Browsing by Author "Dreyse, Paulina"
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- ItemAssessing the Technical Suitability of Precipitated Materials from the Electrochemical Decarbonation of Limestones for Cement and Hydrated Lime Production: A Reproducibility Study Performed in Canada and Chile(2025) Ramirez Amaya, Dario Alonso; Mahmood, Osamah; Noël, Martin; Kavgic, Miroslava; Martinez, Natalia P.; Troncoso P., Felipe; Gazzano, Valeria; Dreyse, Paulina; Canales Muñoz, Roberto; González, MarceloConcrete is essential for most civil engineering applications, but its use faces pressing challenges to reduce CO2 emissions. These emissions are linked principally to the chains of cement production that calcinate limestones (CaCO3 → CaO þ CO2) for quicklime, hydrated lime, and clinker production. Electrochemical decarbonation is a novel technology with the potential to introduce synergistic strategies to mitigate CO2 emissions from this chemical reaction. However, its early incorporation in the current chains of cement and lime production requires evidence of the quality of materials produced by this technique under the broad conditions of the cement and lime industries worldwide. In this reproducibility study performed in Canada and Chile, multiple sources of limestone feedstock used for lime and cement production were subjected to an electrochemical decarbonation process to precipitate low-CO2 intermediary feedstock materials. The potential of the precipitate materials (PMs) as an intermediary for cement manufacturing and as a final hydrated lime product was assessed by contrasting the lime saturation factor, lime concentration, content of secondary oxides (MgO, K2O, and Na2O), and content of CO2 with those of theirprecursor limestones and the requirements established by the state of practice of these industries. Results showed that regardless of their origin, the obtained PMs mainly comprised calcium hydroxide [CaðOHÞ2 > 78.8% by mass], with increased lime concentration (CaO > 65.39%) and decreased other primary oxides (SiO2, Al2O3, and Fe2O3 < 1%) and carbon dioxide content (CO2 < 9.42% by mass). Several PMs had suitable chemical and physical characteristics to be considered directly for clinker and lime manufacturing, which is critical to the scalability of the electrochemical decarbonation process.
- ItemComparison 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, MarceloElectrochemical 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.
- ItemEffective Treatment against ESBL-Producing Klebsiella pneumoniae through Synergism of the Photodynamic Activity of Re (I) Compounds with Beta-Lactams(2021) González, Iván A.; Palavecino, Annegrett; Núñez, Constanza; Dreyse, Paulina; Melo-González, Felipe; Bueno Ramirez, Susan Marcela; Palavecino, Christian Erick
- ItemHigh-performance and low-cost electrochemical reactor for limestone decarbonation applied to clinker production – A validation at laboratory scale(2024) Martínez, Natalia P.; Troncoso P., Felipe; Gazzano, Valeria; Ramírez Amaya, Darío Alonso; González Hormazábal, Marcelo Andrés; Navarrete Leschot, Iván Ignacio; Canales Muñoz, Roberto; Dreyse, PaulinaLimestone decarbonation to obtain CaO (calcium oxide) and produce cement is an industrial activity with enormous CO2 emissions, due to the intrinsic calcination reaction of CaCO3 (calcium carbonate), in addition to the use of fossil fuels. One of the most recent ideas to reduce CO2 emissions in this process has been the electrochemical decarbonation of limestone where Ca(OH)2 (calcium hydroxide) is obtained as an intermediate product that is then used as CaO precursor in clinker synthesis. This study shows the design of a low-cost electrochemical reactor and the optimization of the parameters to produce Ca(OH)2 with high purity and yield from the decarbonation processes of pure CaCO3 and limestone used in the cement industry. In addition, the remaining limestone sludge and electrolytic solutions were analyzed, and it was found that the sludge can be used as a correction material in clinker preparation, and it is also possible to reuse the electrolytic solution twice. Finally, the main finding is the proposal of a new clinker synthesis, which results in a cement with comparable characteristics to those of ordinary Portland cement, using Ca(OH)2 obtained from the electrochemical decarbonation of CaCO3, achieving a reduction in CO2 emissions of approximately 90% compared to the conventional method.
- ItemPhotodynamic Effectiveness of Copper-Iminopyridine Photosensitizers Coupled to Zinc Oxide Nanoparticles Against Klebsiella pneumoniae and the Bacterial Response to Oxidative Stress(2025) Hormazábal, Dafne Berenice; Reyes, Ángeles Beatriz; Fabián Cuevas, Matías; Bravo, Angélica R.; Moreno Da Costa, David Ricardo Rafael; González, Iván A.; Navas, Daniel; Brito, Iván; Dreyse, Paulina; Cabrera Caballero, Alan Raul; Palavecino, Christian ErickOne of the most urgent threats to public health worldwide is the ongoing rise of multidrug-resistant (MDR) bacterial strains. Among the most critical pathogens are MDR-Klebsiella pneumoniae strains. The lack of new antibiotics has led to an increased need for non-antibiotic antimicrobial therapies. Photodynamic therapy (PDT) has become increasingly significant in treating MDR bacteria. PDT uses photosensitizer compounds (PS) that generate reactive oxygen species (ROS) when activated by light. These ROS produce localized oxidative stress, damaging the bacterial envelope. A downside of PDT is the limited bioavailability of PSs in vivo, which can be enhanced by conjugating them with carriers like nanoparticles (NPs). Zinc nanoparticles possess antibacterial properties, decreasing the adherence and viability of microorganisms on surfaces. The additive or synergistic effect of the combined NP-PS could improve phototherapeutic action. Therefore, this study evaluated the effectiveness of the copper(I)-based PS CuC1 compound in combination with Zinc Oxide NP, ZnONP, to inhibit the growth of both MDR and sensitive K. pneumoniae strains. The reduction in bacterial viability after exposure to a PS/NP mixture activated by 61.2 J/cm2 of blue light photodynamic treatment was assessed. The optimal PS/NP ratio was determined at 2 µg/mL of CuC1 combined with 64 µg/mL of ZnONP as the minimum effective concentration (MEC). The bacterial gene response aligned with a mechanism of photooxidative stress induced by the treatment, which damages the bacterial cell envelope. Additionally, we found that the PS/NP mixture is not harmful to mammalian cells, such as Hep-G2 and HEK-293. In conclusion, the CuC1/ZnONP combination could effectively aid in enhancing the antimicrobial treatment of infections caused by MDR bacteria.