Advanced oxidation processes for the degradation of p-hydroxybenzoic acid 2: Photo-assisted Fenton oxidation

✍ Scribed by J Beltran; J Torregrosa; J R Dominguez; J A Peres

• Publisher: Wiley (John Wiley & Sons)
• Year: 2001
• Tongue: English
• Weight: 159 KB
• Volume: 76
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/jctb.512

✦ Synopsis

Abstract

Oxidation of p‐hydroxybenzoic acid in aqueous solution by the photo‐assisted Fenton reaction (Fe^2+^ + H~2~O~2~ + UV) has been studied. The effects of ferrous ion concentration (0.05, 0.14 and 0.29 mmol dm^−3^), temperature (10, 20, 30 and 40 °C), and initial hydrogen peroxide concentration (0.7, 1.4, 2.2 and 2.9 mmol dm^−3^) on the p‐hydroxybenzoic acid conversion were established. Experimental results indicate that the kinetics of this oxidation process fits pseudo‐first‐order kinetics well. The overall kinetic rate constant was split into two components: direct oxidation by UV radiation (photolysis) and oxidation by free radicals (mainly OH·) generated in the system. The importance of these two reaction paths for each specific value of ferrous ion concentration, temperature and initial hydrogen peroxide concentration was evaluated. A semi‐empirical expression is proposed for the overall reaction rate which takes into account both oxidation pathways and is a function of operating variables.

© 2001 Society of Chemical Industry