Degradation of dipyrone via advanced oxidation processes using a cerium nanostructured electrocatalyst material

Author(s)

Assumpcao, M. H. M. T. ^[1] ; Moraes, A. ^[1] ; De Souza, R. F. B. ^[1] ; Reis, R. M. ^[2] ; Rocha, R. S. ^[2] ; Gaubeur, I. ^[1] ; Calegaro, M. L. ^[2] ; Hammer, P. ^[3] ; Lanza, M. R. V. ^[2] ; Santos, M. C. ^[1]

Affiliation

^[1] Univ Fed Abc, CCNH, LEMN, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Sao Paulo, IQSC, GPEA, BR-13566590 Sao Carlos, SP - Brazil

^[3] UNESP, Inst Quim, BR-14800060 Araraquara, SP - Brazil

• Document type: Journal article
• Source: APPLIED CATALYSIS A-GENERAL; v. 462, p. 256-261, JUL 10 2013.
• Web of Science Citations: 26

Abstract

This work studied the degradation of dipyrone, via electrochemical processes and via electro-Fenton reaction using a 4% CeO2/C gas diffusion electrode (GDE) prepared via modified polymeric precursor method. This material was used to electrochemically generate H2O2 through oxygen reduction. The mean crystallite sizes estimated by the Scherrer equation for 4% CeO2/C were 4 nm for CeO2-x (0 4 4) and 5 nm for CeO2 (1 1 1) while using transmission electron microscopy (TEM) the mean nanoparticle size was 5.4 nm. X-ray photoelectron spectroscopy (XPS) measurements revealed nearly equal concentrations of Ce(III) and Ce(IV) species on carbon, which contained high oxygenated acid species like CO and O-C=O. Electrochemical degradation using Vulcan XC 72R carbon showed that the dipyrone was not removed during the two hour electrolysis in all applied potentials by electro-degradation. Besides, when the Fenton process was employed the degradation was much similar when using cerium catalysts but the mineralization reaches just to 50% at -1.1 V. However, using the CeO2/C GDE, in 20 min all of the dipyrone was degraded with 26% mineralization at -1.3 V and when the Fenton process was employed, all of the dipyrone was removed after 5 min with 57% mineralization at -1.1 V. Relative to Vulcan XC72R, ceria acts as an oxygen buffer leading to an increase in the local oxygen concentration, facilitating H2O2 formation and consequently improving the dipyrone degradation (C) 2013 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 10/16511-6 - Energy generation from biofuel using nanostructures
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Regular Research Grants
• FAPESP's process: 07/04759-0 - Gas diffusion electrodes modified by organometallic compounds for hydrogen peroxide production
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/09145-6 - Study of ethanol electrochemical oxidation mechanism on PtSn, PtCe and PtSnCe using in-situ spectroscopic techniques
• Grantee: Rodrigo Fernando Brambilla de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 10/04539-3 - Synthesis and characterization of nanostructured electrocatalysts for hydrogen peroxide in situ obtention and subsequent degradation of organic pollutants
• Grantee: Mônica Helena Marcon Teixeira Assumpção
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 12/03516-5 - Oxides-C supported electrocatalysts for direct liquid fuel cell anodes
• Grantee: Rodrigo Fernando Brambilla de Souza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral