| Autor: |
Vitaliy I. Timokhin, Miguel L. Rodriguez, Sandra Contreras, Esther Chamarro, Santiago Esplugas |
| Rok vydání: |
2003 |
| Předmět: |
|
| Zdroj: |
Advances in Environmental Research. 7:583-595 |
| ISSN: |
1093-0191 |
| DOI: |
10.1016/s1093-0191(02)00024-2 |
| Popis: |
This paper describes the effect of temperature and initial concentration of H 2 O 2 , Fe(II), PhNO 2 and dissolved oxygen on the degradation rate of PhNO 2 in homogeneous aqueous solution by ‘Fenton-like’ reagent ([H 2 O 2 ] o ≫[Fe(II)] o ). The oxidation products o -, m - and p -nitrophenol were found as intermediates in the ratio 1:1.3–2.8:1.4–2.7 as compared with PhNO 2 when conversion of the latter was less than 25%. This fact suggests that hydroxylation of PhNO 2 was promoted by HO radicals. The reaction was investigated in a completely mixed-batch reactor under a wide range of experimental conditions: pH ∼3.0; 278–318 K; 1.5 2 O 2 ] o o 2 ] o 2 ] o 2 was determined to be 59.7 kJ mol −1 . The degradation rate of PhNO 2 follows pseudo-first-order kinetics. The results of this study demonstrate that the degradation rate of PhNO 2 in the ‘Fenton-like’ system could be predicted with sufficient precision by the equation R D =1.05×10 11 exp(−59.7/ RT )[H 2 O 2 ] o 0.68 [Fe(II)] o 1.67 [PhNO 2 ] o −0.32 . The second-order rate constant for the overall rate of H 2 O 2 decomposition by Fe(III) was found to be 0.83 M −1 s −1 at 298 K. The value of the steady-state HO radical concentration in the ‘Fenton-like’ reaction was found to be ∼10 −13 M, as estimated by two independent methods. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect