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Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes.
Chemosphere. 2008 Apr; 71(9):1718-29.C

Abstract

Electrochemical advanced oxidation processes (EAOPs) are environmentally friendly methods based on the destruction of organic pollutants in wastewaters with in situ electrogenerated hydroxyl radical. This species is formed in anodic oxidation (AO) from water oxidation at the anode and in indirect electro-oxidation methods like electro-Fenton (EF) and photoelectro-Fenton (PEF) also from reaction between catalytic Fe2+ and H2O2 continuously produced at the O2-diffusion cathode. The PEF method involves the irradiation of the treated solution with UVA light to enhance the photolysis of organics including Fe(III) complexes. In this work, the oxidation power of such EAOPs to decontaminate synthetic wastewaters of the biocide chloroxylenol (4-chloro-3,5-dimethylphenol) at pH 3.0 is comparatively examined with an undivided electrolytic cell containing a Pt or boron-doped diamond (BDD) anode and a stainless steel or O2-diffusion cathode. The initial chlorine is released as Cl(-) ion, which remains stable in the medium using Pt or is oxidized to Cl2 on BDD. The biocide solutions can be completely decontaminated using AO with a BDD anode, as well as PEF with a Pt or BDD anode. The PEF procedure with a BDD anode is the most powerful method leading to total mineralization in about 300 min, practically independent of current density. When current density rises, the degradation rate of processes increases, but they become less efficient due to the larger enhancement of waste reactions of oxidants. Chloroxylenol is much more rapidly removed in EF and PEF than in AO. 2,6-dimethylhydroquinone, 2,6-dimethyl-p-benzoquinone and 3,5-dimethyl-2-hydroxy-p-benzoquinone are identified as aromatic by-products, and maleic, malonic, pyruvic, acetic and oxalic acids are found as generated carboxylic acids. A general pathway for chloroxylenol mineralization by all EAOPs including the above by-products is proposed.

Authors+Show Affiliations

Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18262595

Citation

Skoumal, Marcel, et al. "Mineralization of the Biocide Chloroxylenol By Electrochemical Advanced Oxidation Processes." Chemosphere, vol. 71, no. 9, 2008, pp. 1718-29.
Skoumal M, Arias C, Cabot PL, et al. Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes. Chemosphere. 2008;71(9):1718-29.
Skoumal, M., Arias, C., Cabot, P. L., Centellas, F., Garrido, J. A., Rodríguez, R. M., & Brillas, E. (2008). Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes. Chemosphere, 71(9), 1718-29. https://doi.org/10.1016/j.chemosphere.2007.12.029
Skoumal M, et al. Mineralization of the Biocide Chloroxylenol By Electrochemical Advanced Oxidation Processes. Chemosphere. 2008;71(9):1718-29. PubMed PMID: 18262595.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes. AU - Skoumal,Marcel, AU - Arias,Conchita, AU - Cabot,Pere Lluís, AU - Centellas,Francesc, AU - Garrido,José Antonio, AU - Rodríguez,Rosa María, AU - Brillas,Enric, Y1 - 2008/02/11/ PY - 2007/10/25/received PY - 2007/12/21/revised PY - 2007/12/28/accepted PY - 2008/2/12/pubmed PY - 2008/8/6/medline PY - 2008/2/12/entrez SP - 1718 EP - 29 JF - Chemosphere JO - Chemosphere VL - 71 IS - 9 N2 - Electrochemical advanced oxidation processes (EAOPs) are environmentally friendly methods based on the destruction of organic pollutants in wastewaters with in situ electrogenerated hydroxyl radical. This species is formed in anodic oxidation (AO) from water oxidation at the anode and in indirect electro-oxidation methods like electro-Fenton (EF) and photoelectro-Fenton (PEF) also from reaction between catalytic Fe2+ and H2O2 continuously produced at the O2-diffusion cathode. The PEF method involves the irradiation of the treated solution with UVA light to enhance the photolysis of organics including Fe(III) complexes. In this work, the oxidation power of such EAOPs to decontaminate synthetic wastewaters of the biocide chloroxylenol (4-chloro-3,5-dimethylphenol) at pH 3.0 is comparatively examined with an undivided electrolytic cell containing a Pt or boron-doped diamond (BDD) anode and a stainless steel or O2-diffusion cathode. The initial chlorine is released as Cl(-) ion, which remains stable in the medium using Pt or is oxidized to Cl2 on BDD. The biocide solutions can be completely decontaminated using AO with a BDD anode, as well as PEF with a Pt or BDD anode. The PEF procedure with a BDD anode is the most powerful method leading to total mineralization in about 300 min, practically independent of current density. When current density rises, the degradation rate of processes increases, but they become less efficient due to the larger enhancement of waste reactions of oxidants. Chloroxylenol is much more rapidly removed in EF and PEF than in AO. 2,6-dimethylhydroquinone, 2,6-dimethyl-p-benzoquinone and 3,5-dimethyl-2-hydroxy-p-benzoquinone are identified as aromatic by-products, and maleic, malonic, pyruvic, acetic and oxalic acids are found as generated carboxylic acids. A general pathway for chloroxylenol mineralization by all EAOPs including the above by-products is proposed. SN - 0045-6535 UR - https://www.unboundmedicine.com/medline/citation/18262595/Mineralization_of_the_biocide_chloroxylenol_by_electrochemical_advanced_oxidation_processes_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(08)00006-4 DB - PRIME DP - Unbound Medicine ER -