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Synthesis and Characterization of Ferrite Nanocomposites and the Role of Graphene Oxide in Their Photocatalytic Activities in Degradation of Contaminants

Kaveh, Reyhaneh | 2019

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52138 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagherzadeh, Mojtaba
  7. Abstract:
  8. The main aim of present thesis is to synthesis and characterize of ferrite nanocomposites as a new generation phtocalyst and their application in degradation of various types of environmental pollutants in different irradiation time and dark conditions. Ferrites have been used anchored to carbon allotropes such as graphene oxide and carbon nanotubes, in order to improve their photocalytic activity as well as phase structure, textural and optical properties. Firstly, a new SnS2-BiFeO3/rGO nanocomposite has been prepared to increase the visible-light-responsive photodegradation of organic dyes such as cationic methylene blue (MB) and anionic methyl orange (MO). The obtained results showed that SnS2, BiFeO3, SnS2(1.5)-BiFeO3 and SnS2(1.5)-BiFeO3/rGO (0.15) degraded 41%, 47%, 86% and 98% of MB after 90 min visible light irradiation. Also SnS2, BiFeO3, SnS2(1.5)-BiFeO3 and SnS2(1.5)-BiFeO3/rGO (0.15) nanocomposite degraded 41%, 43%, 85% and 96% of MO during the same time of irradiation. In the second step, two other new rGO/CaFe2O4/Ag3PO4 and rGO/MgFe2O4/Ag3PO4 nanocomposites were successfully synthesized via solvothermal methods. The photocatalytic performance of these composites were evaluated by photo-degradation of 4-chlorophenol (4-CP), MB and MO in water under visible-light irradiation. The sample of rGO/CaFe2O4/Ag3PO4 exhibited the wonderful visible light photocatalytic activity compared with other synthesized samples such as pure Ag3PO4 and MFe2O4 (M=Ca, Mg) nanoparticles. For the next step, CdS-NiFe2O4/rGO nanocomposite has prepared by a facile method and the synergistic effect of GO content on the photoactivity of the CdS-NiFe2O4 nanocomposite was investigated. The results indicated that CdS-NiFe2O4/rGO nanocomposite had higher photocatalytic activity than neat NiFe2O4 and CdS nanoparticles toward the degradation of MB under visible lightirradiation. In the last step, a new Pd-rGO/CNT/CaFe2O4 nanocomposite has been successfully synthesized. The role of rGO/CNT nanoparticles has been investigated in improving the photocatalytic activity of this nanocomposite. Moreover, the role of palladium nanoparticles in increasing efficiency of photocatalytic activity was investigated. Finally, the mechanism and kinetics of degradation of pollutants in the presence of all prepared photocatalysts were studied. The value of Kapp for the optimized photocatalyst (Pd-rGO/CNT/CaFe2O4 (40%)) is 0.0548 min-1 that is higher than other samples such as CaFe2O4 under the same conditions
  9. Keywords:
  10. Photocatalyst ; Ferrite Nanocomposite ; Graphene Oxide ; Composite ; Visible Light ; Degradation Pollutants

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