Study On Preparation Of UiO-66 And Its Omposite Materials And Photocatalytic Degradation Of Tetracycline

With the rapid development of economy in recent years,the problem of environmental pollution has become increasingly serious.Environmental pollution has greatly affected people’s normal life.The search for a green,efficient and economical pollution control method has begun to get people’s attention.Since the 1970s,photocatalytic technology has been studied.This technology effectively uses solar energy to deal with environmental pollution,and provides a feasible choice for people to solve environmental problems with its characteristics of green energy saving and environmental protection.In this study,In2S3/UiO-66 composites were synthesized and applied to the removal of tetracycline based on the existing research results.Specific research contents are as follows:(1)A series of In2S3/UiO-66 composites were prepared by one-step solvothermal method for the first time.Firstly,the diffraction peaks,compositions,morphologies and chemical states of the composites were characterized by X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy and transmission electron microscopy.(2)The performances of In2S3/UiO-66 composites were evaluated by detecting the removal efficiency of tetracycline under dark condition(1 hour)and visible light irradiation(1 hour).The experimental results show that the tetracycline removal rates of all In2S3/UiO-66 composites are higher than those of the two prime materials(UiO-66 and In2S3).The highest removal rate of tetracycline was obtained by labeling the complex of UiO-66 and In2S3 with Zr:In as molar ratio(0.37:1),denoted as ISUO-0.37.The maximum removal rate of tetracycline was calculated to be 106.3 mg/g,which was higher than that of Ui0-66,In2S3 or other photocatalysts recorded in literature.(3)The mechanism study shows that ISUO-0.37 has higher adsorption capacity and photocatalytic activity than UiO-66 and In2S3.Although the specific surface area of ISUO-0.37(74.57 m2/g)is smaller than that of UiO-66(388.6 m2/g)or In2S3(76.36 m2/g),the former has larger pore size and adsorption sites,such as-OH,C=O,O-C-O,C=C and C-H,which may be the reason why ISUO-0.37 exhibits stronger adsorption capacity.The trapping experiments and ESR measurements show that·O2-and h+are the main causes of photodegradation of tetracycline in this work,and ISUO-0.37 produces more·O2-and h+than In2S3.Further studies on diffuse reflectance spectra show that ISUO-0.37 is better than In2S3 or UiO-66 in visible light absorption,which may be the reason why ISUO-0.37 produces more·O2-.In addition,photoluminescence emission spectra confirm that the recombination rate of photoexcited electron hole pairs in ISUO-0.37 composite is much lower than that in In2S3,which may increase h+.The results show that ISUO-0.37 has good structural stability and recyclability.