Photocatalytic degradation of 4-chlorophenol: The effects of varying TiO{sub 2} concentration and light wavelength
- Univ. of Notre Dame, IN (United States)
The effects of TiO{sub 2} surface loading and light conditions on the photocatalyzed degradation of 4-chlorophenol (4-CP) were examined, in order to address deficiencies in previous studies in which these issues were not examined satisfactorily. It is proposed that these factors explain differences in the reported reaction intermediate concentrations. Increasing the loading of TiO{sub 2} in a slurry has little effect on the rate of 4-CP disappearance. However, the concentration of 4-chlorocatechol (4-CC), a primary degradation product decreases with increasing TiO{sub 2}. The rate of mineralization increased with increasing TiO{sub 2} concentration was more rapid under conditions of lower light intensity. Significant adsorption of 4-CC on Degussa P25 TiO{sub 2} was measured and these data are fitted well by a Langmuir isotherm. Adsorption of 4-CC accounts for most of the changes in 4-CC concentration at different TiO{sub 2} loadings. An increased proportion of surface oxidation reactions at higher TiO{sub 2} loadings and lower light intensity may explain the higher rates of mineralization in thicker slurries. The quantum yield of reaction of 4-CP increased with decreasing wavelength of light from {phi} = 0.0 1, at {lambda} = 360 nm to {phi} = 0.07, at {lambda} = 300 nm. A relationship of d[4-CP]/dt {proportional_to} I{sup 0.8} was measured. 29 refs., 7 figs., 4 tabs.
- OSTI ID:
- 563497
- Journal Information:
- Journal of Catalysis, Vol. 167, Issue 1; Other Information: PBD: 1 Apr 1997
- Country of Publication:
- United States
- Language:
- English
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