Photoelectrolysis of clopyralid wastes with a novel laser-prepared MMO-RuO2TiO2 anode

Géssica O S Santos; Katlin I B Eguiluz; Giancarlo R Salazar-Banda; Cristina Saez; Manuel A Rodrigo

doi:10.1016/j.chemosphere.2019.125455

Photoelectrolysis of clopyralid wastes with a novel laser-prepared MMO-RuO₂TiO₂ anode

Chemosphere. 2020 Apr:244:125455. doi: 10.1016/j.chemosphere.2019.125455. Epub 2019 Nov 25.

Authors

Géssica O S Santos¹, Katlin I B Eguiluz², Giancarlo R Salazar-Banda², Cristina Saez³, Manuel A Rodrigo⁴

Affiliations

¹ Electrochemistry and Nanotechnology Laboratory (LEN), Research and Technology Institute (ITP), Aracaju, SE, Brazil; Processes Engineering Post-graduation - PEP, Universidade Tiradentes, 49037-580, Aracaju, SE, Brazil; Department of Chemical Engineering, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071, Ciudad Real, Spain.
² Electrochemistry and Nanotechnology Laboratory (LEN), Research and Technology Institute (ITP), Aracaju, SE, Brazil; Processes Engineering Post-graduation - PEP, Universidade Tiradentes, 49037-580, Aracaju, SE, Brazil.
³ Department of Chemical Engineering, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071, Ciudad Real, Spain.
⁴ Department of Chemical Engineering, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071, Ciudad Real, Spain. Electronic address: manuel.rodrigo@uclm.es.

PMID: 31790985
DOI: 10.1016/j.chemosphere.2019.125455

Abstract

This paper studies the applicability of a novel laser-prepared mixed metal oxide (MMO-RuO₂TiO₂) anode in the photoelectrochemical degradation of clopyralid, a toxic and biorefractory herbicide. Results are compared to those obtained using the well-known boron-doped diamond (BDD) anode and demonstrate that, although the electrolysis with diamond is more effective than that obtained with the new electrode, the irradiation of UVC light makes the novel MMO material more effective in chloride media. It was explained in terms of the homolysis of hypochlorous acid/hypochlorite to form chloride and hydroxyl radicals. Photoelectrochemical degradation with MMO produced a marked synergistic effect in TOC removal, especially in the presence of chloride ions. On the contrary, for the BDD anode, at the tested conditions, antagonisms were found in both sulfate and chloride media. These important synergisms allows finding conditions in which the novel anode can be competitive with the BDD.

Keywords: BDD; Electrolysis; Laser; MMO; Photoelectrolysis.

MeSH terms

Boron
Chlorides
Diamond
Electrodes
Electrolysis / methods
Herbicides / chemistry*
Hydroxyl Radical
Lasers
Light
Models, Chemical*
Oxidation-Reduction
Oxides
Picolinic Acids / chemistry*
Sulfates

Substances

Chlorides
Herbicides
Oxides
Picolinic Acids
Sulfates
clopyralid
Hydroxyl Radical
Diamond
Boron