Study On Synthesis Of Fe-MOFs By Microwave-assisted With Chemical Modulators And Activate Persulfate On Refractory Organic Pollutants Treatment In Water

Advanced oxidation processes based on sulfate radical（SR-AOPs）possess several advantages such as simple operation,mild conditions and excellent performance during the process of treating typical refractory contaminants.Then SR-AOPs become the ideal option for water pollution control.As heterogenous catalysis process is considered as the promising method for SR-AOPs,novel catalysts including metal organic frameworks（MOFs）have been synthesized.MOFs are proved as the robust catalysts in SR-AOPs for their designable structure and numerous catalytic sites.Since the traditional synthesis method of MOFs consumes hazardous chemical reagents under relatively high temperature and pressure with low yield,the application of MOFs has been limited to laboratory without any further expansion.Overall,in this study the Fe-MOFs were synthesized under microwave assisted with modulation which met the requirement of green and macro synthesis.Furthermore,the synthesized samples were applied as catalysts for SR-AOPs to degrade some typical pollutants.Firstly,some weak acid or base reagents were used as modulators to prepare Fe-MOFs-MW under microwave assisted.The effect of types and dosages for modulators on crystal structure and yield was systematically studied.Dual modulation effect was found when CH₃COONH₄acted as the modulator.There were much more defects built which dramatically enhanced catalytic performance.It was found that 7.5mmol CH₃COONH₄ could considerably increase the yield with synthesis period reduced to 90 min.Fe-MOFs-MW-D synthesized by optimal condition performed fantastic during OG degradation by activating PS.The stoichiometric efficiency（RSE）was relatively high with desirable recycling performance.OG degradation pathway was deducted through DFT analysis and GC-MS detection.Besides,activation model was also proposed via EPR and XPS methods.The circulation of Fe CUS and S₂O₈^2-was found in the degradation system which promoted recycling catalytic performance.On the basis of the previous research,Fe₃O₄@Fe-MOFs-MW composite was successfully synthesized by one-pot method with Na OH as modulator.Then the novel composite catalyst was applied in SR-AOPs to degrade sulfamethoxazole（SMX）.Through regulating dosage of Na OH,the effect on crystal structure and magnetic intensity was figured out that Na OH played a role in modulating the component ratio in prepared samples.The ratio of the organic ligand（H₃BTC）and precursor（Fe SO₄）could affect coordination model of catalysts.Furthermore,accelerating effect of Na OH on nucleation growth was confirmed by crystal growth model.Ideal synthesis method for Fe₃O₄@Fe-MOFs-MW was found that 0.8 m M Na OH with the ratio of Fe SO₄ and H₃BTC remaining 1:1 could dramatically expand the yield.The unique morphology which similar to the hollow bar could provide much more catalytic sites for PS activation.Besides,synergistic effect found in the composite catalyst was also helpful for SMX degradation.Response surface method（RSM）was used to analyze the influence of water matrix on degradation performance.An accurate and reliable prediction model was established for further indication.Moreover,excellent cyclic catalytic performance of the composites was confirmed by relatively high SMX removal during recycling experiments.Finally,the activation mechanism of Fe₃O₄@Fe-MOFs-MW/PS system was proposed via various characterization methods.