Characterization and Photocatalytic and Antibacterial Properties of Ag- and TiO x -Based (x = 2, 3) Composite Nanomaterials under UV Irradiation.

Metal and metal oxide nanostructured materials have been chemically and physically characterized and tested concerning methylene blue (MB) photoremoval and UV antibacterial activity against Escherichia coli and Staphylococcus aureus . In detail, silver nanoparticles and commercial BaTiO 3 nanoparticles were modified to obtain nanocomposites through sonicated sol-gel TiO 2 synthesis and the photodeposition of Ag nanoparticles, respectively. The characterization results of pristine nanomaterials and synthetized photocatalysts revealed significant differences in specific surface area (SSA), the presence of impurities in commercial Ag nanoparticles, an anatase phase with brookite traces for TiO 2 -based nanomaterials, and a mixed cubic-tetragonal phase for BaTiO 3 . Silver nanoparticles exhibited superior antibacterial activity at different dosages; however, they were inactive in the photoremoval of the dye. The silver-TiO x nanocomposite demonstrated an activity in the UV photodegradation of MB and UV inhibition of bacterial growth. Specifically, TiO 2 /AgNP (30-50 nm) reduced growth by 487.5 and 1.1 × 10 3 times for Escherichia coli and Staphylococcus aureus , respectively, at a dose of 500 μg/mL under UV irradiation.