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

Authors:  M.H.M.T. Assumpção, A. Moraes, R.F.B. De Souza, R.M. Reis, R.S. Rocha, I. Gaubeur, M.L. Calegaro, P. Hammer, M.R.V. Lanza, M.C. Santos

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 CeO_2−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 −1.1V. However, using the CeO₂/C GDE, in 20 min all of the dipyrone was degraded with 26% mineralization at −1.3V and when the Fenton process was employed, all of the dipyrone was removed after 5 min with 57% mineralization at −1.1V. 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.

Keywords:
Dipyrone degradation
H2O2 electrogeneration
Gas diffusion electrode
Cerium oxide nanoparticles

Published in: Applied catalysis A: General  (Volumes 462–463, Pages 1-310, 10 July 2013)

Publisher: Elsevier      

ISSN Information: 0926-860X

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

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại