Browsing by Author "Canales, Roberto"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    An experimental methodology to validate the use of hydroethanolic mixtures as suspending medium / modifier for the supercritical CO2 extraction of suspensions
    (2025) Mamani, Marco Antonio; del Valle, Jose Manuel; Aravena, Paulo; Canales, Roberto
    We developed a methodology to study the extraction of high-value solutes directly from suspensions of finely disrupted substrates. For that, we modelled the high-pressure phase equilibrium for the ternary (CO2 + ethanol + water) system using experimental literature data. Different compositions of hydroethanolic mixture and CO2 were loaded into an extraction vessel set at 30-35 MPa and 40-50 degrees C during static extraction, and a gaseous mixture with the composition of the CO2-rich gaseous phase in the extraction vessel was continuously fed during dynamic extraction. Losses of the fed hydroethanolic mixture occurred mainly during dynamic extraction (10-30 wt%) and were properly distributed to account for actual flows and compositions of experimental streams. Mostly, equilibrium conditions were reached following about 1 h of the 2-h dynamic extraction, and good reproducibility was achieved. In conclusion, equilibrium is reached in which two phases coexist in equilibrium within the extraction vessel: a water-rich liquid phase and a CO2-rich gaseous phase.
  • No Thumbnail Available
    Item
    Modification of a commercial activated carbon with nitrogen and boron: Hydrogen storage application
    (2023) Morande, Arturo; Lillo, Patricio; Blanco, Elodie; Pazo, Cesar; Belen Dongil, Ana; Zarate, Ximena; Saavedra-Torres, Mario; Schott, Eduardo; Canales, Roberto; Videla, Alvaro; Escalona, Nestor
    The present study evaluates the effect of heteroatom doping (N and B) and thermal treatment modification of activated carbon, in different sequences over hydrogen storage capacity. All the materials were characterized by N2-physisorption, XRD, TPD, and XPS. H2 adsorption was measured at-196 degrees C and correlated with physico-chemical properties, while a density-functional theory model was employed to analyze the hydrogen adsorp-tion. Results have shown that there is an effect of the modification order on the storage capacity, which was related to increments of the specific surface area or the nature of the functional groups. An optimum nitrogen doping temperature was detected at 500 degrees C and was associated with the presence of pyridone groups. This sample had the highest hydrogen capacity ca. 2.34 % at 0.93 bar. Such value was extrapolated to 7.86 wt% at 30 bar using the Dubinin-Astakhov adsorption model, making it a promising material for hydrogen storage.