Agro-industrial wastes such as wheat husk (WH) are renewable sources of organic and inorganic substances, including cellulose, lignin, and aluminosilicates, which can be transformed into advanced materials with high added value. The use of geopolymers is a strategy to take advantage of the inorganic substances by obtaining inorganic polymers, which have been used as additives, e.g., for cement and refractory brick products or ceramic precursors. In this research, the WH native to northern Mexico was used as a source to produce wheat husk ash (WHA) following its calcination at 1050 °C. In addition, geopolymers were synthesized from the WHA by varying the concentrations of the alkaline activator (NaOH) from 16 M to 30 M, namely Geo 16M, Geo 20M, Geo 25M, and Geo 30M. At the same time, a commercial microwave radiation process was employed as the curing source. Furthermore, the geopolymers synthesized with 16 M and 30 M of NaOH were studied for their thermal conductivity as a function of temperature, in particular at 25, 35, 60, and 90 °C. The chemical composition of the WHA, determined by ICP, revealed a SiO₂ content close to 81%, which is similar to rice husk. The geopolymers were characterized using various techniques to determine their structure, mechanical properties, and thermal conductivity. The findings showed that the synthesized geopolymers with 16M and 30M of NaOH had significant mechanical properties and thermal conductivity, respectively, compared to the other synthesized materials. Finally, the thermal conductivity regarding the temperature revealed that Geo 30M presented significant performance, especially at 60 °C.

Biogenic nanoparticles have recently emerged as promising bacterial growth inhibitors, requiring low concentrations and not producing harmful byproducts. However, knowledge gaps remain regarding how different extraction techniques affect nanoparticle synthesis, thereby influencing their replicability and scalability across various applications. To address these knowledge gaps, this study compared six extracts derived from Moringa oleifera biomass for the synthesis of iron oxide nanoparticles. Multivariate statistical analyses correlated extraction methods with biomolecule content (polyphenols, flavonoids, carbohydrates, proteins), iron percentage, and E. coli growth inhibition. All extracts showed varying concentrations of biomolecules, and different extraction methods were preferable for specific components. Flavonoids were best extracted by salting-out, while infusion methods were better for obtaining carbohydrates. Higher percentages of iron (22.77%) were linked to the presence of polyphenols and flavonoids. Nanoparticles prepared using salting-out and infusion extraction from leaf biomass displayed the highest efficiency in inhibiting E. coli growth, up to a dilution factor of 4. The outcomes of this research study provide an in-depth understanding of the role of specific biomolecules in biogenic nanoparticle synthesis, confirming that both synthesis yield and application effectiveness depend on the extract preparation method.

Biogenic synthesis based on microorganisms and plants utilizes biomolecules and metabolites that act as reducing and stabilizing agents. Furthermore, these biomolecules confer enhanced properties, increasing their effectiveness as antibacterial agents, even against multidrug-resistant bacteria. However, there is currently a lack of knowledge regarding the characteristics of the biomolecules involved and their mechanisms during synthesis, which limits their wider application. This research study focused on the synthesis of AgNPs using extracellularly secreted biomolecules from the filamentous fungus R. stolonifer. The results indicated that the concentration of the biomolecules depends on the response of the fungus to specific operational conditions. Furthermore, a relationship was found between the concentrations of total proteins and polyphenols, an optimal protein-to-polyphenol ratio, and the formation of AgNPs. Characterization of the fungus extracts revealed a complex mixture of over 100 metabolites, primarily phenolic compounds, proteins, and methoxylated compounds, thereby identifying a synergistic mechanism that enables the reduction and stabilization of AgNPs. Disinfection tests confirmed the antibacterial efficacy of all biosynthesized AgNPs, achieving 100% elimination of Escherichia coli and Staphylococcus aureus. The study outcomes highlight the important role of fungal biomolecules for creating a sustainable and efficient method for synthesizing antimicrobial nanoparticles with high efficacy for disinfectant applications.