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Synthesis of Mof-Based Magnetic Nanocomposites and their Capability for Organic Dye Degradation in Water Via Photocatalysis Process

Bagherzadeh Hosseini, Behnam | 2022

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 55100 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Kazemeini, Mohammad; Mahmoodi, Niyaz Mohammad
  7. Abstract:
  8. Photocatalytic as well as photo-Fenton-like processes are promising and ideal technologies for using solar energy to regenerate energy as well as regenerate and revitalize the environment. In fact, photocatalytic processes are one of the most important chemical methods to reduce energy and environmental crises by converting endless solar energy into pure chemical potential. Photocatalytic processes and photocatalysts based on metal-organic frameworks (MOFs) have attracted special attention in recent years due to their excellent and unique properties such as adjustable structure and optical properties. In fact, metal-organic frameworks, as a group of newly emerged crystalline porous materials, have provided an advanced platform for the development of catalysts for the photocatalytic degradation of a variety of organic pollutants in wastewater and industrial and domestic waste. But an important issue in the use of composite structures of metal-organic frameworks and their hybrid combinations with other active materials with photocatalytic properties, is the separation of photocatalysts from the reaction mixture at the end of the process. One of the key and practical solutions to solve this problem is to create magnetic properties in composites based on metal-organic frameworks. In this thesis, two categories of magnetic composites based on different metal-organic frameworks have been synthesized and prepared. In the first part of this thesis, the metal-organic framework of MIL-53(Fe) was synthesized by solvothermal method. Then magnetic cobalt ferrite nanoparticles (CoFe2O4) were prepared by hydrothermal method. In the next step, by loading different amounts of CoFe2O4 magnetic nanoparticles (0.05, 0.1 and 0.2 g), three magnetic composites of MIL-53(Fe) were synthesized with cobalt ferrite nanoparticles by solvothermal method. In the second part of this thesis, new binary and ternary magnetic composites based on MIL-101(Fe) were prepared. Therefore, graphene oxide (GO) was first prepared using the modified Hummer method. Then, hydrothermal method was used to synthesize CoFe2O4 magnetic nanoparticles. MIL-101(Fe) metal-organic framework and MIL/Co, MIL/GO and CoFe2O4/GO binary composites as well as MIL/Co/(3%)GO and MIL/Co/(7%)GO ternary composites were prepared using the solvothermal method. After synthesis, the physical and chemical properties of the catalysts are determined by XRD, FESEM, TEM, EDX dot-mapping, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses. The use of XRD analysis confirmed the presence of the desired crystallographic properties in the samples. Morphological characteristics, structure and surface texture of the samples were evaluated using FESEM and TEM analyses. The homogeneous distribution and uniform dispersion of different elements on the surface of the samples can be understood through EDX images and their point micrographs. Also, using BET-BJH analysis, specific surface area and other porous structure characteristics of the samples were investigated. The presence of very good magnetic properties in the samples was also confirmed by VSM analysis. In the next step, the performance of the samples in the process of photocatalytic degradation and photo-Fenton-like degradation of organic pollutants under visible light was investigated. In this regard, the photocatalytic degradation rate of DR23 molecules after 80 minutes for CoFe2O4, MIL-53(Fe), MIL-53(Fe)/0.05gCoFe2O4, MIL-53(Fe)/0.1gCoFe2O4 and MIL-53(Fe)/0.2gCoFe2O4 was determined to be 60, 99.20, 99.20, 99.35 and 97.76%, respectively. Also, the rate of photo-Fenton-like degradation of DtR-23 and ReR-198 pollutants using MIL/ Co/(3%)GO sample after 70 minutes of visible light irradiation was 99.93% and 99.65%, respectively.
  9. Keywords:
  10. Photocatalytic Degradation ; Organic Pollutant ; Metal-Organic Framework ; Soft Magnetic Composites (SMC) ; MIL-101 (Fe)Composite ; Photo-Fenton-Like Degradation ; MIL-53 (Fe)Composite ; Visible Light

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