Preparation,antibiosis And Photocatalytic Degradation Of Pollutants Based On Tungstate Heterojunction

With the continuous progress of modern industries and massive usage of antibiotics causes the problem of water pollution.Recently,different research communities try to find a safe and effective method to degrade these antibiotics in the water environment.Very recently,zinc tungstate has been widely used in pollutant degradation as a new semiconductor catalyst in the past few decades,with effectively separate electron and hole pairs of monoclinic crystal structure,good chemical stability,and efficiency.Unfortunately,zinc tungstate has a larger bandgap and only responds to ultraviolet.Therefore,this work aims to expand its absorbance in visible light,adjust the band gap in order to further improve its application value in life and production.In this research work,ZnWO₄ nanomaterials were synthesized by hydrothermal method and high-temperature calcination method and then fabricated with Fe WO₄,Cu WO₄ and Ni WO₄,in the same way,to prepare ZnWO₄/Fe WO₄,ZnWO₄/Cu WO₄,ZnWO₄/Ni WO₄ composite photocatalytic nanomaterials with different loading.The materials were characterized by XRD,PL,SEM,XPS,UV-vis DRS.In order to analyze the photoelectric of the nanomaterials,transient photocurrent singles were also tested.The results showed that the composites have been successfully prepared without changing the crystal structure of ZnWO₄.Secondly,the photocatalytic activities of ZnWO₄ and composite samples were tested.Tetracycline hydrochloride(20mg·L^-1)was used as the pollutant,and an appropriate amount of hydrogen peroxide solution was added,and the catalytic stability of the catalyst after four degradation reactions was investigated.In order to explore the specific catalytic mechanism,the capture experiments of active species were carried out using scavengers such as methanol,triethanolamine,ascorbic acid,isopropanol,and sodium sulfate.In order to deeply study the applications of ZnWO₄ and composite samples,an antibacterial performance test experiment was investigated.In the experiment,Escherichia coli was used as the strain,and the number of colonies after adding the catalyst under dark and light conditions was compared to determine whether the strain was inactivated.The test results showed that the catalytic activity of the composite sample is better than that of the single sample.After 4 cycles,the sample can maintain a strong catalytic activity.The active group that plays the main role in the reaction process is superoxide radical（·O₂^-）,and the inactivation of Escherichia coli is better under light conditions.In summary,the addition of H₂O₂ forms a Fenton effect in the reaction system,and forms a heterojunction structure,the catalytic effect of the composite samples is better than that of ZnWO₄single material.The composite materials have good activities in degrading organic pollutants and antibacterial.