Preparation Of Magnetic Surface Imprinted Photocatalyst And Research On Its Behavior And Mechanism Of The Selective Recognition/Degradation Of Environmental Antibiotic Residues

The abuse of antibiotics has caused widespread presence in the environment. Although the concentration of antibiotics is low and the time is short, the inductive effect of antibiotics can cause serious harm to the environment and human body, and this leads to a series of environmental pollution and human health problems, therefore, it is urgent to remove the environmental antibiotic residues. Photocatalytic technology is a kind of advanced oxidation technology with the properties of good activity, low cost, environmental friendly, low secondary pollution, good stability etc, which has been widely used in deep treatment of environmental antibiotic residues. Among the photocatalytic materials, the organic materials (such as PPy, POPD and PEDOT) have the unique photoelectricity characteristic, and the inorganic materials (such as ZnO, TiO2 and CdS) have the characteristics of high catalytic activity, stability etc. However, the recovery of these materials is difficult and the selective removal ability is poor, which have seriously limited their applications. The introduction of magnetic material with the easy separation and recovery performance and the surface imprinting technique with the selective recognition function is a good way to solve above problems. Nevertheless, ordinary magnetic molecularly imprinted photocatalytic materials still exist problem that the photocatalytic activity and selectivity can not be simultaneously improved. Therefore, the design of magnetic surface imprinted photocatalytic materials with high photocatalytic activity and good selectivity has become the key of treatment of the environmental antibiotic residues.Accordingly, this paper constructs the organic imprinted photocatalytic system, inorganic imprinted photocatalytic system and organic-inorganic imprinted photocatalytic system, designs the novel magnetic surface imprinted photocatalytic materials, and realizes the selective recognition/degradation of the environmental antibiotic residues. A series of characterization, performance and mechanism of the magnetic surface imprinted photocatalytic materials are carried out to elucidate the design model, physical and chemical properties, photocatalytic degradation mechanism and selective recognition/degradation mechanism etc.This work mainly includes three aspects as following:1. Construction of the magnetic organic imprinted composite photocatalytic System and Research on the behavior and mechanism of selective recognition/photodegradation of antibiotics(1) CoFe2O4 is prepared by solvothermal method, through the surface imprinting technique, the surface imprinted layer is coated on the surface of CoFe204, meanwhile, Ag-POPD is introduced into the surface imprinted layer, accordingly, Ag-POPD/CoFe2O4 organic imprinted composite photocatalyst is synthesized. The morphology, structure, composition and property of Ag-POPD/CoFe2O4 organic imprinted composite photocatalyst are characterized by using XRD, XPS, FT-IR, SEM, EDS, TEM, N2 adsorption-desorption experiment, UV-vis DRS and VSM etc. Moreover, the influence of different synthetic factors on the photocatalytic degradation of ciprofloxacin and its behavior of selective photocatalytic degradation are investigated, and the mechanism of selective photocatalytic reaction is elucidated.(2) ZnFe2O4 is first prepared and used as the carrier, by means of the surface imprinting technique, the surface imprinted layer is coated on the surface of ZnFe2O4, meanwhile, Ag-PEDOT is introduced into the surface imprinted layer, accordingly, Ag-PEDOT/ZnFe2O4 organic imprinted composite photocatalyst is synthesized. The morphology, structure, composition and property of Ag-PEDOT/ZnFe2O4 organic imprinted composite photocatalyst are characterized by using XRD, XPS, FT-IR, SEM, EDS, TEM, N2 adsorption-desorption experiment, UV-vis DRS, VSM and mass spectra etc. In addition, the influence of different synthetic factors on the photocatalytic degradation of tetracycline and its behavior of selective photocatalytic degradation are investigated, the mechanism of selective photocatalytic reaction is elucidated and the intermediate degradation products are analyzed.2. Design of the magnetic inorganic imprinted composite photocatalytic System and Research on the behavior and mechanism of selective recognition/photodegradation of antibiotics(1) Hollow ring-like Fe3O4 and C/Fe3O4 are successively prepared by hydrothermal method, afterwards, ZnO/C/Fe3O4 inorganic imprinted composite photocatalyst is synthesized via the sol-gel method and surface imprinting technique. The morphology, structure, composition and property of ZnO/C/Fe3O4 inorganic imprinted composite photocatalyst are characterized by using XRD, XPS, TEM, SEM, EDS, HRTEM, HAADF-STEM, N2 adsorption-desorption experiment, UV-vis DRS, VSM and TGA etc. Moreover, the influence of different synthetic factors on the photocatalytic degradation of danofloxacin mesylate and its behavior of selective photocatalytic degradation are investigated, and the mechanism of selective photocatalytic reaction is elucidated.