Kormann, C. and Bahnemann, D. W. and Hoffmann, Michael R. (1991) Photolysis of chloroform and other organic molecules in aqueous titanium dioxide suspensions. Environmental Science and Technology, 25 (3). pp. 494-500. ISSN 0013-936X. https://resolver.caltech.edu/CaltechAUTHORS:20150813-105953063
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Abstract
The photocatalytic degradation of chloroform has been investigated in aqueous suspensions of TiO_2 over the wavelength range of 310-380 nm. A detailed reaction mechanism has been proposed in which the rate-determining step is the reaction of surface-bound *OH with adsorbed CHCl_3. A pH-stat titration technique was developed for the measurement of the rates of degradation of chlorinated hydrocarbons. The quantum efficiency (Ф = 0.56 at ⋋ = 330 nm) of the degradation of CHCl_3, was found to be inversely proportional to the square root of the incident light intensity. This relationship can be explained in terms of a direct competition between a second-order recombination of surface-bound 'OH and the rate-determining reaction of surface-bound 'OH with CHCl_3. The rates of degradation of several electron donors have been correlated with their computed surface speciation. The results of this study show that the adsorption of electron donors and acceptors to the TiO_2 surface plays a more important role in determining the rate of the photocatalytic reactions than the effect of pH-dependent Fermi-level shifts.
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| Additional Information: | © 1991 American Chemical Society. Received for review September 7,1990. Accepted October 2,1990. This research was supported by grants from the US. Environmental Protection Agency (R 813326-01-0 and R 825041-01-0). We are grateful to Drs. Dieter Gunz and German Mills for their help on this project. We appreciate the generous donation of the P25 TiO_2 by the Degussa Corp. | |||||||||
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| Issue or Number: | 3 | |||||||||
| Record Number: | CaltechAUTHORS:20150813-105953063 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20150813-105953063 | |||||||||
| Official Citation: | Photolysis of chloroform and other organic molecules in aqueous titanium dioxide suspensions C. Kormann, D. W. Bahnemann, and Michael R. Hoffmann Environmental Science & Technology 1991 25 (3), 494-500 DOI: 10.1021/es00015a018 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 59484 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Ruth Sustaita | |||||||||
| Deposited On: | 14 Aug 2015 15:44 | |||||||||
| Last Modified: | 03 Mar 2020 13:01 |
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