Preparation Of Iron-loaded Photo-fenton Reactive Ceramic Membrane And Its Treatment Of Emerging Micropollutants

Emerging micropollutants（MPs）have attracted extensive attention because of their ubiquitous in the water environment and their harmful effects on the natural ecological environment.Such pollutants have the characteristics of various types,different properties,and difficult degradation.The conventional water treatment technology cannot effectively remove it,and there are many problems such as low efficiency,high energy consumption,and a large number of by-products.The photo Fenton ceramic membrane technology,which combines the advantages of photo Fenton oxidation technology and ceramic membrane separation technology,forms a“more miniaturized,cleaner,and energy-saving”water treatment technology,which can further improve the treatment efficacy of difficult to degrade organic pollutants,prolong the ceramic membrane cleaning cycle,and reduce the cost of water treatment.In this paper,tetracycline（TC）and 1,4-dioxane（DX）were used as model MPs,and four different morphologiesα-Fe₂O₃ photocatalyst was synthesized by solvothermal methods.And further improved photo-Fenton activity ofα-Fe₂O₃catalysts by hydrogenation modification.The photo Fenton reactive ceramic membranes（α-Fe₂O₃-CM）were prepared by a spray coating method and the effects of different preparation process conditions on the effectiveness and water flux of the degradation treatment of theα-Fe₂O₃-CM were investigated by a self-made fixed bed reactive ceramic membrane water treatment apparatus,and the degradation removal process mechanism was also investigatedThe main research contents and results of this paper are as follows:（1）Four nanostructures ofα-Fe₂O₃ photocatalyst such as truncated hexagonal bipyramid（THB）,cubic（CB）,hexagonal sheet（HS）,and spherical（RC）were prepared by solvothermal method.The catalysts were characterized,and their phase composition,morphology,structure,and optical properties were analyzed.The results were indicated that the crystalized structure was consistent with the JCPDS card ofα-Fe₂O₃.Besides,the adsorption experiment and photocatalytic activity experiment show that the four catalysts of THB,CB,HS,and RC reach the adsorption-desorption equilibrium almost within 30 min,and the maximum saturated adsorption capacity on TC was 13.17 mg/g,7.06 mg/g,6.52 mg/g and 3.95 mg/g respectively.The degradation of TC is degraded rapidly in theα-Fe₂O₃/H₂O₂/LED light Fenton system,and the degradation efficiency and degradation rate of TC reached 97.52%and 0.0969 min^-1 in the THB/H₂O₂/LED light reaction,respectively.（2）The oxygen vacancies and Fe（Ⅱ）species were successfully introduced into theα-Fe₂O₃ catalyst by hydrogenation modification.By comparing the photo-Fenton properties ofα-Fe₂O₃ before and after hydrogenation,the degradation efficiency of TC was significantly improved after hydrogenation.In the systems of H-CB/UV/H₂O₂,H-HS/UV/H₂O₂,and H-RC/UV/H₂O₂,the degradation efficiency of TC increased from59.65%,89.97%,and 87.20%to 67.34%,95.66%,and 94.71%respectively.In addition,the degradation rate increased from 0.0312 min^-1,0.0793 min^-1 and 0.0690 min^-1 to0.0404 min^-1,0.1056 min^-1 and 0.0989 min^-1,respectively.（3）Theα-Fe₂O₃-CM were successfully prepared by loadingα-Fe₂O₃ on the surface of ceramic membranes using the spray printing method.The SEM results indicated that theα-Fe₂O₃-CM surface was covered with nano photocatalystsα-Fe₂O₃,EDS further confirms the presence of Fe elements.The experimental results of membrane pure water flux show that it gradually decreases from 67.5 kg/（m²·h·k Pa）of the blank ceramic membrane（CM）to 55.8 kg/（m²·h·k Pa）with the increase of spraying layers,which is consistent with the changing trend of pore diameter,but it can still maintain good permeation flux.The photo Fenton reactive ceramic membrane system was used to degrade TC under optimal conditions.In the MF+LED light+H₂O₂ reaction system,the degradation efficiency of TC by theα-Fe₂O₃-CM-2 reached 82%,and the membrane flux remained stable in the whole reaction process.The degradation efficiency ofα-Fe₂O₃-CM-2 has did not changed in five cycles,and the permeation flux remains stable at the end of each cycle.The SEM-EDS result and iron dissolution experiment further confirm thatα-Fe₂O₃-CM-2 has long-term stability and self-cleaning function in the treatment of antibiotic wastewater by the photo-Fenton process.The results of electron paramagnetic resonance（EPR）and quenching experiments show that·O₂^-,·OH and photogenerated hole（h⁺）in the system contribute mainly to the degradation of TC.