Preparation Of G-C₃N₄ Based Composites And The Photocatalytic Degradation Of Tetracycline

The continuous development of modern industry has brought convenience to our lives,but it has also brought some problems that cannot be ignored,such as the direct discharge of industrial pollutants and improper treatment of organic pollutants,leading to serious pollution of water resources.Based on this premise,scientists want to find a safe and effective method to control the degradation of organic pollutants.Graphite like carbon nitride（g-C₃N₄）is a polymer semiconductor photocatalyst material.Compared with traditional photocatalysts such as metal oxides,metal sulfides,and metal halides,g-C₃N₄ is a non-metallic semiconductor material which has a narrow bandgap of about 2.7 e V.Because of its unique photoelectric performance,high controllability,good chemical stability,non-toxic and other characteristics,it has been widely concerned.Numerous studies have shown that g-C₃N₄ is an ideal photocatalyst material for photocatalytic treatment of water and air pollution,as well as hydrogen production.However,g-C₃N₄ has relatively narrow visible light response range,easy recombination of photogenerated charges,small specific surface area and few active site,which limit its practical application in the field of environmental photocatalysis.Therefore,this work aims to enhance the utilization of visible light and improve the photocatalytic activity of g-C₃N₄ by effectively separating photogenerated carriers and adjusting the band gap,so as to further improve its use value in daily life and production.In this work,g-C₃N₄ nanomaterials were synthesized by high-temperature calcination method,and then g-C₃N₄/Ag/Ag Br,AIS QDs/g-C₃N₄ composite materials with different loading ratios were prepared by in-situ deposition method,solvothermal method,and photoreduction assisted method.The prepared nanomaterials were characterized mainly through testing methods such as XRD,FTIR,UV-vis DRS,TEM,PL,XPS,etc.Photocurrent testing,electrochemical impedance testing,Mott-Schottky testing,and other photoelectrochemical performance tests were conducted on the materials.The results showed that a composite catalyst with retained crystal structure of g-C₃N₄ was successfully prepared.The photocatalytic activity of g-C₃N₄ and its composite samples was tested,with tetracycline hydrochloride as the target pollutant during the degradation process.Under simulated sunlight irradiation,the absorbance of the catalyst was tested at different degradation times,and the degradation efficiency was analyzed based on the changes in absorbance.Six degradation experiments were conducted on the catalyst to investigate its stability.To investigate the catalytic reaction process and its mechanism,capture agent experiments were conducted by adding sacrificial agents such as benzoquinone,n-butanol,disodium ethylenediaminetetraacetic acid,potassium persulfate,triethanolamine,ascorbic acid,and isopropanol to the reaction mixture for testing to explore their main active species.In summary,in the reaction system,g-C₃N₄ forms a heterojunction structure with other nanomaterials,and the catalytic effect of the composite sample is improved,which is superior to the pure phase g-C₃N₄ material.It has good activity in degrading organic pollutants.