Person: Cabañas Poveda, Albertina
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First Name
Albertina
Last Name
Cabañas Poveda
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Física
Area
Química Física
Identifiers
9 results
Search Results
Now showing 1 - 9 of 9
Item One-step Sustainable Preparation of Superparamagnetic Iron Oxide Nanoparticles Supported on Mesoporous SiO2(Journal of Supercritical Fluids, 2020) Chamorro, Elena; Granados García Tenorio, María José; Calvo Garrido, María Lourdes; Torralvo Fernández, María José; Sáez Puche, Regino; Cabañas Poveda, AlbertinaSuperparamagnetic iron oxide nanoparticles (SPIONs) supported on high surface area mesoporous SiO2 are advanced materials of great interest in catalysis, adsorption and biomedicine. Here we present a new process to prepare SPION/SiO2 materials by the impregnation and insitu decomposition of Fe(NO3)3.9H2O on mesoporous SiO2 supports in a 25-50% mol ethanol + CO2 mixture at 523 K and 25.0 MPa. -Fe2O3 nanoparticles (NPs) of average size between 6-9 nm were distributed homogeneously on the supports. NPs deposited into the SBA-15 mesopores but mostly on the external surface of MCM-41. Materials prepared with the highest ethanol content were very homogeneous. Magnetic measurements confirmed the superparamagnetic nature of the materials at room temperature. The process proposed is sustainable and scalable, avoids tedious preparations and the additional high temperature treatment under a controlled atmosphere, as the metal decomposition is performed insitu in the CO2-expanded liquid mixture.Item Modelling and Scaling-Up of a Supercritical Fluid Extraction of Emulsions Process(Processes, 2023) Tirado, Diego ; Cabañas Poveda, Albertina; Calvo Garrido, María LourdesSupercritical CO2(scCO2) is utilized in the supercritical fluid extraction of emulsions (SFEE) to swiftly extract the organic phase (O) from an O/W emulsion. The dissolved substances in the organic phase precipitate into small particles and remain suspended in the water (W) with the aid of a surfactant. The process can be continuously conducted using a packed column in a counter-current flow of the emulsion and scCO2, at moderate pressure (8–10 MPa) and temperature (37–40 ◦C). To ensure the commercial viability of this technique, the organic solvent must be separated from the CO2 to facilitate the recirculation of both streams within the process while minimizing environmental impact. Thus, the aim of this work was to design a plant to produce submicron materials using SFEE, integrating the recovery of both solvents. First, experimental equilibrium data of the ternary system involved (CO2/ethyl acetate/water) were fitted with a proper thermodynamic model. Then, simulations of the whole integrated process at different scales were carried out using Aspen Plus®, along with economical evaluations. This work proposes the organic solvent separation with a distillation column. Thus, the two solvents can be recovered and recycled to the process in almost their entirety. Furthermore, the particles in the aqueous raffinate are produced free of solvents and sterilized for further safe use. The costs showed an important economy scale-up. This work could ease the transfer of the SFEE technology to the industry.Item Deposition of Au nanoparticles into mesoporous SiO2 SBA-15(The Journal of Supercritical Fluids, 2022) Huerta, Andrea; Torralvo Fernández, María José; Tenorio, María José; Pérez Gómez, Eduardo; Bermúdez, Jonathan; Calvo Garrido, Lourdes; Cabañas Poveda, Albertina; Calvo Garrido, María LourdesAu/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 ºC to remove the organic matter and promote particle growth. Materials prepared on the highest thiol grafting density support showed Au NP between 2.5-5 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.Item Cocrystallization of the anticancer drug 5-fluorouracil and coformers urea, thiourea or pyrazinamide using supercritical CO2 as an antisolvent (SAS) and as a solvent (CSS)(The Journal of Supercritical Fluids, 2020) Cuadra Mendoza, Isaac Alfonso; Cabañas Poveda, Albertina; Rodríguez Cheda, José Antonio; Türk, MIchael; Pando García-Pumarino, ConcepciónCo-crystals of 5-fluorouracil (5-Fu) and the coformers urea, thiourea and pyrazinamide (PZA) were attempted for the first time through the supercritical antisolvent (SAS) and the cocrystallization with supercritical solvent (CSS) techniques. SAS operational conditions were temperature (313 K), pressure (7.0–15.0 MPa) and 5-Fu concentration in methanol (5 and 2.5 mg/mL). Coformer concentration was always in the desired stoichiometric ratio. Co-crystals were characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Pure 5-Fu-urea cocrystals were obtained via SAS at 313 K and 8.0 MPa using a 5 mg/mL 5-Fu solution. All other SAS conditions studied led to 5-Fu homocrystal impurities. For comparison purposes 5-Fu, urea and thiourea were also processed by SAS. CSS produced a mixture of co-crystals and homocrystals only when supercritical CO2 was modified with methanol. Advantages and disadvantages of the two supercritical cocrystallization techniques are discussed.