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Background: Photocatalyst oxides added with silicon improve their photocatalytic properties. In this research, nanostructured β-Bi2O3/SiO2 and β-Bi2O3/Bi2O2.75/SiO2 were obtained by means of a green method mediated by the using the aqueous extract of J. regia shell as the source of reducing biomolecules and as a natural source of plant silicon. Method: The β-Bi2O3/SiO2 and β-Bi2O3/Bi2O2.75/SiO2 nanostructures were characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), and photoluminescence spectroscopy. The photocatalytic activity was measured by the degradation of Reactive Black 5 dye (RB-5). Results: FT-IR and XPS demonstrated the presence of plant silicon in the bismuth oxide photocatalysts. HR-TEM showed that the crystal size of the as-synthesized materials is ~ 25 nm and revealed that the β-Bi2O3 synthesized with ground shell extract and heat-treated at 300 °C contains the Bi2O2.75 phase. Good photocatalytic activity was found in all the studied materials; particularly, the heat-treated nanostructures showed excellent properties resulting in 92% degradation of RB-5 under UV–Vis light after 15 min of exposure, and 98% after 180 min. Conclusions: The findings of this research suggest that the metabolites coating the Bi2O3, which generate a large amount of hydroxyl radicals, the plant silicon content, and the crystalline defects conferred by the synthesis medium, all contribute to the improved degradation of the azo dye, providing the nanostructures with better photocatalytic activity. [ABSTRACT FROM AUTHOR]

Slow-growing plants, such as those of the Agave genus, reproduce through of shoots or seeds; some alternatives can improve growth and germination percentage, one of them is the application of zinc oxide nanoparticles (ZnONPs) in the vegetables cultures. On the one hand, ZnONPs were obtained with the cell-free filtrate (CFF) of Mucor fragilis with an already established protocol; on the other hand, with the CFF of Bacillus sp. a Box Beheken design of experiments was carried out varying volume, the precursor concentration, and the pH. The NPs were characterized by laser granulometry to determine their size in the colloidal state; Raman spectroscopy and Scanning Electron Microscopy to evidence their structure and morphology, respectively. The NPs obtained with the CFF of the fungus presented a hemispherical morphology with an average size of 70 nm. The formation of NPs obtained with the filtrate of the bacteria was influenced by pH and CFF volume. Optimum values gave rise to hemispherical NPs from 60 to 120 nm. At germination, concentrations below 300 mg/L showed greater seedling elongation and absence of necrosis. NPs biosynthesized with CFF favor development and increase germination percentage. [ABSTRACT FROM AUTHOR]

Copyright of Mexican Journal of Biotechnology is the property of Sociedad Cientifica Internacional de Biotecnologos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mexican Journal of Biotechnology is the property of Sociedad Cientifica Internacional de Biotecnologos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)