Study On Preparation Of MIL-101（Fe）/Mn-ZSM-5 Composite Catalyst And Degradation Of Dye Wastewater

With the rapid development of industry and society,the production and discharge of organic dye wastewater are increasing day by day,which has a greater negative impact on the human living environment and the ecological resource environment.Such dye wastewater has the characteristics of high pollutant concentration,complex composition and difficult natural degradation,and is a typical difficult to degrade organic dye wastewater.Therefore,it is of great significance to study a kind of catalytic material with high efficiency and stability,no secondary pollution and no loss of catalytic active components to treat organic dye wastewater by wet catalytic hydrogen peroxide oxidation.In this paper,MIL-101（Fe）/Mn-ZSM-5 composite catalyst was synthesized by a simple hydrothermal method using a typical azo dye acid scarlet GR as a catalytic degradation substrate,and the catalytic wet hydrogen peroxide oxidation method was used to catalyze the degradation of acid scarlet GR simulated dye wastewater.The reaction process was explored and the optimal degradation process was determined.The kinetic model and reaction mechanism were studied.1.MIL-101（Fe）/ZSM-5 and MIL-101（Fe）/Mn-ZSM-5 composite catalysts were synthesized by high temperature hydrolysis using ZSM-5 and Mn-ZSM-5molecular sieve catalysts.The samples were characterized by XRD,SEM,FT-IR,XPS and TG.The results of characterization analysis showed that both MIL-101（Fe）/ZSM-5 and MIL-101（Fe）/Mn-ZSM-5 composite catalysts showed typical octahedral shape of MIL-101（Fe）and characteristic diffraction peaks appeared at corresponding positions.The catalytic performance of MIL-101（Fe）/ZSM-5 and MIL-101（Fe）/Mn-ZSM-5 was significantly improved.The thermal stability of MIL-101（Fe）was improved by recombination with appropriate ZSM-5 and Mn-ZSM-5molecular sieves.2.The synthesized MIL-101（Fe）/Mn-ZSM-5 composite catalyst was used to degrade 1000mg/L acid scarlet GR simulated dye wastewater.The performance of the composite catalyst to degrade dye wastewater was investigated.The obtained MIL-101（Fe）/1wt%Mn（1wt%）-ZSM-5 composite catalyst has the best catalytic performance,and the decolorization rate of 25min acid scarlet GR simulated dye wastewater reaches 98.62%.3.The influencing factors of the degradation of acid scarlet GR simulated dye wastewater by MIL-101（Fe）/Mn-ZSM-5 were studied through single factor experiment.Through orthogonal experiments,the optimal degradation conditions were as follows:reaction time 25min,catalyst usage 0.20g,H₂O₂ addition amount0.7m L,reaction temperature 70℃,initial p H=3.Under the optimum conditions,the decolorization rate of acid scarlet GR solution reached 98.81%.Under the optimum process conditions,the catalyst was used to degrade other simulated dye wastewater.The results showed that the catalyst also had good catalytic performance for other simulated dye wastewater.4.Through the capture of active groups experiment,it was proved that hydroxyl radical is the main oxidation active group in the catalytic degradation reaction.The catalytic kinetic model and reaction mechanism of the composite catalytic degradation of dye wastewater by MIL-101（Fe）/Mn-ZSM-5 were further investigated.The catalytic kinetic model conforms to the pseudo-first-order kinetic model,and its kinetic equation is as follows:ln（C₀/C_t）=-2.61×10⁷×e^{-2 8.43}R¹T^7×103×C_A⁰.⁷¹⁰⁸⁸×C_B¹.¹⁰⁹⁸²×C_C^-0.87958×t...