Artículos SCI
2022
2022
Fotocatálisis Heterogénea: Aplicaciones
Insights into the structural and physicochemical properties of Zn-Bi-O composites for efficient photodegradation of caffeic acid, rhodamine B and methyl orange
F.Puga; J.A.Navío; J.M.Córdoba; F.Romero-Sarria; M.C.HidalgoApplied Surface Science, 581 (2022) 152351
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Different Zn-Bi-O composites were synthesized following the starting chemical molar composition of ZnBi2O4 spinels by a sol–gel method, (ZnBiO)-SG, and its subsequent hydrothermal treatment, (ZnBiO)-HT. The acquired X-ray diffractograms after sequential thermal treatments at a programmed rate indicate that both precursors evolved, after calcination at 500 °C, to materials (ZnBiO) with different stoichiometry. The use of different characterization techniques (both FT-IR and TEM), allowed us to establish that, with the sol–gel process a mixed ZnO/Bi2O3 oxide is generated, while after hydrothermal process a ternary Zn-Bi-O oxide is formed, with small amounts of residual ZnO. The photocatalytic properties of the synthesized samples were evaluated using Caffeic acid, Rhodamine B and Methyl Orange as model substrates. It can be concluded that both catalysts showed excellent photocatalytic activity for the degradation of trans-caffeic acid under both UV and visible illumination. The leaching process (in particular of zinc), which is produced with the illumination time (in particular under UV illumination) in the presence of oxygen, raises the hypothesis of a foreseeable formation of complexes (photochemically stable or unstable) of caffeic acid with Zn2+ and Bi3+ ions. The plausible donor/acceptor interactions between the toxic molecules studied and the Zn2+ and Bi3+ ions, could condition the degradation processes, by means of a photoassisted process that would take place both, in the heterogeneous (photocatalytic) and homogeneous (photoassisted) phases. For the degradation processes of Rhodamine B and Methyl Orange, additional experimental conditions are studied that significantly improved their photocatalytic degradation.
Abril, 2022 | DOI: 10.1016/j.apsusc.2021.152351
Materiales de Diseño para la Energía y Medioambiente
Structural analysis of mixed alpha- and beta-amyrin samples
Gomez-Pulido, LDM; Gonzalez-Cano, RC; Benitez, JJ; Dominguez, E; Heredia, ARoyal Society Open Science, 9 (2022) 211787
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Little is known about the structure and molecular arrangement of alpha- and beta-amyrin, a class of triterpenoids found within the cuticle of higher plants. Blends of both amyrin isomers with different ratios have been studied taking into consideration a combined methodology of density functional theory (DFT) calculations with experimental data from scanning electron microscopy, differential scanning calorimetry and Raman vibrational spectroscopy. Results indicate that trigonal trimeric aggregations of isomer mixtures are more stable, especially in the 1 : 2 (alpha : beta) ratio. A combination of Raman spectroscopy and DFT calculations has allowed to develop an equation to determine the amount of beta-amyrin in a mixed sample.
Abril, 2022 | DOI: 10.1098/rsos.211787
Materiales de Diseño para la Energía y Medioambiente
Insight into the role of temperature, time and pH in the effective zirconium retention using clay minerals
Pavon, E; Alba, MDJournal of Environmental Chemical Engineering, 308 (2022) 114635
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The use of zirconium in chemical industries generates a potential risk of Zr contamination in the environment, with particular concern for the decommissioning of uranium-graphite reactors. Among the natural adsorbents employed for the treatment of nuclear waste, clay minerals showed a very high affinity adsorption for radionuclides, but the influence of the chemical composition, pressure, temperature and time reaction have not yet been analysed on deep. Thus, the objective of this research is to explore several experimental conditions for an actual prediction of the behaviour of zirconium immobilization by clay minerals. The results have shown that factors such as zirconium cation nature (Zr4+ or ZrO2+), temperature, time and pH influence the extent of zirconium immobilization by clay minerals and the zirconium phases generated. At moderate conditions, zirconium tectosilicates are formed and evolve to zircon at high temperature and a longer time reaction.
Abril, 2022 | DOI: 10.1016/j.jenvman.2022.114635
Materiales para Bioingeniería y Regeneración Tisular
Mesoporous Silica-Based Nanoparticles as Non-Viral Gene Delivery Platform for Treating Retinitis Pigmentosa
Valdes-Sanchez, L; Borrego-González, S; Montero-Sanchez, A; Massalini, S; De la Cerda, B; Díaz-Cuenca, A; Díaz-Corrales, FJJournal of Clinical Medicine, 11 (2022) 2170
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Background: Gene therapy is a therapeutic possibility for retinitis pigmentosa (RP), in which therapeutic transgenes are currently delivered to the retina by adeno-associated viral vectors (AAVs). Although their safety and efficacy have been demonstrated in both clinical and preclinical settings, AAVs present some technical handicaps, such as limited cargo capacity and possible immunogenicity in repetitive doses. The development of alternative, non-viral delivery platforms like nanoparticles is of great interest to extend the application of gene therapy for RP. Methods: Amino-functionalized mesoporous silica-based nanoparticles (N-MSiNPs) were synthesized, physico-chemically characterized, and evaluated as gene delivery systems for human cells in vitro and for retinal cells in vivo. Transgene expression was evaluated by WB and immunofluorescence. The safety evaluation of mice subjected to subretinal injection was assessed by ophthalmological tests (electroretinogram, funduscopy, tomography, and optokinetic test). Results: N-MSiNPs delivered transgenes to human cells in vitro and to retinal cells in vivo. No adverse effects were detected for the integrity of the retinal tissue or the visual function of treated eyes. N-MSiNPs were able to deliver a therapeutic transgene candidate for RP, PRPF31, both in vitro and in vivo. Conclusions: N-MSiNPs are safe for retinal delivery and thus a potential alternative to viral vectors.
Abril, 2022 | DOI: 10.3390/jcm11082170
Materiales de Diseño para la Energía y Medioambiente
Strength and thermal shock resistance of fiber-bonded Si-Al-C-O and Si-Ti-C-O ceramics
Vera, MC; Martinez-Fernandez, J; Singh, M; Ramirez-Rico, JInternational Journal of Applied Ceramic Technology, 19 (2022) 1126-1135
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Silicon carbide-based fiber-bonded ceramics, obtained from hot pressing of woven silicon carbide fibers, are a cost-effective alternative to ceramic-matrix composites due to their ease of fabrication, involving few processing steps, and competitive thermomechanical properties. In this work, we studied the high-temperature strength and thermal shock resistance of Si-Al-C-O and Si-Ti-C-O fiber-bonded SiC ceramics obtained from hot pressing of two types of ceramic fibers, by mechanical testing in four-point bending. The bending strength of Si-Al-C-O-based fiber-bonded ceramics at room temperature is similar to 250-260 MPa and remains constant with temperature, while the bending strength of Si-Ti-C-O increases slightly from the initial 220 to similar to 250 MPa for the highest temperature. Both materials retain up to 90% of their room temperature strength after thermal shocks of 1400 degrees C and show no reduction in elastic moduli. After thermal shock, failure mode is the same as in the case of as-received materials.
Marzo, 2022 | DOI: 10.1111/ijac.13928
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