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Investigation of Nano-Semiconductors for Decontamination of Pollutants under Solar Light

Bararpour, Toufigh | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48557 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Soltanieh, Mohammad; Vossoughi, Manouchehr; Feilizadeh, Mehrzad
  7. Abstract:
  8. Photocatalytic degradation is one of the developing modern and effective methods for decontamination of hazardous pollutants of chemical industrial wastewater. For this purpose, in this research, the efficiency of the photocatalytic process in degradation of Cortisone Acetate is investigated under solar light irradiation, and the effect of two useful oxidants, potassium persulfate (PDS) and potassium proxy mono sulfate (PMS), on the degradation efficiency is examined. At first, the single effect of these two oxidants, and then their interaction effects with the photocatalyst (TiO2-P25) and solution pH by analytical analysis and with the help of Response Surface Methodology (RSM) and Artificial Neural Network models were studied. Results obtained from these two models were compared, and it was revealed that the accuracy of the ANN model in prediction of the behavior of the systems (with their really complex interaction effects) is more than the other one. So this model was utilized to investigate the effect of the parameters. The optimum conditions for these parameters appeared to be 405.4 mg/l, 271.2 mg/l and 240.4 mg/l for TiO2-P25 loading, PDS concentration and PMS concentration, respectively and the maximum degradation efficiency at this point approached to 93.5% after 30 min of solar light irradiation. After this experiment, the efficacy of the solution pH, as an effective parameter on the degradation efficiency, was studied on the operation of TiO2-P25, PDS and PMS. In the first experiment, the simultaneous effect of the solution pH and catalyst loading was examined. In this system, the degradation efficiency reached to its maximum value in pH = 7.8. The maximum degradation efficiency of Cortisone Acetate in the presence of PMS and PDS occurs in the pH values of 3.75 and 2.3, respectively. By increasing the solution pH, the degradation efficiency reduces due to a decrease in the concentration of the active species (sulfate radicals) in the reaction mixture. So acidic environment is the best condition for increasing oxidants efficiency
  9. Keywords:
  10. Solar Radiation ; Semiconductors ; Photocatalytic Purification ; Oxidizers ; Cortisone Acetate

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