Abstract
Heterogeneous photocatalysed reaction of three selected pesticide derivatives such as propham (1), propachlor (2) and tebuthiuron (3) has been investigated in aqueous suspensions of titanium dioxide by monitoring the change in substrate concentration employing UV Spectroscopic analysis and depletion in Total Organic Carbon (TOC) content as a function of irradiation time. The degradation kinetics was studied under different conditions such as pH, catalyst concentration, substrate concentration, different types of TiO2 and in the presence of electron acceptors such as hydrogen peroxide (H 2O2), potassium bromate (KBrO3) and ammonium persulphate (NH4)2S2O8 besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with other photocatalysts. The pesticide derivative propham (1) was found to degrade faster as compared to propachlor (2) and tebuthiuron (3). An attempt has also been made to identify the products formed during the photooxidation process through GC/MS analysis technique. All the model pollutants showed the formation of several intermediate products, which were identified on the basis of molecular ion and mass spectrometric fragmentation pattern. A probable mechanism for the formation of the products has been proposed.
| Original language | English |
|---|---|
| Pages (from-to) | 457-468 |
| Number of pages | 12 |
| Journal | Chemosphere |
| Volume | 61 |
| Issue number | 4 |
| DOIs | |
| State | Published - Oct 2005 |
| Externally published | Yes |
Bibliographical note
Funding Information:Financial support from Alexander von Humboldt Stiftung, Bonn, Germany (Post Doctoral Fellowship to Dr. M. Muneer for 3 months under follow-up programme) and Department of Science and Technology, New Delhi, India is gratefully acknowledged. Total Organic Carbon (TOC) Analyzer used for the analysis of the samples was a gift instrument from the Alexander von Humboldt Foundation, Bonn, Germany.
Keywords
- Photocatalysis
- Propachlor
- Propham
- Semiconductor
- Tebuthiuron
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- General Chemistry
- Pollution
- Public Health, Environmental and Occupational Health
- Health, Toxicology and Mutagenesis