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Degradation of Model Textile Dyes in Wastewater using Visible-Light Active Photocatalysts

Heidarpour Chakoli, Hamed | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51514 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Soltanieh, Mohammad; Vossoughi, Manouchehr; Padervand, Mohsen
  7. Abstract:
  8. Textile dyes are a major category of organic pollutants and release of them in the environment causes serious problems. Among the most commonly used methods for colored wastewater, advanced oxidation processes, especially the photocatalytic process, are rapidly developing as a new and effective solution. However, there is still a need for high-level photocatalytic activity and improvement of this process to increase removal efficiency. In this study, we have tried to provide a higher performance for color removal using carbon nitride photocatalyst. Accordingly, two approaches have been proposed to improve the removal of rhodamine b, as one of the common dyes in the textile industries. The loading of other species, such as metals and semiconductors, to enhance the absorption of light and reduce the recombination of electron-hole is one of the common ways to improve the photocatalytic process. In this study, the introducing of zero valent iron (ZVI) by retarding the recombination rate of electron-hole improved photocatalytic degaradtion. On the other hand, the use of ZVI in the acidic condition is one of the methods for transforming of persulfate to oxidizing radicals. Therefore, by introducing persulfates into a ZVI-Carbon nitride system, a significant improvement was observed for the degradation of rhodamine B. One of the reasons for increasing efficiency is the increase in the production rate of oxidizing radicals by activating persulfates from different pathways. In addition, the introduction of ZVI on a support prevents it from agglomeration, which is one of the disadvantages of direct use of ZVI. Therefore, in this research, a novel approach was presented by combining the photocatalytic process with another advanced oxidation process. ZVI in an acidic condition, in addition to activating persulfates, is capable of transforming sulfite into oxidizing radicals. Therefore, in another study, the combination of these two processes was used to degrade rhodamine B. However, the results showed that due to the low transformation rate of sulfite to oxidizing radicals, the combination of this process with the photocatalytic process is not effective in comparison with the previous proposed system
  9. Keywords:
  10. Textile Effluent ; Photocatalytic Dye Degradation ; Zero Valent Iron ; Visible Light Active Photocatalyst ; Textile Dye ; Carbon Nitride Photocatalyst

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