Preparation Of MIL-125(Ti) Matrix Composite Material And Its Visible Light Catalytic Performance

Metal organic framework materials(MOFs)are a type of three-dimensional porous crystalline materials assembled from metal ions or metal clusters and organic ligands.Their ultra-high specific surface area,adjustable pore size,modifiable groups,unsaturated metals The active site and unique energy band structure make it have a good application prospect in the field of photocatalysis technology.Among them,MIL-125(Ti)has a stable structure,good photocatalytic performance,and is widely used in water treatment technology,but visible photocatalysis Poor performance limits its application.The introduction of AgBr with excellent photosensitivity increases the absorption of visible light by MIL-125(Ti),and the introduction of NQ-doped quantum dots(NCQDs)with fluorescence conversion to improve the visible light catalytic performance of MIL-125(Ti),based on MIL-125(Ti),NH2-MIL-125(Ti)two kinds of MOFs materials,using AgBr and NCQDs to modify them respectively,prepared AgBr/NH2-MIL-125(Ti),NCQDs/MIL-125(Ti)two The photocatalyst was characterized by XRD,SEM,XPS,BET and other characterization techniques,and Rhodamine B was used as the target pollutant to test the adsorption performance and visible light catalytic performance of the catalyst.The specific research results are as follows:Through hydrothermal method and deposition-precipitation method,AgBr/NH2-MIL-125(Ti)catalyst was successfully prepared.XRD,FTIR,XPS,UV-Vis DRS and other characterization techniques proved that AgBr was successfully introduced into NH2-MIL-125(Ti),and did not destroy the original crystal structure of NH2-MIL-125(Ti),but the crystallinity decreased.NCQDs with excellent optical properties were prepared by hydrothermal method,and NCQDs/MIL-125(Ti)catalyst was successfully synthesized by impregnation method.The characterization proved that NCQDs were 'combined with MIL-125(Ti)through N-Ti-O bond After being successfully loaded onto the MIL-125(Ti)material,the composite catalyst still has a complete crystal structure.After NH2-MIL-125(Ti)was introduced into AgBr,the adsorption performance of the catalyst decreased,and the adsorption capacity of rhodamine B was reduced from 12.63mg/g to 7.63mg/g,and the adsorption behavior of rhodamine B was more in line with Langmuir adsorption isotherm equation,the adsorption kinetics is more in line with the first-order kinetic model,the visible light photocatalytic performance is better than a single component,when the AgBr loading is 10%,the photocatalytic effect is the best,degradation of rhodamine B under visible light catalysis 2.5h,the removal rate can reach 93%,and has good stability.After MIL-125(Ti)was loaded with NCQDs,the adsorption performance of the composite catalyst decreased,and the adsorption capacity of rhodamine B decreased from 11.57mg/g to 5.02mg/g The adsorption behavior of rhodamine B is more in line with Langmuir adsorption isotherm Equation,the adsorption kinetics is more in line with the first-level kinetic model,the visible light catalytic performance is greatly improved,the removal rate of rhodamine B in 2.5h is increased from 25%of MIL-125(Ti)to 92.4%,the catalyst shows in repeated experiments Very good stability.