fulltext.study @t Gmail

Degradation intermediates and reaction pathway of pyraclostrobin with TiO2 photocatalysis

Paper ID Volume ID Publish Year Pages File Format Full-Text
46431 46439 2012 9 PDF Available
Title
Degradation intermediates and reaction pathway of pyraclostrobin with TiO2 photocatalysis
Abstract

The present study deals with the photocatalytic degradation of the strobilurin pyraclostrobin in the presence of titanium dioxide (TiO2) as a photocatalyst and UV light irradiation. The obtained results show a complete degradation of pyraclostrobin at pH 6.2, temperature at 20 ± 1 °C and 0.5 g L−1 of catalyst after 60 min irradiation. Photodegradation of pyraclostrobin exhibited pseudo-first-order reaction kinetics. The rate of photodecomposition of pyraclostrobin was measured using high performance liquid chromatography–diode array detector (HPLC–DAD). The effect of solution pH in the 2–10 range was investigated as well as the reaction intermediates formed during degradation. To obtain a better understanding of the mechanistic details of this TiO2-assisted photodegradation of pyraclostrobin with UV-irradiation, the intermediates of the processes were concentrated, separated and identified by the solid-phase extraction (SPE) and liquid chromatography/mass spectrometry (LC–MS/MS) technique. The probable photodegradation pathways were proposed and discussed. The main steps involved: hydroxylation of the aromatic rings (chloro-phenyl, phenyl and pyrazol) followed by the loss of the N-methoxy group, substitution of chloride atom by a hydroxyl group, rupture of the pyrazol and phenyl bond and the scission of the oxygen and pyrazol bond.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pyraclostrobin was totally degraded in an aqueous TiO2 suspension in the dark after 60 min. ► The rate constant for the reaction of pyraclostrobin was calculated as kobs = 1.4 × 10−2 min−1. ► The photodegradation rate was found to increase along with decreasing pH. ► Eleven intermediates were identified by HPLC–APCI–MS/MS. ► A mechanism of degradation has been tentatively proposed.

Keywords
Pyraclostrobin degradation; Photocatalysis; TiO2; Intermediate products; HPLC–MS/MS
First Page Preview
Degradation intermediates and reaction pathway of pyraclostrobin with TiO2 photocatalysis
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
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 115–116, 5 April 2012, Pages 285–293
Authors
, , , , , ,
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
Online Support
Any Questions? feel free to contact us