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On the kinetics and mechanisms of photolytic/TiO2-photocatalytic degradation of substituted pyridines in aqueous solutions

Paper ID Volume ID Publish Year Pages File Format Full-Text
47544 46475 2010 10 PDF Available
Title
On the kinetics and mechanisms of photolytic/TiO2-photocatalytic degradation of substituted pyridines in aqueous solutions
Abstract

Pyridine and pyridine derivatives are extensively used for the production of pesticides, medicinal drugs, industrial solvents, dyes, rubber chemicals etc. They are encountered in their wastewaters and due to their hazardous effects on ecosystems and human health, their removal is imperative. However, the methods for their treatment need to be improved or replaced by more effective alternatives. With this in mind and following our previous work on photolytic treatment of 2-halogenated pyridines (2-HalPys), the combined photolytic/photocatalytic (TiO2 P-25) at 254 nm degradation and mineralisation of 2-chloropyridine (2-CPY), 2-fluoropyridine (2-FPY) and 2-hydroxypyridine (2-HPY), a major photolytic product of all 2-HalPys but 2-FPY are studied in a range of conditions. In order to probe into the mechanisms and factors affecting their degradation, the effects of pH, radical scavenger tert-butanol and inorganic ions, were examined. The former had a substantial impact on 2-CPY photocatalytic removal rate, which, however, remained practically unaffected by the latter. 2-CPY photocatalytic removal was faster at near neutral pH. 2-HPY degradation was faster in the presence of TiO2, low pH and in the presence of F− or SO42− anions. On the contrary, Cl− anions or the presence of tert-butanol had a pronouncedly detrimental effect on 2-HPY degradation rate. Main reaction by-products accompanying the purely photocatalytic destruction of 2-CPY and 2-FPY were identified. Complete total organic carbon removal was achieved in all cases.

Keywords
2-Chloropyridine; 2-Pyridinol; 2-Hydroxypyridine; 2-Fluoropyridine; TiO2 photocatalysis
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On the kinetics and mechanisms of photolytic/TiO2-photocatalytic degradation of substituted pyridines in aqueous solutions
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 95, Issues 1–2, 12 March 2010, Pages 100–109
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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Any Questions? feel free to contact us