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Electrochemical mineralization of the azo dye Acid Red 29 (Chromotrope 2R) by photoelectro-Fenton process.
Chemosphere. 2012 Oct; 89(6):751-8.C

Abstract

The degradation of 100 mL of 244 mg L(-1) of the azo dye Acid Red 29 (AR29) has been studied by photoelectro-Fenton (PEF) using an undivided cell containing a boron-doped diamond (BDD) anode and an air-diffusion cathode under UVA irradiation. The effect of current density, concentration of catalytic Fe(2+) and pH on the process was examined. Quick decolorization and almost total mineralization were achieved due to the synergistic action of UVA light and oxidant hydroxyl radicals formed in the bulk from Fenton's reaction between electrogenerated H(2)O(2) at the cathode and added Fe(2+), as well as in the BDD surface from water oxidation. Optimum PEF conditions were found for 0.5-1.0 mM Fe(2+) and pH 3.0. Comparable electro-Fenton (EF) degradations in the dark yielded much poorer mineralization. The decay kinetics of AR29 followed a pseudo-first-order reaction with similar rate for EF and PEF. The azo dye disappeared much more rapidly than solution color, suggesting the formation of colored conjugated products with λ(max) similar to that of AR29. Ion-exclusion HPLC allowed the detection and quantification of tetrahydroxy-p-benzoquinone, oxalic, oxalacetic, tartronic, tartaric, oxamic, malonic and fumaric acids as intermediates in the PEF process. Oxalic acid, accumulated in large extent, was quickly destroyed by the efficient photolysis of Fe(III)-oxalate complexes with UVA light, whereas tartronic and oxamic acids were the most persistent byproducts because of the larger stability of their Fe(III) complexes. The mineralization of the initial N of the azo dye yielded NH(4)(+) ion and NO(3)(-) ion in smaller proportion.

Authors+Show Affiliations

Laboratório de Pesquisas em Eletroquímica, Departamento de Química, Universidade Federal de São Carlos, CP 676, 13560-970 São Carlos-SP, Brazil.No 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

22854020

Citation

Almeida, Lucio Cesar, et al. "Electrochemical Mineralization of the Azo Dye Acid Red 29 (Chromotrope 2R) By photoelectro-Fenton Process." Chemosphere, vol. 89, no. 6, 2012, pp. 751-8.
Almeida LC, Garcia-Segura S, Arias C, et al. Electrochemical mineralization of the azo dye Acid Red 29 (Chromotrope 2R) by photoelectro-Fenton process. Chemosphere. 2012;89(6):751-8.
Almeida, L. C., Garcia-Segura, S., Arias, C., Bocchi, N., & Brillas, E. (2012). Electrochemical mineralization of the azo dye Acid Red 29 (Chromotrope 2R) by photoelectro-Fenton process. Chemosphere, 89(6), 751-8. https://doi.org/10.1016/j.chemosphere.2012.07.007
Almeida LC, et al. Electrochemical Mineralization of the Azo Dye Acid Red 29 (Chromotrope 2R) By photoelectro-Fenton Process. Chemosphere. 2012;89(6):751-8. PubMed PMID: 22854020.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Electrochemical mineralization of the azo dye Acid Red 29 (Chromotrope 2R) by photoelectro-Fenton process. AU - Almeida,Lucio Cesar, AU - Garcia-Segura,Sergi, AU - Arias,Conchita, AU - Bocchi,Nerilso, AU - Brillas,Enric, Y1 - 2012/07/31/ PY - 2012/06/15/received PY - 2012/07/07/revised PY - 2012/07/09/accepted PY - 2012/8/3/entrez PY - 2012/8/3/pubmed PY - 2012/12/12/medline SP - 751 EP - 8 JF - Chemosphere JO - Chemosphere VL - 89 IS - 6 N2 - The degradation of 100 mL of 244 mg L(-1) of the azo dye Acid Red 29 (AR29) has been studied by photoelectro-Fenton (PEF) using an undivided cell containing a boron-doped diamond (BDD) anode and an air-diffusion cathode under UVA irradiation. The effect of current density, concentration of catalytic Fe(2+) and pH on the process was examined. Quick decolorization and almost total mineralization were achieved due to the synergistic action of UVA light and oxidant hydroxyl radicals formed in the bulk from Fenton's reaction between electrogenerated H(2)O(2) at the cathode and added Fe(2+), as well as in the BDD surface from water oxidation. Optimum PEF conditions were found for 0.5-1.0 mM Fe(2+) and pH 3.0. Comparable electro-Fenton (EF) degradations in the dark yielded much poorer mineralization. The decay kinetics of AR29 followed a pseudo-first-order reaction with similar rate for EF and PEF. The azo dye disappeared much more rapidly than solution color, suggesting the formation of colored conjugated products with λ(max) similar to that of AR29. Ion-exclusion HPLC allowed the detection and quantification of tetrahydroxy-p-benzoquinone, oxalic, oxalacetic, tartronic, tartaric, oxamic, malonic and fumaric acids as intermediates in the PEF process. Oxalic acid, accumulated in large extent, was quickly destroyed by the efficient photolysis of Fe(III)-oxalate complexes with UVA light, whereas tartronic and oxamic acids were the most persistent byproducts because of the larger stability of their Fe(III) complexes. The mineralization of the initial N of the azo dye yielded NH(4)(+) ion and NO(3)(-) ion in smaller proportion. SN - 1879-1298 UR - https://www.unboundmedicine.com/medline/citation/22854020/Electrochemical_mineralization_of_the_azo_dye_Acid_Red_29__Chromotrope_2R__by_photoelectro_Fenton_process_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(12)00893-4 DB - PRIME DP - Unbound Medicine ER -