Study On The Preparation And Catalytic Performance Of Fenton-Like Catalysts Based On Metal-Organic Frameworks MIL(Fe)

Metal-organic framework materials?MOFs?are a class of inorganic-organic hybrid functional materials with periodic network structures,which formed by self-assembly of inorganic metal ions?or clusters?with organic ligands through reversible coordination bonds.Due to its advantages of high porosity,large specific surface area,adjustable channel size,abundant surface active groups and easy modification,it has a good application prospect in adsorption,catalysis,gas storage and separation,energy storage,drug delivery,sensing,biological applications and other fields,especially in catalysis.In this paper,the preparation and catalytic performance of Fenton-like catalysts based on metal-organic frameworks MIL?Fe?were studied.The specific contents are as follows:?1?A quinone-modified metal-organic framework MIL-101?Fe?was successfully prepared by a solvothermal method,and characterized by XRD,FTIR,XPS,SEM,CV and EIS.The results showed that Q has successfully bonded to MIL-101?Fe?.Compared with MIL-101?Fe?,the synthetic Q-MIL-101?Fe?had better catalytic activity,and could efficiently activate persulfate?PS?to produce free radicals to degrade the organic pollutant bisphenol A?BPA?.This was mainly due to the addition of Q,which could promote the transformation of Fe³⁺to Fe²⁺and accelerate the generation of SO₄^-?,thus accelerating the degradation of BPA.Meanwhile,the pH,catalyst dosage,oxidant concentration,temperature,etc.of the BPA degradation system activated by PS of Q-MIL-101?Fe?were studied.The optimal conditions were as follows:[Q-MIL-101?Fe?]=0.2g L^-1,[PS]=4 mmol L^-1,[BPA]=60 mg L^-1,pH=6.79,temperature=25?.Finally,cyclic experiments showed that Q-MIL-101?Fe?had good stability.?2?The four types of defective MIL-101?Fe?were synthesized by solvothermal method and adding four different defect agents?monocarboxylate defect agents:benzoic acid?HBC?,acetic acid?HAC?;dicarboxylate defect agent:oxalic acid?OA?;and tricarboxylate defect agents:citric acid?CA??.All of the samples had good catalytic activity,among them,MIL-101?Fe?-HBC was the best.As compared with dicarboxylic acid defect agents and tricarboxylic acid defect agents,monocarboxylic acid defect agents were more conducive to the generation of defects in the framwork,and increased the intrinsic activity of the catalytic center by adjusting the electronic structure.The pH,catalyst dosage and oxidant concentration of rhodamine B?RhB?degradation system activated by PS of the defective MIL-101?Fe?were studied.The optimal conditions were as follows:[MIL]=0.2g L^-1,[PS]=10 mmol L^-1,[RhB]=50 mg L^-1,pH=4.55.Finally,cyclic experiments showed that the defective MIL-101?Fe?had good stability.?3?A novel metal-organic framework material MIL-101?Fe?-Fc containing ferrocene?Fc?and defects was synthesized by a solvothermal method.Compared with MIL-101?Fe?,MIL-101?Fe?-Fc had better catalytic activity and could efficiently activate PS to generate free radicals to degrade organic pollutant RhB.The addition of Fc?COOH?2 could significantly improve the catalytic performance of the catalyst.The addition of Fc?COOH?2 not only facilitated the conversion between Fe³⁺and Fe²⁺,but also generated defects in framwork,and increased the intrinsic activity of the catalytic center by adjusting the electronic structure.Meanwhile,the influence of pH,catalyst dosage,oxidant concentration and other factors on the reaction system was investigated.The optimal conditions were as follows:[MIL]=0.2g L-1,[PS]=10 mmol L-1,[RhB]=50 mg L-1,pH=4.56.Finally,cyclic experiments showed that MIL-101?Fe?-Fc had good stability.