Sono- and photoelectrocatalytic processes for the removal of ionic liquids based on the 1-butyl-3-methylimidazolium cation

In this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc) and chloride (BmimCl) were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by...

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Detalles Bibliográficos
Autores: Fernández Mena, Ismael, Cotillas, Salvador, Díaz, Elena, Sáez Jiménez, Cristina, Mohedano, Ángel Fernández, Rodrigo Rodrigo, Manuel Andrés
Tipo de recurso: artículo
Fecha de publicación:2019
País:España
Institución:Universidad de Castilla-La Mancha
Repositorio:RUIdeRA. Repositorio Institucional de la UCLM
OAI Identifier:oai:ruidera.uclm.es:10578/29298
Acceso en línea:https://doi.org/10.1016/j.jhazmat.2017.12.015
http://hdl.handle.net/10578/29298
Access Level:acceso abierto
Palabra clave:Electrolysis
Photoelectrolysis
Sonoelectrolysis
Ionic liquid
1-Butyl-3-methylimidazolium
Descripción
Sumario:In this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc) and chloride (BmimCl) were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by UV light or with the application of high-frequency ultrasound (US). Despite its complex heterocyclic structure, the Bmim+ cation was successfully depleted with the three technologies that were tested and was mainly transformed into four different organic intermediates, an inorganic nitrogen species and carbon dioxide. Regardless of the technology that was evaluated, removal of the heterocyclic ring is much less efficient (and much slower) than oxidation of the counter ion. In turn, the counter ion influences the rate of removal of the ionic liquid cation. Thus, the electrolysis and photoelectrolysis of BmimAc are much less efficient than sonoelectrolysis, but their differences become much less important in the case of BmimCl. In this later case, the most efficient technology is photoelectrolysis. This result is directly related to the generation of free radicals in the solution by irradiation of the electrochemical system with UV light, which contributes significantly to the removal of Bmim+.