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Photoelectrocatalytic/photoelectro-Fenton coupling system using a nanostructured photoanode for the oxidation of a textile dye: Kinetics study and oxidation pathway.
Chemosphere. 2015 Oct; 136:63-71.C

Abstract

In this study, a coupled photoelectrocatalytic/photoelectro-Fenton reactor was designed to enhance the degradation efficiency of organic pollutants and tested using the azo dye Orange G as a model compound. Pt-decorated TiO2 nanotubes were used as a photoanode with an air-diffusion polytetrafluoroethylene cathode for H2O2 generation. The sum of individual effects of coupling the photoelectrocatalytic and photoelectro-Fenton processes was evaluated as a function of the decolorization and mineralization of Orange G solutions. The dye solutions were only completely decolorized in more acidic conditions (pH 3.0). The mineralization of the Orange G solutions increased in the sequence photoelectrocatalytic<electro-Fenton<coupled photoelectrocatalytic/photoelectro-Fenton due to the gradual increase in the production of OH radicals. Total organic carbon reductions of 80% for photoelectrocatalysis, 87% for electro-Fenton and 97% for the coupled processes were obtained when using an applied electric charge per unit volume of electrolyzed solution of 200 mA h L(-1). The Orange G decays for all treatments followed pseudo-first-order kinetics, suggesting the attack of a constant concentration of OH radicals. Aromatics such as naphthalenic and benzenic compounds were formed as by-products and were identified using LC-MS/MS analysis. In addition, the generated aliphatic acids were identified using ion-exclusion high-performance liquid chromatography. The final by-products of oxalic and formic acid were identified as ultimate by-products and formed Fe(III) complexes that were rapidly mineralized to CO2 by UV-Vis irradiation. Then, according to the identified oxidation by-products, a plausible pathway was proposed for the degradation of Orange G dye by the coupled process.

Authors+Show Affiliations

Institute of Chemistry of Araraquara, Department of Analytical Chemistry, UNESP, Rua Francisco Degni, 55, 14800-900 Araraquara, SP, Brazil. Electronic address: luciobonn@gmail.com.Institute of Chemistry of Araraquara, Department of Analytical Chemistry, UNESP, Rua Francisco Degni, 55, 14800-900 Araraquara, SP, Brazil.Institute of Chemistry of Araraquara, Department of Analytical Chemistry, UNESP, Rua Francisco Degni, 55, 14800-900 Araraquara, SP, Brazil.

Pub Type(s)

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

Language

eng

PubMed ID

25935699

Citation

Almeida, Lucio C., et al. "Photoelectrocatalytic/photoelectro-Fenton Coupling System Using a Nanostructured Photoanode for the Oxidation of a Textile Dye: Kinetics Study and Oxidation Pathway." Chemosphere, vol. 136, 2015, pp. 63-71.
Almeida LC, Silva BF, Zanoni MV. Photoelectrocatalytic/photoelectro-Fenton coupling system using a nanostructured photoanode for the oxidation of a textile dye: Kinetics study and oxidation pathway. Chemosphere. 2015;136:63-71.
Almeida, L. C., Silva, B. F., & Zanoni, M. V. (2015). Photoelectrocatalytic/photoelectro-Fenton coupling system using a nanostructured photoanode for the oxidation of a textile dye: Kinetics study and oxidation pathway. Chemosphere, 136, 63-71. https://doi.org/10.1016/j.chemosphere.2015.04.042
Almeida LC, Silva BF, Zanoni MV. Photoelectrocatalytic/photoelectro-Fenton Coupling System Using a Nanostructured Photoanode for the Oxidation of a Textile Dye: Kinetics Study and Oxidation Pathway. Chemosphere. 2015;136:63-71. PubMed PMID: 25935699.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photoelectrocatalytic/photoelectro-Fenton coupling system using a nanostructured photoanode for the oxidation of a textile dye: Kinetics study and oxidation pathway. AU - Almeida,Lucio C, AU - Silva,Bianca F, AU - Zanoni,Maria V B, Y1 - 2015/05/15/ PY - 2015/03/06/received PY - 2015/04/15/revised PY - 2015/04/16/accepted PY - 2015/5/4/entrez PY - 2015/5/4/pubmed PY - 2016/2/19/medline KW - Dye degradation pathway KW - Photoelectro-Fenton KW - Photoelectrocatalysis KW - Pt-decorated TiO(2)NT anode KW - Wastewater treatment SP - 63 EP - 71 JF - Chemosphere JO - Chemosphere VL - 136 N2 - In this study, a coupled photoelectrocatalytic/photoelectro-Fenton reactor was designed to enhance the degradation efficiency of organic pollutants and tested using the azo dye Orange G as a model compound. Pt-decorated TiO2 nanotubes were used as a photoanode with an air-diffusion polytetrafluoroethylene cathode for H2O2 generation. The sum of individual effects of coupling the photoelectrocatalytic and photoelectro-Fenton processes was evaluated as a function of the decolorization and mineralization of Orange G solutions. The dye solutions were only completely decolorized in more acidic conditions (pH 3.0). The mineralization of the Orange G solutions increased in the sequence photoelectrocatalytic<electro-Fenton<coupled photoelectrocatalytic/photoelectro-Fenton due to the gradual increase in the production of OH radicals. Total organic carbon reductions of 80% for photoelectrocatalysis, 87% for electro-Fenton and 97% for the coupled processes were obtained when using an applied electric charge per unit volume of electrolyzed solution of 200 mA h L(-1). The Orange G decays for all treatments followed pseudo-first-order kinetics, suggesting the attack of a constant concentration of OH radicals. Aromatics such as naphthalenic and benzenic compounds were formed as by-products and were identified using LC-MS/MS analysis. In addition, the generated aliphatic acids were identified using ion-exclusion high-performance liquid chromatography. The final by-products of oxalic and formic acid were identified as ultimate by-products and formed Fe(III) complexes that were rapidly mineralized to CO2 by UV-Vis irradiation. Then, according to the identified oxidation by-products, a plausible pathway was proposed for the degradation of Orange G dye by the coupled process. SN - 1879-1298 UR - https://www.unboundmedicine.com/medline/citation/25935699/Photoelectrocatalytic/photoelectro_Fenton_coupling_system_using_a_nanostructured_photoanode_for_the_oxidation_of_a_textile_dye:_Kinetics_study_and_oxidation_pathway_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(15)00381-1 DB - PRIME DP - Unbound Medicine ER -