Browsing by Author "Barrientos Poblete, Lorena Julieta"

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    Effects of two chemical treatments on the optical properties of the rutile crystalline phase.Efectos de dos tratamientos químicos sobre las propiedades ópticas de la fase cristalina de rutilo
    (2022) Retamoso Llamas Claudia Patricia; Escalona Burgos, Néstor Guillermo; González Hormazábal, Marcelo Andrés; Barrientos Poblete, Lorena Julieta
    © 2022, Universidad de Los Andes. All rights reserved.The optical properties of the photocata-lysts are related to the band gap since it impacts the results of contaminant removal effectiveness during irradiation. Among the photocatalysts, anatase has been studied more than rutile. In the present work, chemical treatments were carried out on rutile to shift the band gap towards the visible zone of the electromagnetic spectrum. The results suggest that the incipient impregnation with Fe salts effectively shifts the energy gap to the visible area, significantly decreasing the maximum absorbance levels. While the partial reduction of rutile increases the absorbance levels when carried out at a temperature of 250 °C.
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    Exploration of the initial photocatalytic activity parameters of ?Fe2O3–rutile for methylene blue discoloration in water through the OFAT process
    (2023) Retamoso Llamas, Claudia Patricia; Escalona Burgos, Néstor Guillermo; González Hormazábal, Marcelo Andrés; Barrientos Poblete, Lorena Julieta
    The photocatalyst response is related to experimental conditions that improve effectiveness in removing contaminants. A parameter analysis of ?Fe2O3–rutile and water contaminated with methylene blue (MB) was carried out to obtain initial factors that impact reaction conditions. Moreover, the following factors were tested: the ?Fe2O3–rutile load, the initial MB concentration, and the initial pH solution. These one-factor-at-a-time variations were made to explore the conditions of each variable with the other two fixed. Above all, a significant change was identified in the initial discoloration rate from 5.2 to 35.56 10?9 mol g?1 s?1, with 34 and 91 % removal effectiveness, respectively. These results were achieved with an ?Fe2O3–rutile load of 1.0 g L?1, an initial MB concentration of 8.0 10?6 mol L?1, and a pH of 8.8, after 540 min of irradiation. This high discoloration effectiveness with ?Fe2O3–rutile had not been previously reported. The parameter that most influenced the photocatalytic activity was the initial pH solution due to the interaction of the point of zero charge of ?Fe2O3–rutile and the contaminated water; the pH of the solution exceeds the isoelectric point, it causes electrostatic forces and hydrogen bonds with MB to increase its effectiveness. The combination of ?Fe2O3–rutile and the removal of methylene blue in water improves adsorption on the surface of the ?Fe2O3–rutile, providing the highest discoloration rate.