Browsing by Author "Escalona, N."
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- ItemCatalytic hydrodeoxygenation of anisole over Re-MoOx/TiO2 and Re-VOx/TiO2 catalysts(2017) Ghampson, I. T.; Pecchi, G.; Fierro, J. L. G.; Videla Leiva, Álvaro Rodrigo; Escalona, N.
- ItemCatalytic performance of 2D-Mxene nano-sheets for the hydrodeoxygenation (HDO) of lignin-derived model compounds(2020) Blanco, E; Rosenkranz, Andreas; Espinoza-González, R; Fuenzalida, VM; Zhang, ZY; Suarez, S.; Escalona, N.
- ItemCO2 methanation over nickel-zro2 catalyst supported on carbon nanotubes: A comparison between two impregnation strategies(2018) Romero-Saez, M.; Dongil, A. B.; Benito, N.; Espinoza-Gonzalez, R.; Escalona, N.; Gracia, F.
- ItemConversion of levulinic acid over Ag substituted LaCoO3 perovskite(2021) Seguel, J.; Leal, E.; Zarate, X.; Saavedra-Torres, M.; Schott Verdugo, Eduardo Enrique; Díaz de León, J.N.; Blanco, E.; Escalona, N.; Pecchi, G.; Sepúlveda, C.
- ItemConversion of levulinic acid over rhenium oxide catalysts: Effect of metal content(2021) Bassi, R.; Baeza, P.; Sepulveda, C.; Ghampson, I. T.; Camu, E.; Bruckner, A.; Bentrup, U.; Fierro, J. L. G.; Escalona, N.The conversion of levulinic acid over rhenium oxide catalysts supported on ZrO2 and SiO2 in a batch reactor at 200 degrees C and 5 MPa of H-2 pressure was studied. The catalysts were prepared by incipient wetness impregnation with nominal loadings of 5-18 wt.%. The catalysts were characterized by N-2 physisorption, field emission scanning electron microscopy, X-ray diffraction, H-2-temperature programmed reduction, Fourier transform infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy. The catalysts were highly active and selective to gamma-valerolactone. Catalytic activity, expressed as initial reaction rate and based on catalyst weight, was correlated with dispersion. The difference in the activity trend was attributed to ReOx-support interaction: ZrO2 interacted more strongly with ReOx and modified the electronic character of the sites, whereas SiO2 interacted weakly with ReOx, leading to unmodified Re active sites, irrespective of Re loading. All the catalysts exceeded 90 % selectivity to GVL.
- ItemCorrigendum: Selective photocatalytic conversion of guaiacol using g-C3N4 metal free nanosheets photocatalyst to add-value products (vol 421, 113513, 2021)(ELSEVIER SCIENCE SA, 2022) Rojas, S. D.; Espinoza Villalobos, N.; Salazar, R.; Escalona, N.; Contreras, D.; Melin, V.; Laguna Bercero, M. A.; Sanchez Arenillas, M.; Vergara, E.; Caceres Jensen, L.; Rodriguez Becerra, J.; Barrientos, L.© 2021 Elsevier B.V.The authors regret that in the above article, affiliation c is mistaken. Therefore, afiliation c should be: c Departamento de Química de los materiales, Laboratorio de electroquímica Medio ambiental, LEQMA, Universidad de Santiago de Chile, Avenida Libertador Bernardo O'Higgins 3363, Estación Central, Santiago 9170376, Chile The authors would like to apologize for any inconvenience caused.
