Characterization and photochemical and antibacterial properties of highly stable silver nanoparticles prepared on montmorillonite clay in n-hexanol.
Ag nanoparticles (NPs) of approximately 2.5±0.6 nm in size with high stability were prepared on montmorillonite clay in n-hexanol ([Ag NP/clay]). The aqueous suspensions of Ag NP/clay obtained were colored pale yellow to gray, and an intense yellow surface plasmon band was observed at approximately 397-422 nm at a [Ag(+)] concentration of 0.01-1 M. Fluorescence peaks of these Ag NP/clay suspensions, which were due to interband transitions of Ag NPs, were observed at approximately 447 nm upon excitation at approximately 341 nm. Photoinduced charge separation and electron accumulation in the presence of 2-propanol were observed in the Ag NPs on the clay. The photogenerated holes indicate a reaction with OH(-) because the generation of (·)OH radicals decreased in the presence of 2-propanol, as observed using a spin-trapping electron spin resonance (ESR) method. The amount of H(2) produced depended on the amount of Ag NPs on the clay and the concentration of 2-propanol in the suspension. Antibacterial activity of Ag NPs on clay was also observed against Escherichia coli even after 12 years. This simple method of preparation in n-hexanol led to the successful formation of highly stable and photoactive Ag NPs on montmorillonite clay.
Miyoshi
Hirokazu
H
Department of Radiological Technology, School of Medical Sciences, The University of Tokushima, Tokushima 770-8503, Japan. hmiyoshi@ri.tokushima-u.ac.jp
Ohno
Hideki
H
Sakai
Keisuke
K
Okamura
Naho
N
Kourai
Hiroki
H
D019840:2-Propanol / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D001546:Bentonite / Q000737:chemistry* / Q000494:pharmacology; D004926:Escherichia coli / Q000254:growth & development; D000441:Hexanols / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D055668:Photochemical Processes; D012834:Silver / Q000737:chemistry* / Q000494:pharmacology; D020349:Surface Plasmon Resonance; D013997:Time Factors
D000900:Anti-Bacterial Agents; D000441:Hexanols; D001546:Bentonite; D017665:Hydroxyl Radical; D012834:Silver; C036260:1-hexanol; D019840:2-Propanol