Silver Nanocomposites Based on a Peach Shell-Derived Carbon Matrix with Antibacterial Activity

Environmental pollution affects the health of living organisms, provoking the emergence of new diseases and infections. In search of sustainable and effective solutions, this study presents a "green" synthesis of five silver nanocomposites with activated carbon (Ag-NACs) obtained from waste biomass from peach shells. The process is carried out in an aqueous environment and does not use toxic organic solvents. The chemical composition, structural properties and morphology of the synthesized Ag-NACs were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). Comparative analysis under different conditions, including silver concentration (0.5%, 1.5%, 4.0% and 8.0%) and impregnation time (24 and 72 h), identified the samples with 4.0% and 8.0% Ag as optimally structured, showing the strongest antibacterial activity. The results confirmed the synergistic effect and mechanism of the carbon composites, which effectively attract bacterial cells while the silver ions inhibit the growth of various pathogens. This efficacy was demonstrated against both Gram-positive (Gram⁺), Bacillus subtilis, Bacillus spizizenii, Staphylococcus aureus, Listeria innocua, and Enterococcus faecium, and Gram-negative (Gram^-) bacterial strains, Escherichia coli, Salmonella typhimurium, Salmonella enteritidis, and Stenotrophomonas maltophilia, which highlights the significant potential of Ag-NACs.