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Type: Artigo de periódico
Title: Reductive/oxidative treatment with superior performance relative to oxidative treatment during the degradation of 4-chlorophenol
Author: Raja, P
Bozzi, A
Jardim, WF
Mascolo, G
Renganathan, R
Kiwi, J
Abstract: This study obtained information on the effectiveness of the photo-assisted Fenton oxidation of 4-chlorophenol (4-CP) combined with zero-valent pretreatment. The kinetic rate parameters of the process as well as the operating conditions were determined. Homogeneous photo-assisted Fenton enhanced processes lead to similar to 33% mineralization of 4-chlorophenol (1.25 mM) in solutions containing Fe-ions (210 mg/l) and H2O2 (10 mM) within 2 It under visible light irradiation. When this solution was pretreated with zero-valent Fe (14 g/70 ml) in Ar atmosphere, the mineralization attained levels of > 80% after the second stage photo-assisted Fenton process. Intermediates that could be effectively degraded by photo-Fenton reactions were not attained in the absence of zero-valent Fe pretreatment. The pretreatment by zero-valent Fe under light lead to about 70% of the stoichiometric amount of chloride contained in 4-CP. Partial recovery of chloride ions indicated the formation of chloro-intermediates. These intermediates were experimentally detected by high-pressure liquid chromatograph (HPLC)-MS and the most important intermediates were identified. Fenton photo-assisted processes were effective employing very low concentrations of Fe2+ (2-5 mg/l) after the pretreatment stage that do not need to be separated after the 4-CP degradation process. This is important for the practical application of the novel combined heterogeneous-homogeneous process. Evidence for the stable catalytic performance of the coupled process to degrade 4-CP is presented. The effect on the 4-CP degradation of Fe-ion, H2O2, 4-CP concentration and gas atmosphere was systematically investigated. The activation energy (Ea) of 2.66 U/mol was found for the abatement of 4-CP. (c) 2005 Elsevier B.V. All rights reserved.
Subject: heterogeneous/homogeneous photo-Fenton processes
zero-valent Fe
4-chlorophenol decomposition
TOC reduction
activation energy
GC-MS of intermediates
reductive processes
Country: Holanda
Editor: Elsevier Science Bv
Citation: Applied Catalysis B-environmental. Elsevier Science Bv, v. 59, n. 41732, n. 249, n. 257, 2005.
Rights: fechado
Identifier DOI: 10.1016/j.apcatb.2005.02.014
Date Issue: 2005
Appears in Collections:Unicamp - Artigos e Outros Documentos

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