Martin, Scot T. and Lee, Albert T. and Hoffmann, Michael R. (1995) Chemical mechanism of inorganic oxidants in the TiO_2/UV process: increased rates of degradation of chlorinated hydrocarbons. Environmental Science and Technology, 29 (10). pp. 2567-2573. ISSN 0013-936X. doi:10.1021/es00010a017. https://resolver.caltech.edu/CaltechAUTHORS:20150810-083411329
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Abstract
Particulate suspensions of TiO_2 irradiated with UV light at wavelengths shorter than 385 nm catalyze the autooxidation of chlorinated hydrocarbons such as 4-chlorophenol (4-CP). The addition of oxyanion oxidants such as CIO_2^-, CIO_3^-, IO_4^-, S_2O_8^(2-), and BrO_3^- increases the rate of photodegradation of 4-CP in the following order: CIO_2^- > IO_4^- > BrO_3^- > CIO_3^-. In the absence of TiO_2, CIO_3^- shows no photoreactivity toward 4-CP, while HSO_5^- and MnO_4^- exhibit rapid thermal reactivity with 4-CP. BrO_3^- appears to increase photoreactivity by scavenging conduction-band electrons and reducing charge-carrier recombination. With CIO_3^- as an oxidant, the degradation of 4-CP appears to follow three concurrent pathways. Kinetic equations for the rate of degradation of 4-CP as a function of [4-CP], [CIO_3^-], and [O_2] and of the light intensity are derived from a proposed mechanism.
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| Additional Information: | © 1995 American Chemical Society. Received for review February 7, 1995. Revised manuscript received June 1, 1995. Accepted July 6, 1995. We are grateful to ARPA and ONR {NAV 5 HFMN N0001492J1901} for financial support. Drs. Ira Skurnick and Harold Gund provided generous support and encouragement. S. T .M. is supported by a National Defense Science and Engineering Graduate Fellowship. A.T.L. is the recipient of a Summer Undergraduate Research Fellowship from Caltech. Wonyong Choi, Peter Green, Nicole Peill, and Janet Kesselman provided valuable support and stimulating discussion. | |||||||||
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| Issue or Number: | 10 | |||||||||
| DOI: | 10.1021/es00010a017 | |||||||||
| Record Number: | CaltechAUTHORS:20150810-083411329 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20150810-083411329 | |||||||||
| Official Citation: | Chemical mechanism of inorganic oxidants in the TiO2/UV process: increased rates of degradation of chlorinated hydrocarbons Scot T. Martin, Albert T. Lee, and Michael R. Hoffmann Environmental Science & Technology 1995 29 (10), 2567-2573 DOI: 10.1021/es00010a017 | |||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 59332 | |||||||||
| Collection: | CaltechAUTHORS | |||||||||
| Deposited By: | Ruth Sustaita | |||||||||
| Deposited On: | 10 Aug 2015 18:23 | |||||||||
| Last Modified: | 10 Nov 2021 22:18 |
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