Dr. Valdes-Morales, Hector

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Dr. Valdes-Morales, Hector
Nombre completo
Valdes Morales, Hector
Facultad
Email
hvaldes@ucsc.cl
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2020 - 20212
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Author: Thibault-Starzyk, Frédéric × Has files: false ×

Research Outputs

Now showing 1 - 2 of 2
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    Publication
    New insight of the influence of acidic surface sites of zeolite on the ability to remove gaseous ozone using operando DRIFTS studies
    (Microporous and Mesoporous Materials, 2020)
    Valdes-Morales, Hector 
    ;
    Ulloa, Francisco J.
    ;
    Solar, Víctor A.
    ;
    Cepeda, Manuel S.
    ;
    Azzolina-Jury, Federico
    ;
    Thibault-Starzyk, Frédéric
    Recently, natural zeolites have started to be used as alternative materials for ozone abatement from working environments. In this study, a surface response methodology based on a D-Optimal design is applied to develop a transition-metal-modified natural zeolite that increases ozone removal efficiency. Ozone adsorption and/or decomposition onto natural and cobalt modified natural zeolite were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Results evidenced that ozone is adsorbed and decomposed at strong Lewis acidic sites, whereas ozone adsorption products interact with surface OH groups. Additionally, DRIFTS studies indicate that nitrous species are adsorbed at acidic sites, reducing the capacity to decompose ozone when ozone is generated from air.
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    Publication
    Removal of chlorinated volatile organic compounds onto natural and Cu-modified zeolite: The role of chemical surface characteristics in the adsorption mechanism
    (Elsevier, 2021)
    Dr. Valdes-Morales, Hector 
    ;
    Riquelme-Díaz, Andrés
    ;
    Solar-Sáez, Víctor
    ;
    Azzolina-Jury, Federico
    ;
    Thibault-Starzyk, Frédéric
    In this study, the effect of chemical surface characteristics of natural and Cu-modified zeolite in the adsorption of chlorinated volatile organic compounds (VOCCls) was investigated using infrared spectroscopy. A natural zeolite mainly composed of clinoptilolite and mordenite was used as a parent material. A succession of chemical and thermal treatments produced a Cu-modified natural zeolite (NZ-Cu) with higher adsorption properties toward the elimination of VOCCls. The adsorption of VOCCls onto NZ-Cu zeolite could be explained by a surface mechanism that comprises the interaction not only with Brønsted acid sites present on the original natural zeolite framework; but also with new Brønsted acid sites formed after the successive treatments.