Study of the bactericidal properties of ZnO/Ag0 nanoparticles in the treatment of raw sewage effluents

Abstract In this work, the antimicrobial treatment of raw sewage effluents (RSE) of residences was studied. For this, the RSE was collected from a treatment plant and the antimicrobial activity was evaluated using Ag0 decorated ZnO nanoparticles. ZnO/Ag0 nanoparticles were synthesized by a microwave‐assisted hydrothermal method and sonochemical method. The effect of ZnO/Ag0 nanoparticles was evaluated by varying the concentration of the catalyst to the RSE, varying the amount of silver, and varying the contact time of the catalyst with the RSE, to optimize the process. The ZnO/Ag0 nanoparticles were characterized by X‐ray diffraction, surface area using the Brunauer‐Emmett‐Teller methodology, and field emission scanning electron microscopy. The results indicate that the particles synthesized by the association of sonochemical and hydrothermal methods provide a better antimicrobial result against all tested bacteria. The results obtained in this manuscript indicate an alternative methodology in the removal of 99% of the bacteria from tailings from a real sewer, showing its applicability in the treatment for later consumption

Effect of the Cross-Section Morphology in the Antimicrobial Properties of α-Ag₂WO₄ Rods: An Experimental and Theoretical Study

In this work, α-Ag2WO4 particles with different cross-sections were obtained using the co-precipitation method at different synthesis temperatures. The samples were characterized by X-ray diffraction (XRD), field-scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The antimicrobial activity was analyzed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods against the Escherichia coli and Salmonella spp. gram-negative bacteria. The antimicrobial tests against Escherichia coli and Salmonella spp. indicated that concentrations of 2.5–5 mg/mL and 5 mg/mL completely inhibit its growth, respectively. The antimicrobial activity was analyzed employing band-edge positions for ROS generations and the superficial distribution of Ag+ species that contribute to antimicrobial activity. Quantum-chemical calculations were used at the DFT level to investigate the surface-dependent reactivity of α-Ag2WO4, and we demonstrated how the antimicrobial properties could be tailored by the geometry and electronic structure of the exposed surfaces, providing guidelines for the morphology design