Preparation Of Cu₂O/TCN Composite And Its Photocatalytic Degradation Of Tetracycline

As a kind of advanced oxidation technology(AOPs),photocatalyst technology can decompose organic matter by generating a series of strong chemically active free radicals,and shows great application potential in the removal of refractory tetracycline(TC)in water.In recent years,the issue of antibiotic residues in water bodies has attracted much attention.In order to degrade TC in water bodies,it is of great significance to develop green,efficient,and low-cost photocatalysts.In response to the above problems,this paper uses a simple liquid phase reduction method to combine cuprous oxide(Cu₂O)and hollow tubular graphite-like carbon nitride(TCN)composite photocatalyst,and designed related experiments to investigate its photocatalytic degradation performance of TC.Combined with related characterization and experimental results,we analyzed the possible mechanism of catalyst degradation of TC.The specific research content and results of this paper are as follows:(1)The composite photocatalyst of Cu₂O and TCN was prepared by liquid phase reduction method,and the morphology,structure,element valence and crystal structure of the catalyst were analyzed by common characterization methods(XRD,SEM,XPS,etc.).SEM and TEM observed that Cu₂O and TCN formed a composite structure similar to corn on the cob.There are no other impurity peaks in the XRD pattern analysis,and no new element valence peaks are observed in the XPS spectrum.The above results indicate that the composite catalyst has no other impurities,and the Cu₂O and TCN still retain their integrity after the composite.(2)With TC as the target pollutant,the most suitable photocatalytic degradation conditions are selected by the controlled variable method,and the influence of anions in the water on the degradation of TC in the system is investigated under the most suitable conditions.The results show that when the mass of TCN accounts for 10%of the total mass of the composite material,the pH of the water is 6.0,the catalyst dispersion concentration is 0.2 g/L,and the initial concentration of TC is 40mg/L,the photocatalytic degradation system can achieve the best removal effect.Under these conditions,when the photoreaction time is 160 minutes,the removal rate of tetracycline is about 90%.When carbonate ions are present in the water,the photocatalytic degradation process of the system will be inhibited.(3)With the help of EIS and PL,the reasons for the improvement of the photocatalytic activity of the composite material were explored.The energy band structure of the composite photocatalyst was analyzed and calculated through DRS and Mott-Schottky.The free radical capture test and ESR were used to determine the active species in the system.Meteorological mass spectrometry(GC-MS)was used to detect the presence of intermediate products in the photoreaction process of the system,and their possible conversion paths were deduced.The results show that the improvement of the photocatalytic activity of the composite catalyst is due to the suppression of the recombination process of photogenerated electron-hole pairs and the enhancement of the electrical conductivity of the material.In the photoreaction process,all of·OH,h⁺,and·O₂^-participate in the degradation process of TC by the catalyst.The TC is mainly degraded through hydroxylation,dehydroxylation,amide bond cleavage and demethylation.