Fenton and photo-Fenton degradation of 2-chlorophenol:: Multivariate analysis and toxicity monitoring

The simultaneous occurrence of Fenton and photo-Fenton reactions is an attractive process for contamination remediation involving high toxicity and low biodegradability species. In this work, a multivariate experimental design was applied to the treatment of 2-chlorophenol, as representative of chlorinated aromatic compounds, in order to evaluate the use of the Fenton reagent under light irradiation (wavelength close to 400 nm for photo-Fenton reactions and up to 550 nm for Fenton-like reactions). Hence, the aim of this work is to study the evolution of toxicity through all the degradation process by characterizing the toxicity level of 2-chlorophenol and its reaction intermediates as a function of temperature and the Fenton reagent loads. Factorial experimental design was used to assign each variable's weight in TOC removal after 30 min of reaction. Hydrogen peroxide concentration appears as a main direct effect for a favorable TOC reduction. Temperature has also an important effect in the 2-chlorophenol degradation, especially when the ratio of Fenton reagents is not correctly chosen. More than 90% TOC reduction could be achieved in only 30 min of treatment. In addition, the HPLC analysis showed the elimination of the studied compound and its byproducts under specific working conditions. Finally, results indicated the importance of taking into account toxicity evolution. (C) 2007 Elsevier B.V. All rights reserved.