Examinando por Materia "Electrocatalytic"

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    Ítem
    The Box-Benkhen experimental design for the optimization of the electrocatalytic treatment of wastewaters with high concentrations of phenol and organic matter.
    (IWA PUBLISHING, 2009-01-01) GilPavas, Edison; Betancourt, Alejandra; Angulo, Monica; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; GilPavas, Edison; Betancourt, Alejandra; Angulo, Monica; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    In this work, the Box-Benkhen experimental Design (BBD) was applied for the optimization of the parameters of the electrocatalytic degradation of wastewaters resulting from a phenolic resins industry placed in the suburbs of Medellin (Colombia). The direct and the oxidant assisted electro-oxidation experiments were carried out in a laboratory scale batch cell reactor, with monopolar configuration, and electrodes made of graphite (anode) and titanium (cathode). A multifactorial experimental design was proposed, including the following experimental variables: initial phenol concentration, conductivity, and pH. The direct electro-oxidation process allowed to reach ca. 88% of phenol degradation, 38% of mineralization (TOC), 52% of Chemical Oxygen Demand (COD) degradation, and an increase in water biodegradability of 13%. The synergetic effect of the electro-oxidation process and the respective oxidant agent (Fenton reactant, potassium permanganate, or sodium persulfate) let to a significant increase in the rate of the degradation process. At the optimized variables values, it was possible to reach ca. 99% of phenol degradation, 80% of TOC and 88% of COD degradation. A kinetic study was accomplished, which included the identification of the intermediate compounds generated during the oxidation process.
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    Ítem
    Substantial improvement of electrocatalytic predictions by systematic assessment of solvent effects on adsorption energies
    (Elsevier B.V., 2020-01-01) Rendón-Calle A.; Builes S.; Calle-Vallejo F.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    Electrocatalytic activities are largely determined by the interplay of adsorbates with substrates and solvents. Although capturing the interactions of those three components is usually arduous, here we provide a simple micro-solvation method to evaluate them in aqueous media. The method helps determine: (a) the number of water molecules making hydrogen bonds with the adsorbates, and (b) the energetic stabilization of the adsorbates by those hydrogen bonds. To evaluate the usefulness of the method, we consider CO2 reduction to CO, CH4, and CH3OH on Cu, Ag, Au, and Zn. Applying the calculated solvation corrections, we find good agreement with experiments in the predicted pathways and onset potentials, with an average error of only 0.07 V. Conversely, models with ad hoc or implicit solvation corrections predict unlikely pathways and onset potentials with considerably larger errors. These results indicate that accurate methods to assess solvent-adsorbate interactions contribute to improve computational electrocatalysis models. © 2020 Elsevier B.V.