Degradation of 4-aminoantipyrine by electro-oxidation with a boron-doped diamond anode: Optimization by central composite design, oxidation products and toxicity

Lucas de Melo da Silva; Fábio Gozzi; Ignasi Sirés; Enric Brillas; Silvio Cesar de Oliveira; Amilcar Machulek Junior

doi:10.1016/j.scitotenv.2018.03.092

Degradation of 4-aminoantipyrine by electro-oxidation with a boron-doped diamond anode: Optimization by central composite design, oxidation products and toxicity

Sci Total Environ. 2018 Aug 1:631-632:1079-1088. doi: 10.1016/j.scitotenv.2018.03.092. Epub 2018 Mar 16.

Authors

Lucas de Melo da Silva¹, Fábio Gozzi¹, Ignasi Sirés², Enric Brillas³, Silvio Cesar de Oliveira¹, Amilcar Machulek Junior⁴

Affiliations

¹ Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller, 1555; CP 549, Campo Grande, MS 79074-460, Brazil.
² Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain. Electronic address: i.sires@ub.edu.
³ Laboratori d'Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Facultat de Química, Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
⁴ Institute of Chemistry, Federal University of Mato Grosso do Sul, Av. Senador Filinto Muller, 1555; CP 549, Campo Grande, MS 79074-460, Brazil. Electronic address: machulekjr@gmail.com.

PMID: 29727934
DOI: 10.1016/j.scitotenv.2018.03.092

Abstract

Electro-oxidation with electrogenerated H₂O₂ (EO-H₂O₂) was applied to treat acidic aqueous solutions of 4-aminoantipyrine (4-AA), a persistent drug metabolite of dipyrone, in sulfate medium. Trials were made using a boron-doped diamond anode in the presence of H₂O₂ electrogenerated on site. A 2⁴ central composite design (CCD) was employed to evaluate the effect of four independent variables, namely current density (j), pH, 4-AA concentration and electrolysis time, on the percentages of degradation and mineralization, as well as on mineralization current efficiency (MCE). Predicted responses agreed with observed values, showing linear trendlines with good R² and R²_adj values. The degradation was optimum at j=77.5mAcm^-2, pH3.5 and 62.5mgL^-1 4-AA, leading to 63% and 99% removal after 3 and 7min, respectively. For those solutions, the largest mineralization was found at j=77.5mAcm^-2, attaining 45% abatement at 175min. Low MCE values were obtained in all electrolyses. An initial route for 4-AA degradation is proposed based on one dimer and eleven aromatic and aliphatic intermediates detected in the treated solutions at pH3.5 by LC-MS. The initial 62.5mgL^-1 solution at pH3.5 presented acute toxicity on Artemia salina larvae, with LC₅₀=13.6mgL^-1, being substantially reduced after 3 and 7min of EO-H₂O₂ at j=77.5mAcm^-2 due to the formation of less toxic derivatives.

Keywords: 4-Aminoantipyrine; Acute toxicity; BDD; Central composite design; Electrochemical oxidation; Wastewater treatment.