Browsing by Author "Martinez, Natalia P. "

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Comparison of the electrochemical decarbonation of different-grade limestones used in cement manufacturing
    (2023) Ramirez-Amaya, Dario; Dreyse, Paulina; Martinez, Natalia P.; Troncoso, Felipe; Navarrete, Ivan; Noel, Martin; Canales, Roberto I.; Gonzalez, Marcelo
    Electrochemical decarbonation (ED) of CaCO3 is a promising method to reduce CO2 emissions from limestone calcination for cement manufacturing. Most cement plants are located near accessible deposits of limestone; therefore, the feasibility of ED deployment depends on the efficiency of natural limestone decarbonation, which has variable CaCO3 content. Accordingly, this research compares the ED efficiency of different limestones (CaCO3 content between 84 % and 68 %) and the chemical and physical characteristics of precipitate materials (PM) obtained from this process. The obtained PMs were comprised mainly of Ca(OH)(2) (similar to 59 %) and had similar particle size distributions. At the same time, the efficiency of Ca(OH)(2) precipitation, energy consumption, and CaO recovery were comparable to the ED of a pure CaCO3 reagent (>99 %). The PMs were found to have higher CaO content and lower loss on ignition than the feedstock material, independent of the type of limestone, facilitating the future ED implementation in cement manufacturing.
  • Thumbnail Image
    Item
    Highly efficient hydrogen evolution reaction, plasmon-enhanced by AuNP-l-TiO2NP photocatalysts
    (2020) Castillo-Rodriguez, Judith ; Ortiz, Pedro D. ; Isaacs, Mauricio ; Martinez, Natalia P. ; O’Shea, James N. ; Hart, Jack ; Temperton, Robert ; Zarate, Ximena ; Contreras, David ; Schott, Eduardo
    A set of AuNPs-l-TiO2NP nanoaggregates which showed efficient covering of the semiconductor's surface by AuNPs, as well as appropriate AuNP sizes for effective sensibilization were used as photocatalysts for the hydrogen evolution reaction (HER). Three aliphatic short-chain linkers: 3-mercaptopropionic acid (MPA), thioglycolic acid (TGA) and thiolactic acid (TLA) were used as stabilizing agents. The slight structure variations of the linkers did not produce differences in the AuNP size and morphology. However, it was interesting to show how the photocatalytic performance of the nanoaggregates is dependent on the linker present, as well as to determine the influence of the Au/TiO(2)ratio. It was found that TGA gave the best performance at a longer irradiation time, though high amounts of H(2)were also obtained for the other two linkers. Furthermore, for all samples large amounts of hydrogen were obtained, which are significantly higher than that usually obtained with plasmon-sensitized TiO(2)nanostructures. In addition, high amounts of H(2)were obtained after five catalytic cycles for all samples, showing the suitability of these nanoaggregates for the photoinduced HER.