higher than that of pure Bi2MoO6.The photocurrent characterization results showed that the photocurrent intensity of 3.5 wt%BN/Bi2MoO6 was 1.6 times higher than that of pure Bi2MoO6,which indicated that the photocatalytic capacity of BN/Bi2MoO6 photocatalyst was enhanced after BN loading,and the composite efficiency of electron hole pairs was reduced,further indicating that the addition of BN was conducive to improving the activity of the photocatalyst.The results of the active species quenching experiment by EPR characterization showed that the hole(h+)was the main active species of the composite semiconductor material in the visible photocatalytic degradation system.In addition,the visible light catalytic mechanism of BN/Bi2MoO6 photocatalyst was further derived,and LC-MS technology was used to identify and analyze the degradation intermediates in the catalytic system.Co3O4/Bi2MoO6 composite photocatalytic materials were synthesized by impregnating Bi2MoO6 as the matrix material,and their structure,morphology and optical properties were elucided by XRD,SEM,TEM and other analytical methods.The photocatalytic activity of Co3O4/Bi2MoO6 composite catalyst was tested with IOH as the target pollutant.The results showed that the photocatalytic activity of 10wt%Co3O4/Bi2MoO6 corriposite catalyst was the best,the degradation efficiency of IOH reached 85.6%in 180min,and the reaction rate constant was twice that of pure Bi2Mo06.Photocurrent test results of Co3O4/Bi2MoO6 composite catalyst showed that the photocurrent intensity of Co3O4/Bi2MoO6 composite catalyst was more than twice that of monomer Bi2MoO6 after the introduction of Co3O4,indicating that the migration path of electrons and holes was changed after the introduction of Co3O4,and the separation efficiency of electron hole pairs was improved.Subsequently,the possible photocatalytic mechanism of Co3O4/Bi2MoO6 composite catalyst was proposed,holes plays a leading role in the photocatalytic process.In addition,in Co3O4/Bi2MoO6 photocatalytic system joined the PMS,Co(Ⅱ)of Co3O4 as activator,activate a sulfate(PMS)produce strong oxidizer sulfate radicals(SO4-·),is used to improve the removal effect of IOH,according to the results in 40 min,iodine alcohol degradation rate reached 80%.