Removal of herbicide 1-chloro-2,4-dinitrobenzene (DNCB) from aqueous solutions by electrochemical oxidation using boron-doped diamond (BDD) and PbO2 electrodes

José Eudes L Santos; Martha A Gómez; D Chianca de Moura; M Cerro-López; Marco A Quiroz; Carlos A Martínez-Huitle

doi:10.1016/j.jhazmat.2020.123850

Removal of herbicide 1-chloro-2,4-dinitrobenzene (DNCB) from aqueous solutions by electrochemical oxidation using boron-doped diamond (BDD) and PbO₂ electrodes

J Hazard Mater. 2021 Jan 15:402:123850. doi: 10.1016/j.jhazmat.2020.123850. Epub 2020 Sep 2.

Authors

José Eudes L Santos¹, Martha A Gómez², D Chianca de Moura³, M Cerro-López², Marco A Quiroz⁴, Carlos A Martínez-Huitle⁵

Affiliations

¹ Universidade Federal do Rio Grande do Norte, CCET - Instituto de Química, Lagoa Nova, CEP 59.072-970, Natal, RN, Brazil. Electronic address: eudesphoenix@gmail.com.
² Universidad de las Américas Puebla, Departamento de Ciencias Químico Biológicas, Sta. Catarina Mártir s/n, Cholula 72820, Puebla, Mexico.
³ Instituto de Educação Superior Presidente Kennedy (IFESP), Grupo Interdisciplinario de Cièncias, Lagoa Nova, CEP 59064-500, Natal, RN, Brazil.
⁴ Universidade Federal do Rio Grande do Norte, CCET - Instituto de Química, Lagoa Nova, CEP 59.072-970, Natal, RN, Brazil.
⁵ Universidade Federal do Rio Grande do Norte, CCET - Instituto de Química, Lagoa Nova, CEP 59.072-970, Natal, RN, Brazil. Electronic address: carlosmh@quimica.ufrn.br.

PMID: 33254819
DOI: 10.1016/j.jhazmat.2020.123850

Abstract

The electrochemical removal of the 1-chloro-2,4-dinitrobenzene (DNCB) herbicide, a potentially carcinogenic agent from aqueous solutions, was performed at PbO₂ and BDD electrodes by bulk electrolysis under galvanostatic control (300 and 400 A m^-2) and under two pH conditions (3 and 9). Results clearly indicated that a 62 % of mineralization was achieved with BDD anode at pH 3, while only a 46 % of electrochemical oxidation (EO) was achieved at PbO₂ electrode. The mineralization current efficiency (MCE) depended on the electrode material, current density, and pH conditions; but, for both PbO₂ and BDD, high MCE was achieved at pH 3 and 300 A m^-2, obtaining 2.54 % and 1.99 % for BDD and PbO₂, respectively. The EO pathway depended on the electrocatalytic properties of each one of the anodes to produce hydroxyl radicals which attacked the DNCB molecule as well as the deactivating effects of the chlorine and nitro groups attached to the aromatic ring on the DNCB structure. Finally, HPLC analyses also showed that phenolic intermediates as well as carboxylic acids were formed, at a different extent, during the electrolysis process on both electrodes.

Keywords: Anodic material activity; Boron-doped diamond; Electrochemical advanced oxidation; Electrolytic oxidation; Organo-chloro-nitro pollutants.

Publication types

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