(2) Based on the idea of treating waste by waste, magnetic fly ash (MFAC) is selected from the solid waste and uses as the carrier, by using the sol-gel method and surface imprinting technique, pristine TiO2/MFAC is prepared, subsequently, pristine TiO2/MFAC is futher transformed into black TiO2MFAC inorganic imprinted composite photocatalyst through hydrogenation. The morphology, structure, composition and property of black TiO2/MFAC inorganic imprinted composite photocatalyst are characterized by using XRD, Raman, XPS, SEM, EDS, Element mapping, N2 adsorption-desorption experiment, UV-vis DRS and VSM etc. In addition, the influence of different synthetic factors on the photocatalytic degradation of ciprofloxacin and its behavior of selective photocatalytic degradation are investigated, and the mechanism of selective photocatalytic reaction is elucidated.3. Construction of the magnetic organic-inorganic hybrid imprinted composite photocatalytic System and Research on the behavior and mechanism of selective recognition/photodegradation of antibiotics(1) Based on the idea of treating waste by waste, fly ash cenospheres (FAC) are selected from the fly ash and use as the carrier, Fe3O4 is then introduced on the surface of FAC by coating chitosan (CTS), afterwards, TiO2 is coated on its surface via the sol-gel method, finally, POPD/TiO2/CTS@Fe3O4/FAC imprinted composite photocatalyst is synthesized by means of the surface imprinting technique and UV light-induced polymerization method. The morphology, structure, composition and property of POPD/TiO2/CTS@Fe3O4/FAC imprinted composite photocatalyst are characterized by using SEM, EDS, N2 adsorption-desorption experiment, FT-IR, element analysis, TGA, UV-vis DRS and VSM etc. Moreover, the influence of different synthetic factors on the photocatalytic degradation of enrofloxacin hydrochloride and its behavior of selective photocatalytic degradation of the single solution and binary mixed solution are investigated, and the mechanism of selective photocatalytic reaction is elucidated.(2) Fly ash cenospheres (FAC) are selected from the solid waste, Fe3O4 is then introduced on the surface of FAC by coating SiO2, subsequently, TiO2 is coated on its surface via the sol-gel method, finally, POPD/TiO2/SiO2@Fe3O4/FAC imprinted composite photocatalyst is synthesized by means of the surface imprinting technique and visible light-induced polymerization method. The morphology, structure, composition and property of POPD/TiO2/SiO2@Fe3O4/FAC imprinted composite photocatalyst are characterized by using XRD, FT-IR, N2 adsorption-desorption experiment, SEM, EDS, UV-vis DRS, VSM, XPS and mass spectra etc. Furthermore, the influence of different synthetic factors on the degradation of danofloxacin mesylate and its behavior of selective degradation are investigated, the energy level positions of TiO2 and POPD are discussed, the mechanism of selective photocatalytic reaction is elucidated and the intermediate degradation products are analyzed.(3) Fe3O4 is first loaded on the halloysite nanotubes (HNT), CdS is then loaded on its surface, by means of the the surface imprinting technique and microwave polymerization method, meanwhile, PEDOT is introduced into the surface imprinted layer, PEDOT/CdS/Fe3O4/HNT imprinted composite photocatalyst is synthesized. The morphology, structure, composition and property of PEDOT/CdS/Fe3O4/VHNT imprinted composite photocatalyst are characterized by using XRD, Raman, FT-IR, TEM, SEM, EDS, N2 adsorption-desorption experiment, UV-vis DRS, TGA, VSM, XPS and mass spectra etc. In addition, the influence of different synthetic factors on the photocatalytic degradation of danofloxacin mesylate and its behavior of selective photocatalytic degradation are investigated, the energy level positions of CdS and PEDOT are discussed, the mechanism of selective photocatalytic reaction is elucidated and the intermediate degradation products are analyzed.