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Mineralization of the recalcitrant oxalic and oxamic acids by electrochemical advanced oxidation processes using a boron-doped diamond anode.
Water Res. 2011 Apr; 45(9):2975-84.WR

Abstract

Oxalic and oxamic acids are the ultimate and more persistent by-products of the degradation of N-aromatics by electrochemical advanced oxidation processes (EAOPs). In this paper, the kinetics and oxidative paths of these acids have been studied for several EAOPs using a boron-doped diamond (BDD) anode and a stainless steel or an air-diffusion cathode. Anodic oxidation (AO-BDD) in the presence of Fe(2+) (AO-BDD-Fe(2+)) and under UVA irradiation (AO-BDD-Fe(2+)-UVA), along with electro-Fenton (EF-BDD), was tested. The oxidation of both acids and their iron complexes on BDD was clarified by cyclic voltammetry. AO-BDD allowed the overall mineralization of oxalic acid, but oxamic acid was removed much more slowly. Each acid underwent a similar decay in AO-BDD-Fe(2+) and EF-BDD, as expected if its iron complexes were not attacked by hydroxyl radicals in the bulk. The faster and total mineralization of both acids was achieved in AO-BDD-Fe(2+)-UVA due to the high photoactivity of their Fe(III) complexes that were continuously regenerated by oxidation of their Fe(II) complexes. Oxamic acid always released a larger proportion of NH(4)(+) than NO(3)(-) ion, as well as volatile NO(x) species. Both acids were independently oxidized at the anode in AO-BDD, but in AO-BDD-Fe(2+)-UVA oxamic acid was more slowly degraded as its content decreased, without significant effect on oxalic acid decay. The increase in current density enhanced the oxidation power of the latter method, with loss of efficiency. High Fe(2+) contents inhibited the oxidation of Fe(II) complexes by the competitive oxidation of Fe(2+) to Fe(3+). Low current densities and Fe(2+) contents are preferable to remove more efficiently these acids by the most potent AO-BDD-Fe(2+)-UVA method.

Authors+Show Affiliations

Laboratori d'Electroquímica de Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, Barcelona, Spain.No affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

21477836

Citation

Garcia-Segura, Sergi, and Enric Brillas. "Mineralization of the Recalcitrant Oxalic and Oxamic Acids By Electrochemical Advanced Oxidation Processes Using a Boron-doped Diamond Anode." Water Research, vol. 45, no. 9, 2011, pp. 2975-84.
Garcia-Segura S, Brillas E. Mineralization of the recalcitrant oxalic and oxamic acids by electrochemical advanced oxidation processes using a boron-doped diamond anode. Water Res. 2011;45(9):2975-84.
Garcia-Segura, S., & Brillas, E. (2011). Mineralization of the recalcitrant oxalic and oxamic acids by electrochemical advanced oxidation processes using a boron-doped diamond anode. Water Research, 45(9), 2975-84. https://doi.org/10.1016/j.watres.2011.03.017
Garcia-Segura S, Brillas E. Mineralization of the Recalcitrant Oxalic and Oxamic Acids By Electrochemical Advanced Oxidation Processes Using a Boron-doped Diamond Anode. Water Res. 2011;45(9):2975-84. PubMed PMID: 21477836.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mineralization of the recalcitrant oxalic and oxamic acids by electrochemical advanced oxidation processes using a boron-doped diamond anode. AU - Garcia-Segura,Sergi, AU - Brillas,Enric, Y1 - 2011/03/21/ PY - 2010/12/22/received PY - 2011/02/12/revised PY - 2011/03/10/accepted PY - 2011/4/12/entrez PY - 2011/4/12/pubmed PY - 2011/6/30/medline SP - 2975 EP - 84 JF - Water research JO - Water Res. VL - 45 IS - 9 N2 - Oxalic and oxamic acids are the ultimate and more persistent by-products of the degradation of N-aromatics by electrochemical advanced oxidation processes (EAOPs). In this paper, the kinetics and oxidative paths of these acids have been studied for several EAOPs using a boron-doped diamond (BDD) anode and a stainless steel or an air-diffusion cathode. Anodic oxidation (AO-BDD) in the presence of Fe(2+) (AO-BDD-Fe(2+)) and under UVA irradiation (AO-BDD-Fe(2+)-UVA), along with electro-Fenton (EF-BDD), was tested. The oxidation of both acids and their iron complexes on BDD was clarified by cyclic voltammetry. AO-BDD allowed the overall mineralization of oxalic acid, but oxamic acid was removed much more slowly. Each acid underwent a similar decay in AO-BDD-Fe(2+) and EF-BDD, as expected if its iron complexes were not attacked by hydroxyl radicals in the bulk. The faster and total mineralization of both acids was achieved in AO-BDD-Fe(2+)-UVA due to the high photoactivity of their Fe(III) complexes that were continuously regenerated by oxidation of their Fe(II) complexes. Oxamic acid always released a larger proportion of NH(4)(+) than NO(3)(-) ion, as well as volatile NO(x) species. Both acids were independently oxidized at the anode in AO-BDD, but in AO-BDD-Fe(2+)-UVA oxamic acid was more slowly degraded as its content decreased, without significant effect on oxalic acid decay. The increase in current density enhanced the oxidation power of the latter method, with loss of efficiency. High Fe(2+) contents inhibited the oxidation of Fe(II) complexes by the competitive oxidation of Fe(2+) to Fe(3+). Low current densities and Fe(2+) contents are preferable to remove more efficiently these acids by the most potent AO-BDD-Fe(2+)-UVA method. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/21477836/Mineralization_of_the_recalcitrant_oxalic_and_oxamic_acids_by_electrochemical_advanced_oxidation_processes_using_a_boron_doped_diamond_anode_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(11)00128-X DB - PRIME DP - Unbound Medicine ER -