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.Item Supercritical fluid impregnation of naproxen into mesoporous SiO2 SBA-15(Journal of CO2 utilization, 2023) González, Juan; Pérez Velilla, Eduardo; Pepczynska, Marzena; Calvo Garrido, María Lourdes; Cabañas Poveda, AlbertinaNaproxen was impregnated into mesoporous SiO2 SBA-15 using the Supercritical Solution Impregnation (SSI) technique. Experiments were performed at 50–70ºC and 15–25 MPa in pure CO2 and CO2 modified with ethanol, ethyl acetate and menthol. Materials were also impregnated from liquid solutions in ethanol and chloroform. In the SSI experiments, naproxen was deposited on the internal surface of the mesopores as shown by N2-adsorption experiments. The percentage of naproxen impregnated decreased from 11.1% to 7.4% mass as the CO2 density increased. Likewise, adding ethanol, ethyl acetate or menthol to CO2 decreased the percentage of naproxen adsorbed on the support. Thermal analysis showed that naproxen impregnated on SiO2 by SSI became amorphous. FTIR and XRD confirmed the loss of crystallinity of naproxen and its interaction with the SiO2 support. Samples impregnated in liquid medium however kept partially their crystallinity. Release tests of naproxen on SiO2 SBA-15 prepared by SSI followed an almost zero-order release profile; the drug is released at a constant rate into a PBS pH= 7.4 medium. The release rate slowed down in comparison to that of pure naproxen, due to the interaction of the drug with the support and the diffusion of the drug outside the support mesopores. Thus, a sustained release system was achieved, which may help to attain a longer therapeutic effect with a lower naproxen dose.Item Current Treatments for COVID-19: Application of Supercritical Fluids in the Manufacturing of Oral and Pulmonary Formulations(Pharmaceutics, 2022) Ruiz Saldaña, Helga Karina; Serrano, Dolores ; Calvo Garrido, María Lourdes; Cabañas Poveda, AlbertinaEven though more than two years have passed since the emergence of COVID-19, the research for novel or repositioned medicines from a natural source or chemically synthesized is still an unmet clinical need. In this review, the application of supercritical fluids to the development of novel or repurposed medicines for COVID-19 and their secondary bacterial complications will be discussed. We envision three main applications of the supercritical fluids in this field: (i) drug micronization, (ii) supercritical fluid extraction of bioactives and (iii) sterilization. The supercritical fluids micronization techniques can help to improve the aqueous solubility and oral bioavailability of drugs, and consequently, the need for lower doses to elicit the same pharmacological effects can result in the reduction in the dose administered and adverse effects. In addition, micronization between 1 and 5 µm can aid in the manufacturing of pulmonary formulations to target the drug directly to the lung. Supercritical fluids also have enormous potential in the extraction of natural bioactive compounds, which have shown remarkable efficacy against COVID-19. Finally, the successful application of supercritical fluids in the inactivation of viruses opens up an opportunity for their application in drug sterilization and in the healthcare field.Item Phase equilibria for the mixtures of the deep eutectic solvent L-menthol + thymol plus CO2 at high pressure(Journal of Industrial and Engineering Chemistry, 2023) Pérez Velilla, Eduardo; Rato, Sergio; Loaisa, Gema; Cabañas Poveda, AlbertinaThe Vapour-Liquid Equilibrium (VLE) of different mixtures of CO2 + L-menthol, CO2 + thymol and CO2 + L-menthol + thymol has been determined at 35, 40, 50 and 60 °C and pressures up to 220 bar using a variable volume view cell. Menthol + Thymol form a deep eutectic solvent (DES) mixture at a 1:1 molar ratio. For selected conditions, the composition of the vapour phase was determined by 1H NMR. By interpolation of the experimental values, ternary diagrams were built. The mutual solubility between CO2 and DES decreased as the proportion menthol:thymol approached the eutectic composition (1:1). Mutual miscibility also decreased with temperature and increased with pressure. The composition of the mixture of menthol + thymol (1:1) does not remain stable at 60 °C but it does at lower temperatures. The intermolecular interactions between menthol and thymol are responsible for this behaviour. The Peng-Robinson equation of state was used to correlate the results with promising results.Item Modelling and scaling-up of a supercritical fluid extraction of emulsion process(Processes, 2023) Tirado, Diego ; Cabañas Poveda, Albertina; Calvo Garrido, María LourdesSupercritical CO2 (scCO2) is utilized in the supercritical fluid extraction of emulsions (SFEE) to swiftly extract the organic phase (O) from an O/W emulsion. The dissolved substances in the organic phase precipitate into small particles and remain suspended in the water (W) with the aid of a surfactant. The process can be continuously conducted using a packed column in a counter-current flow of the emulsion and scCO2, at moderate pressure (8–10 MPa) and temperature (37–40 ◦C). To ensure the commercial viability of this technique, the organic solvent must be separated from the CO2 to facilitate the recirculation of both streams within the process while minimizing environmental impact. Thus, the aim of this work was to design a plant to produce submicron materials using SFEE, integrating the recovery of both solvents. First, experimental equilibrium data of the ternary system involved (CO2/ethyl acetate/water) were fitted with a proper thermodynamic model. Then, simulations of the whole integrated process at different scales were carried out using Aspen Plus®, along with economical evaluations. This work proposes the organic solvent separation with a distillation column. Thus, the two solvents can be recovered and recycled to the process in almost their entirety. Furthermore, the particles in the aqueous raffinate are produced free of solvents and sterilized for further safe use. The costs showed an important economy scale-up. This work could ease the transfer of the SFEE technology to the industry.