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Influence of pressure and cell design on the production of ozone and organic degradation

2022; Elsevier BV; Volume: 297; Linguagem: Inglês

10.1016/j.seppur.2022.121529

1873-3794

M. Rodríguez-Peña, J.A. Barrios, Justo Lobato, Cristina Sáez, Carlos Barrera-Díaz, Manuel A. Rodrigo,

Industrial Gas Emission Control

This work evaluates the effect of pressure on the electrochemical production of ozone and on the degradation of organics contained in wastewater. Results are compared between two commercial highly-efficient electrolyzers, namely CabECO®️ and CONDIAPURE®️. Results show that, in acidic electrolytes, the main mechanism for ozone electrogeneration is oxygen oxidation rather than water oxidation. Furthermore, although both cells are based on the same technology, CabECO®️ cell shows the best performances , pointing out the huge effect of the mechanical design. Electrolyte composition proved to be a key parameter, and comparing results on perchloric and sulfuric acid solutions, an increase in organic degradation efficiency was observed when working with H2SO4 solutions. However, an increase in ozone production in electrolytes based on HClO4 solutions was observed. Results also exhibit that pressure directly influences the degradation of clopyralid showing that an increase in pressure decreases the degradation rate of the pesticide while, at the same time, increases ozone production. These can be interpreted in terms of the activation of the ozone (at lower pressures and in electrolytes containing sulfate ions) to other more powerful species (sulfate and hydroxyl radicals) that favor the oxidation of organics and, also, by the higher stability and solubility of ozone at higher pressures, which may result in degradation pathways directly controlled by molecular ozone, rather than by radical species.