A Study of Degrading AO7 and RhB with TiO2 in Solution by Different Wavelength of Light
| Autor: | Yeoung-Sheng Wang, 王勇勝 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 TiO2 photocatalysts under UV light irradiation produce electron–hole pair (e－/h+). Then, the electron and organic pollutants would react on the TiO2 surface to decompose pollutants. In the past, many researchers study the photolysis of UV or Visible light but few discuss the effects by different light wavelengths. This research use filters to divide wave band of xenon lamp (330nm~790nm) for different wavelengths, blue (350nm~510nm), yellow (550nm~670nm) and red (610nm~750nm). The Taguchi Method and Analysis of Variance (ANOVA) were used to design the test for degrading dyes of AO7 and RhB. Using self-made STi and Degussa P25 TiO2 as photocatalysts, the STi is 100% anatase (3.2eV) which is different from P25. The Orthogonal Experimental Design was used for four factors of STi dosage, wavelengths, oxidants and oxidant concentrations. The optimal conditions in these OED-L9 (34) are determined by absorbance and TOC with variables of STi dosage (0.5g/L, 0.5g/L), wavelengths (yellow, red), oxidant (KMnO4, K2Cr2O7), oxidant concentrations (50μM, 10μM). More tests conformed the optimal result of absorbance （0.010，0.009），TOC （3.0 mg/L，2.7 mg/L）. The methold also used in dye RhB and different pH values. The optimal condition of OED-L16 (45) are determined by absorbance and TOC with variables of STi dosage (0.25g/L, 0.25g/L), wavelengths (blue, blue), oxidant (KMnO4, KMnO4), oxidant concentrations (100μM, 100μM), pH value (3，3). The optimal result are again tested 3 times for conformation, absorbance（0.054，0.052），TOC（10.5 mg/L，10.3 mg/L）, respectively. Those optimal conditions to degrade dyes of the AO7 reach 99% and the total organic carbon (TOC) to 88%, and of RhB reach 98% and the TOC approximating 60%. The optimal condition of degrading dye mixture by OED-L9(34) is determined by TOC with variables of dye mixture ration (2:1), wavelengths (blue), oxidant (KMnO4), oxidant concentrations (50μM) to approximately 60%. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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