Research On The Treatment For Artificial Dye Wastewater With Porous Material Catalyst Loaded With Iron And Cobalt

In recent years,the research on the treatment of refractory organic wastewater based on persulfate advanced oxidation has been widely concerned.Among them,cobalt based catalysts have a superior advantage for activating peroxymonosulfate（PMS）in the treatment of organic wastewater.However,cobalt-based catalysts usually suffer from serious metal leaching during the degradation processes,which might pose poor stability for catalysts and secondary contamination to the environment.The development of heterogeneous catalysts with high stability is the key to the practical application of persulfate advanced oxidation technology.In this study,FeCo-MCM-41with traditional MCM-41 materials as carrier and FeCo-MOF with metal organic framework materials MOFs as carrier were prepared and used to activate PMS for the degradation of artificial dye wastewater.The effects of different treatment conditions on the wastewater degradation were investigated to study the kinetic law and mechanism of degradation reaction.M-MCM-41（M=Fe,Co and FeCo,theoretical metal content is 2.0 wt%）was prepared by using one-pot hydrothermal method with TEOS as silicon source,Fe（NO₃）₃·9H₂O and Co（NO₃）₂·6H₂O as precursors.The characterization analyses show that M-MCM-41 materials have ordered mesoporous structure,large specific surface area and uniform pore size distribution.Fe Co-MCM-41 exhibited the combined morphological character of Fe-MCM-41 and Co-MCM-41.Fe and Co are evenly dispersed in the framework of the FeCo-MCM-41.It was found that the activity of Fe Co-MCM-41 with lower amount of metal leaching is close to that of Co-MCM-41 and is much higher than that of Fe-MCM-41 in the process of activating PMS to degrade artificial methyl orange（MO）dye wastewater.It was found that the degradation rate of MO has increased with the increase of PMS concentration,catalyst dosage and reaction temperature.The degradation efficiency of MO is significantly affected by the initial pH of MO solution and the presence of HCO₃^–.The degradation rate of MO in FeCo-MCM-41/PMS system can be improved by high temperature,ultrasound and microwave.FeCo-MCM-41 has good stability and the degradation efficiency of MO could still reach 86%after forth run.A series of radical inhibition and EPR experiments revealed that SO₄^?·and ¹O₂ generated in the Fe Co-MCM-41/PMS system are the major reactive oxygen species for the MO degradation.Therefore,it can be concluded that the degradation of MO abides by the radical and non-radical mechanisms in the FeCo-MCM-41/PMS system.The intermediate products and possible degradation paths in the process of MO degradation were studied by LC-MS。The degradation mechanism of MO in FeCo-MCM-41/PMS system was proposed based on the analyses of EPR and XPS.FeCo-MOF was prepared by using solvothermal method with H₃BTC as ligands,Fe（NO₃）₃·9H₂O and Co（NO₃）₂·6H₂O as active center precursor.The analyses of XRD and FTIR showed that FeCo-MOF has good crystallinity and the structural characteristics of MOF material.FeCo-MOF exhibits excellent catalytic performance in the process of activating PMS to degrade artificial Rhodamine B（RhB）dye wastewater.The removal efficiency of RhB can reach 98%after treatment for 30 min with room temperature.The degradation rate of RhB has been improved with the increase of PMS concentration,catalyst dosage and reaction temperature.Based on the results of radical inhibition experiments,it can be inferred that SO₄^?·and·OH generated in the FeCo-MOF/PMS system are the reactive oxygen species for the RhB degradation and SO₄^?·plays major role.FeCo-MOF has good stability and the degradation efficiency of RhB could still reach 76%after forth run.