Study On The Application Of Iron-based Metal Organic Framework MIL-53(Fe) And Its Composite Materials In Photocatalysis

In recent years,with the rapid development of medicine and cosmetics industry,the production and use of drugs and personal care products（PPCPs）are increasing day by day.It is difficult for traditional wastewater treatment technology to effectively remove the drugs from wastewater,which leads to more and more drugs entering the environmental water.People attach great importance to the potential environmental risks,so it is necessary to develop effective pollutant treatment technology.At present,the main reported drug treatment technologies are adsorption,biodegradation,advanced oxidation and photocatalysis,among which photocatalysis technology has been widely studied because it is clean and pollution-free.Ketoprofen（KTP）is a kind of PPCPs,which is widely used in antiphlogistic,antipyretic,analgesic and rheumatic diseases.The amount of ketoprofen（KTP）produced and used every year in China is very large,and its impact on the environment cannot be ignored.Tetracycline（TC）is a kind of broad-spectrum antibiotics with low price,which has been widely used in livestock breeding.In2008,the export volume of tetracycline drugs alone reached 1.34*10⁷kg.The pollution of tetracycline to water and its toxic effect on ecological environment have become one of the major environmental problems faced by China and even the world.Due to its small pore size and adjustable size,iron-based metal organic framework（MIL-53（Fe））has attracted people’s attention,but its photocatalytic activity is reduced due to its narrow response range or low utilization of photo generated carriers.In order to improve the photocatalytic activity of MIL-53（Fe）,we used the coupling of MIL-53（Fe）and other semiconductor materials to construct MIL-53（Fe）based heterojunction,which can promote the separation and transfer of charge and improve the photocatalytic performance.In view of the degradation of ketoprofen in water,1T-MoS₂ and MIL-53（Fe）with rich active sites and conductivity were successfully synthesized.1T-MoS₂@MIL-53（Fe）effectively reduced the band gap of MIL-53（Fe）and improved the photocatalytic activity of iron-based metal organic framework for ketoprofen.Aiming at the degradation of tetracycline in water,silver phosphate（Ag₃PO₄）and MIL-53（Fe）were compounded to form a Z-type Ag₃PO₄/MIL-53（Fe）composite photocatalyst,which improved the effective separation and transfer of charge and enhanced its photocatalytic activity for tetracycline.The main research contents are as follows:（1）MIL-53（Fe）,MoS₂ and 1T-MoS₂@MIL-53（Fe）photocatalysts were successfully prepared by hydrothermal method.XRD,SEM,TEM and XPS were used to characterize the photocatalyst.The results showed that the photocatalyst materials were successfully prepared.The forbidden band width of the catalyst was calculated by UV-Vis DRS.The change of doping ratio has a certain influence on the catalytic performance of 1T-MoS₂@MIL-53（Fe）.When the mass of MoS₂ is 5%of the mass of MIL-53（Fe）,the prepared catalyst has the best catalytic performance.When the mass of MoS₂ is 5%of the mass of MIL-53（Fe）,ketoprofen and tetracycline were used as the research objects,and the reaction was carried out in the system of catalyst dosage of 0.2 g·L^-1 and ketoprofen concentration of 10 mg·L^-1 for 1h,The degradation rate of ketoprofen is 99%,which has a good photocatalytic degradation effect.The results of free radical capture experiment show that the main active species in the degradation process are photogenerated holes（h⁺）,a small amount of hydroxyl radicals（·OH）and superoxide radicals（O₂^-）.The degradation rate of tetracycline reached 50%when the catalyst dosage was 0.1 g·L^-1and the concentration of tetracycline was 10 mg·L^-1 for 2h.Compared with the degradation effect of ketoprofen,1T-MoS₂@MIL-53（Fe）has a good photocatalytic degradation effect on ketoprofen.（2）Ag₃PO₄/MIL-53（Fe）photocatalyst was prepared by chemical precipitation method.It was characterized by XRD,SEM,TEM and XPS.The results showed that Ag₃PO₄ and MIL-53（Fe）were successfully prepared to form composite photocatalysis materials.The change of preparation conditions would affect the catalytic performance of Ag₃PO₄/MIL-53（Fe）catalyst.When the mass ratio of Ag₃PO₄/MIL-53（Fe）was 1:5,ketoprofen and tetracycline were used as the research objects.The amount of catalyst was 0.4 g·L^-1,and the concentration of ketoprofen was 10 mg·L^-1,The degradation rate of ketoprofen reached 90%for 4 hours.Compared with pure MIL-53（Fe）and pure Ag₃PO₄,Ag₃PO₄/MIL-53（Fe）had a better photocatalytic effect on ketoprofen.The experimental results of free radical capture show that the main active species in the degradation process are photogenerated holes（h⁺）,a small amount of hydroxyl radicals（·OH）and superoxide radicals（O₂^-）.In the system of 0.4 g·L^-1 catalyst and 10 mg·L^-1 tetracycline concentration for 2h,the degradation rate of tetracycline is 90%.Compared with the degradation effect of ketoprofen,Ag₃PO₄/MIL-53（Fe）has a good photocatalytic degradation effect on tetracycline.