Person: Calvo Garrido, María Lourdes
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First Name
María Lourdes
Last Name
Calvo Garrido
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
Ingeniería Química
Identifiers
2 results
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Item Prediction of the best cosolvents to solubilise fatty acids in supercritical CO2 using the Hansen solubility theory(Chemical Engineering Science, 2018) Tirado Armesto, Diego Felipe; Tenorio, María José; Cabañas Poveda, Albertina; Calvo Garrido, María LourdesCosolvents are employed to improve the extraction efficiency and modify the selectivity of the main solvent. However, choosing a proper cosolvent in supercritical extraction is an arduous task. This study aimed to predict the best cosolvents for the supercritical CO2 extraction of oleic and linoleic acids using the Hansen solubility theory. Calculations were performed for eight organic cosolvents used in food and pharmaceutical production. The best cosolvents for the solubilization of both fatty acids were short-chain alcohols, ethanol and methanol. The predictions were validated with bubble pressures of the mixtures with a 0.003 fatty acid molar fraction at temperatures of 313.2 K and 323.2 K. The experimental results agreed with the predictions. The effect of pressure was well predicted via the direct relationship between pressure and the solvent density. However, the impact of temperature was not properly foreseen because the variation of solute vapour pressure was not considered. The Hansen theory predicted that the miscibility enhancement of the solute in the supercritical mixture is maximum at low pressures and low cosolvent concentrations, as was experimentally confirmed.Item Deposition of Au nanoparticles into mesoporous SiO2 SBA-15(The Journal of Supercritical Fluids, 2022) Huerta, Andrea; Torralvo Fernández, María Josefa; Tenorio, María José; Pérez Velilla, Eduardo; Bermúdez, Jonathan; Calvo Garrido, María Lourdes; Cabañas Poveda, AlbertinaAu/SiO2 SBA-15 materials were prepared using supercritical CO2 (scCO2) and by wet impregnation. First, SiO2 SBA-15 was functionalized with thiol groups at different grafting densities using 3-(Mercaptopropyl)trimethoxysilane dissolved in scCO2. The support was then impregnated with HAuCl4·3H2O in scCO2 modified with EtOH. Wet impregnation of the supports with HAuCl4·3H2O in ethanol was also performed. Materials were calcined at 500 °C to remove the organic matter and promote particle growth. Materials prepared on the highest thiol grafting density support showed Au NP between 2.5 and 5 nm homogeneously distributed within the mesopores. Slightly larger Au NPs were obtained in scCO2 modified with EtOH. Materials prepared on the low thiol grafting density support showed a bimodal particle size distribution with particles up to 7 nm located inside the mesopores and larger ones of 10–20 nm on the external surface. A possible reaction mechanism was proposed. These materials can be used in catalysis, sensing and biomedicine.