Browsing by Author "Baeza, P."

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Conversion 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.
  • Thumbnail Image
    Item
    Effect of the hydrogen spillover on the selectivity of dibenzothiophene hydrodesulfurization over CoSx/γ-Al2O3, NiSx/γ-Al2O3 and MoS2/γ-Al2O3 catalysts
    (2006) Escalona, Néstor; Garcia, R.; Lagos, Gustavo; Navarrete, C.; Baeza, P.; Gil Llambías, Francisco Javier
  • No Thumbnail Available
    Item
    Removal of Pharmaceuticals from an Aqueous Matrix by Adsorption on Metal-Organic Framework MIL-100(Cr)
    (2023) Matus, C.; Baeza, P.; Serrano-Lotina, A.; Pasten, B.; Ramirez, M. Fernanda; Ojeda, J.; Camu, E.
    In this work, the new class of porous materials MIL-100(Cr) was synthetized using a solvent-free methodology to evaluate the removal of the pharmaceutical contaminants Paracetamol, Ibuprofen, Metformin, or Carbamazepine from aqueous sources. This adsorbent was characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy with attenuated total reflectance, Raman spectroscopy, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy. The characterization technique results indicated that the synthesized MIL-100(Cr) has a non-uniform structure of different sizes as well as a low crystallinity structure and is thermally stable up to similar to 300 degrees C with a surface negatively charged in the assay pH range and the presence of two types of cavities, pentagonal and hexagonal, with sizes of 1.10 nm and 1.49 nm. The results of adsorption demonstrated higher values of Carbamazepine, Paracetamol, and Ibuprofen on MIL-100(Cr) with values of 21 mg L-1, 20 mg L-1, and 17 mg L-1, respectively, while in the case of Metformin, a lower value of 12 mg L-1 was observed. The differences in the adsorption values were explained by different interactions between the pharmaceutical compounds and the MIL-100(Cr), such as pi-pi and electrostatic interactions and hydrogen bonds. Despite the low crystallinity observed in MIL-100(Cr), due to synthesis solvent-free methodologies used, this material maintains the structural and physicochemical characteristics required to be utilized as an adsorbent of pharmaceutical contaminants from aqueous solutions.
  • No Thumbnail Available
    Item
    SUPPORT 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.
  • Thumbnail Image
    Item
    Synergism of Extruded and Monolithic Co-Mo/γ-AL2O3-Sepiolite Catalytic Systems in the Hydrodesulphurization Reaction
    (2016) Baeza, P.; Villarroel, M.; Villanueva, R.; Gil Llambías, Francisco Javier; Ávila, P.