Synthesis Of Zirconium-based Metal-organic Materials And Their Photocatalytic Degradation And Fluorescence Detection Performance

In order to effectively deal with the problem of water environment treatment,it is very important to develop efficient removal and detection technology of environmental pollutants.The sensing technology based on the change of material luminescence and photocatalytic degradation technology is the technical means of effective removal and detection of environmental pollutants,which has many advantages such as simple operation,green energy saving,fast and efficient.Metal-organic material(MOM)is a class of organic-inorganic hybrid materials.It is of great application prospect of zirconium based MOM in removing and detecting environmental pollutants because of the advantages such as porosity,rich luminescence properties,easily functionalization and high hydrothermal and chemical stability.Based on this,this paper focused on the two representative branches of MOM,the metal-organic framework(MOF)with extended structure and the metal-organic cage(MOC)with discrete structure and studied the application of zirconium based MOF and zirconium based MOC in photocatalytic degradation and fluorescence detection of environmental pollutants in water.The main research contents are as follows:(1)2D/2D g-C₃N₄/Zr-MOL nanocomposites were prepared by in-situ growth of two-dimensional Zr-MOL on g-C₃N₄by using g-C₃N₄nanosheets as templates through microwave-assisted solvothermal method and studied the performance in photocatalytic degradation of dyes and antibiotics.The results showed that the optimal ratio of the composite material showed significantly enhanced photocatalytic activity,whose photocatalytic degradation efficiency of crystal violet(CV),norfloxacin(NFX)and theophylline(THEO)of 10 mg/L can reach more than 90%under visible light irradiation for 60 minutes with only 0.1 g/L dosage.Moreover,the performance and structure of the composite remained stable after five cycles.Further results showed that the intimate interfacial contact between g-C₃N₄and Zr-MOL constructed a built-in electric field,which accelerated the separation and migration of photogenerated carriers,promoted the generation of active species such as ¹O₂and h⁺,and finally improved the photocatalytic degradation efficiency.(2)A novel hydroxyl-functionalized zirconium based metal-organic cage(Zr-MOC)with V₄E₆topology was constructed by one-pot method,and its application in the detection of pharmaceutical and personal care products(PPCPs)and dichromate was studied.Zr-MOC exhibited ligand-based luminescence.Furthermore,the photoluminescence of Zr-MOC solutions with different concentrations was modulated by possible intramolecular/intermolecular interactions of hydroxyl hydrogen on the ligand.Zr-MOC selectively detected trace sulfamethazine(SMZ),furantoin(NFT),furacillin(NFZ)and dichromate(Cr₂O₇^2-)in the liquid phase with high fluorescence quenching sensitivity through fluorescence quenching effect,and the low of detection was 0.747?M,0.561?M,0.622?M and 1.412?M,respectively.Moreover,Zr-MOC also has excellent selectivity under the interference of co-existing environmental pollutants.Further studies showed that the efficient fluorescence quenching of Zr-MOC was mainly due to the synergistic effect of electron transfer and light energy competition between Zr-MOC and analytes.