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Performance Enhancement of Piezoelectric Materials for Degradation of Organic Pollutants

Mahmoudi Hashemi, Alireza | 2023

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56847 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Rahman Setayesh, Shahrbanoo
  7. Abstract:
  8. In this research, piezocatalysts ceramics Bi4Ti3-xMnxO12 (x=0,0.1,0.2,0.3) were synthesized by hydrothermal method and utilized in the process of rhodamine B piezocatalytic degradation.These piezocatalysts were characterized using XRD, FE-SEM, FT-IR, DRS and PL methods. The results of XRD patterns confirmed the formation of orthorhombic crystal structure of Bi4Ti2.9Mn0.1O12 and Bi4Ti3O12 piezocatalysts. FT-IR spectroscopy confirmed the existence of chemical bonds of piezocatalysts. FE-SEM images showed the formation of Bi4Ti2.9Mn0.1O12 and Bi4Ti3O12 nanoplates. Using DRS analysis data, the absorption edge wavelength and energy gap of the synthesized piezocatalysts were obtained. Also, the results of PL analysis expressed the effective separation of electron-hole pairs in Bi4Ti2.9Mn0.1O12 piezocatalyst and the improvement of piezocatalytic activity. In the process of piezocatalytic degradation, ultrasonic vibrations were applied as an external mechanical field to the synthesized piezocatalyst. The influence of the parameters of the amount of the catalyst and the concentration of the pollutant were investigated to determine the optimal conditions of the process. Under the condition of 1g/L catalyst amount and initial pollutant concentration of 10 ppm, the efficiency of Rhodamine B dye degradation was 97% and COD removal was 52.5% in 25 minutes. Investigating the efficiency of Bi4Ti2.9Mn0.1O12 piezocatalyst in the decomposition of methyl orange dye showed a degradation efficiency of 98% in 30 minutes (catalyst amount 1g/L and initial pollutant concentration 5 ppm). The kinetics of the piezocatalytic degradation process of rhodamine B dye was investigated and the results exhibited that this process follows pseudo-first order kinetics. Specific scavengers were used to identify active radical species during the piezocatalytic degradation process, and the results showed that hydroxyl, superoxide radicals and holes are responsible for the degradation process of Rhodamine B dye. Also, the evaluation of the stability and recyclability of Bi4Ti2.9Mn0.1O12 piezocatalyst displayed that this piezocatalyst has high stability and recyclability
  9. Keywords:
  10. Piezoelectric Ceramic ; Piezocatalytic Degradation ; Rhodamine B ; Spontaneous Polarization ; Reaction Kinetics ; Organic Pollutant ; Degradation Pollutants

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