Preparation Of Fe Based Composites And Their Photo-fenton Performance Study

Dyes and municipal landfill leachate cause irreversible and continuous damage to the environment,and the retention of ultra-high concentrations of pollutants in the environment is a constant threat to human as well as biological health,so the development of efficient water treatment processes and the design of multifunctional catalysts are of great practical importance for the treatment of these persistent pollutants.In this thesis,a series of Fe-based composite catalysts were prepared by coupling other semiconductors with high-abundance,low-cost,low-toxicity and environmentally friendly Fe-containing solid catalysts as substrates.The photo-Fenton process was used to achieve its efficient degradation of dyes,and the best performing Fe-based composite catalysts were screened among the series of Fe-based composite catalysts for the deep treatment of municipal landfill leachate,and the main research is as follows:（1）Fe OOH was uniformly modified on nanoflower WO₃ microspheres by in situ impregnation method.The structural characterization of WO₃-Fe OOH-X was performed using X-ray diffraction spectroscopy（XRD）,Fourier transform infrared spectroscopy（FT-IR）,field emission scanning electron microscopy（FESEM）,and specific surface area pore size adsorption（BET）.The results show that the introduction of Fe OOH does not change the morphology of the pristine WO3 microspheres,Fe OOH is homogeneously grown on the WO₃ nanosheets in the form of zero-dimensional quantum dots,and Fe OOH quantum dots indirectly increase the specific surface area of nanoflower WO₃ microspheres.The photo-Fenton properties of WO₃-Fe OOH-X on methylene blue（MB）and acid red 18（AR-18）were investigated in the experiments.The results showed that within 5 min WO₃-Fe OOH-X could remove 98.69%of MB（50 mg/L）and 92.89%of AR-18（60 mg/L）,respectively,and completely degrade MB and AR-18 in the mixed dyes.In addition,WO₃-Fe OOH-3 has a high cycling stability,and WO₃-Fe OOH-3 still degrades 98.91%of MB and 98.92%of AR-18 after 5cycles.Finally,quenching experiments of reactive oxygen species show that hydroxyl radicals（·OH）play a major role in the photo-Fenton process,and holes（h⁺）play a secondary role.（2）Sr WO₄@MIL-88A（Fe）heterojunction composites were synthesized at room temperature using Fe-MOFs as substrates,and their comprehensive structural characterization was carried out to investigate their photocatalytic,Fentonian and photo-Fentonian properties for MB,respectively.The results showed that the photo-Fenton process of Sr WO₄@MIL-88A（Fe）could significantly shorten the degradation time of MB and maintain a high degradation rate.Compared with photocatalysis and Fenton alone,93.75%of MB（50 mg/L）could be degraded in 4 min.In addition,solar photo-Fenton with Sr WO₄@MIL-88A（Fe）could degrade 95%of MB within 15 min.（3）To further investigate the photo-Fenton performance of Fe-based composites for degrading complex pollutants,municipal landfill leachate was selected as the model pollutant in the experiment,and the Sr WO₄@MIL-88A（Fe）catalyst with the best decolorization performance was screened for the deep treatment of leachate through preliminary investigation of the decolorization effect of two Fe-based composites on municipal landfill leachate.The results showed that the photo-Fenton process of Sr WO₄@MIL-88A（Fe）could effectively remove the chromatic substances from the leachate,and could eliminate up to 87.19%of COD,90.23%of BOD₅,99.50%of TOP-P,80.96%of TOP-N and 81.48%of NH₃-N from the leachate.In addition,the photo-Fenton process of Sr WO₄@MIL-88A（Fe）photo-Fenton process also inactivates bacterial microorganisms in the leachate and reduces the toxicity of the water,thus reducing its epidemiological risk to humans as well as to the ecosystem.Figure[40]Table[5]Reference[124]...