- ItemEffect of supplementary cementitious materials on viscosity of cement-based pastes(2022) Navarrete, I.; Kurama, Y.; Escalona, N.; Brevis Vergara, Wernher Ariel; Lopez, M.; CEDEUS (Chile)
- ItemEnhancing the Biosorption Capacity of Macrocystis pyrifera: Effects of Acid and Alkali Pretreatments on Recalcitrant Organic Pollutants Removal(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Varas, M.; Castro-Rojas, J.; Contreras-Porcia, L.; Ureta-Zanartu, M.S.; Blanco, E.; Escalona, N.; Muñoz, E.; Garrido Ramirezm, E.© 2025 by the authors.The effects of acid and alkali pretreatments on the physicochemical and textural properties of Macrocystis pyrifera were evaluated to assess its potential for removing recalcitrant organic pollutants from aquatic systems. Untreated (UB), acid-pretreated (ACPB), and alkali-pretreated (ALPB) seaweed biomass were characterized using SEM, FTIR-ATR, N2 adsorption–desorption, and potentiometric titrations. Adsorption isotherms and kinetic studies, using methylene blue (MB) as a model pollutant, were conducted to evaluate removal performance. All biosorbents exhibited Langmuir behavior, with maximum adsorption capacities of 333 mg g−1 (UB), 189 mg g−1 (ACPB), and 526 mg g−1 (ALPB). FTIR-ATR and SEM analyses revealed that alkali pretreatment increased the abundance of hydroxyl, carboxylate, and sulfonated functional groups on the seaweed cell walls, along with greater porosity and surface roughness, resulting in enhanced MB adsorption. In contrast, acid pretreatment increased the exposure of carboxylic, amine, and amide functional groups, reducing the electrostatic interactions. The adsorption energy values further supported this, while the intra-particle diffusion model indicated a two-step process involving MB diffusion onto the seaweed surface, followed by diffusion into internal pores. These findings highlight the potential application of Macrocystis pyrifera-based biosorbents in the treatment of wastewater containing recalcitrant organic pollutants.
- ItemEnhancing the Biosorption Capacity of Macrocystis pyrifera: Effects of Acid and Alkali Pretreatments on Recalcitrant Organic Pollutants Removal(Elsevier, 2025) Varas, M.; Castro-Rojas, J.; Contreras-Porcia, L.; Ureta-Zanartu, M.S.; Blanco, E.; Escalona, N.; Muñoz, E.; Garrido Ramirezm, E.© 2025 by the authors.The effects of acid and alkali pretreatments on the physicochemical and textural properties of Macrocystis pyrifera were evaluated to assess its potential for removing recalcitrant organic pollutants from aquatic systems. Untreated (UB), acid-pretreated (ACPB), and alkali-pretreated (ALPB) seaweed biomass were characterized using SEM, FTIR-ATR, N2 adsorption–desorption, and potentiometric titrations. Adsorption isotherms and kinetic studies, using methylene blue (MB) as a model pollutant, were conducted to evaluate removal performance. All biosorbents exhibited Langmuir behavior, with maximum adsorption capacities of 333 mg g−1 (UB), 189 mg g−1 (ACPB), and 526 mg g−1 (ALPB). FTIR-ATR and SEM analyses revealed that alkali pretreatment increased the abundance of hydroxyl, carboxylate, and sulfonated functional groups on the seaweed cell walls, along with greater porosity and surface roughness, resulting in enhanced MB adsorption. In contrast, acid pretreatment increased the exposure of carboxylic, amine, and amide functional groups, reducing the electrostatic interactions. The adsorption energy values further supported this, while the intra-particle diffusion model indicated a two-step process involving MB diffusion onto the seaweed surface, followed by diffusion into internal pores. These findings highlight the potential application of Macrocystis pyrifera-based biosorbents in the treatment of wastewater containing recalcitrant organic pollutants.
- ItemSUPPORT EFFECT ON CONVERSION OF QUINOLINE OVER ReS2 CATALYST(2016) Bassi, R.; Villarroel, M.; Gil-Llambias, F. J.; Baeza, P.; Garcia-Fierro, J. L.; Martinez, N.; Olivera, P.; Leiva, K.; Escalona, N.The conversion of quinoline over ReS2 supported on gamma-Al2O3, SiO2, ZrO2 and TiO2 catalysts in a batch reactor at 300 degrees C and 5 MPa of hydrogen pressure was studied. The catalysts were prepared by wet impregnation with a loading of 1.5 atoms of Re per nm(2) of support. The catalysts were characterized by N-2 adsorption, X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD). The Re(x)/supports catalysts displayed high activities for the conversion of quinoline, although negligible formation of N-free compounds (hydrodenitrogenation) were observed. The intrinsic activities of ReS2 were modified by the support decreased in the order: Re/TiO2 > Re/ZrO2 > Re/SiO2 > Re/g-Al2O3. The highest activity displayed by the Re/TiO2 catalyst was correlated with the Re dispersion and formation of ReS2 species. Meanwhile, the lower conversion of quinoline over the Re/ZrO2, Re/SiO2 and Re/g-Al2O3 catalysts was related to the combined effect of the textural properties of catalysts and the formation of ReS(2-x) species on the supports.