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Novel Photocatalysis Systems: Preparation, Characterization and Kinetics Investigation of Environmental Pollutant Degradation

Mohaghegh, Neda | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 49080 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Gholami, Mohammad Reza; Tasviri, Mahboobeh
  7. Abstract:
  8. Nanophotocatalysts containing metal oxides and oxy-acids based on the nanoporous materials such as graphene, metal-organic-frameworks and carbon nano tubes were synthesized. The photocatalytic properties of the prepared samples were evaluated by the photodegradation of different pollutants in the suspension and emulsion photocatalytic systems. This study demonstrates a new kind of photocatalytic system via utilization of the superior specific properties inherent in Pickering emulsion. We designed the new photocatalytic system using a photocatalytic active component and hydrophobic conducting nanostructures to form the stabilized Pickering emulsion (Pe-bp system). The results revealed that the Pe-bp system exhibits noticeably an improvement in both efficiency and rate of AB92 photodegradation in comparison with the traditional solution-dispersed photocatalytic system. A possible mechanism explaining the origin of enhanced performance of formed nanohybrids in the Pe-bp system was also proposed by using different scavengers. In the other study, Apatite-coated Ag/AgBr/TiO2 samples based on the different TiO2 (Isolated Anatase, Isolated Rutile, Homo-p25 and OAP) was prepared by precipitation method. Ag as noble metal for forming electron/hole pairs via extending the excitation wavelength to visible light region, AgBr as a photo-sensitizer to increase the photocatalyst yield and apatite as a bioceramic material for the adsorption of pollutant were added to the multifunctional photocatalysts. SEM images and CO2 analysis for anti-microbial processes indicated that the multi-component photocatalysts can inhibit the growth of bacteria and fungi by two different mechanisms in the dark and irradiation media. In addition, oxidation of 2-propanol was also achieved under visible light irradiation using both apatite coated and uncoated samples. One can see that over each sample, the rate of acetone evolution increased with apatite coating. It should be noted that the PO43- anions in the apatite coated samples may contribute to the higher rate of acetone evolution from 2-propanol oxidation over all synthesized samples
  9. Keywords:
  10. Kinetics Study ; Apatite ; Nanoporous Materials ; Environmental Pollutant ; Poly-Functional Photocatalyst ; Photocatalytic Systmes ; Pickering Emulsion

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