Ag/SiO 2 colloidal nanocomposites (NCs) were synthesised by the chemical reduction of silver ions on a silica surface; NaBH 4 was used as a reducing agent, while chitosan served as a stabiliser. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) results of Ag/SiO 2 showed a high-density distribution of silver nanoparticles on the silica surface. The influence of pH, ionic concentrations on the stability of Ag/SiO 2 colloidal NCs was investigated. Ag/SiO 2 colloidal NCs were stable in a wide range of pH values (3-10) and the presence of cations (Mg 2+ 25 mM, Ca 2+ 15 mM, Fe 2+ 1 mM, Fe 3+ 0.8 mM). Furthermore, the antimicrobial activity of Ag/SiO 2 colloidal NCs against Ralstonia solanacearum 15 (R. solanacearum 15), Bipolaris oryzae (B. oryzae) was evaluated. The minimum inhibitory concentration (MIC) of Ag/SiO 2 colloidal NCs for R. solanacearum 15 was 10 ppm, two times lower than that of silver nanoparticles (AgNPs) at 20 ppm, which were prepared by the same route. The inhibitory rate of Ag/SiO 2 colloidal NCs against B. oryzae was 99.3% higher than the inhibitory rate of AgNPs 80.4% at the same Ag concentration of 32 ppm. Therefore, Ag/SiO 2 colloidal NCs with high antimicrobial activity and stability in wide range pH and ionic strength are a promising pesticide in agriculture.
Ag/SiO2 colloidal nanocomposites (NCs) were prepared through the semi-continuous chemical reduction of silver ions on a silica surface; NaBH4 was used as a primary reducing agent, while carboxymethyl cellulose (CMC) served as a secondary reductant and a stabilizer at low
temperature. Silver nanoparticles (AgNPs) of an average diameter of 3.89±0.18 nm were uniformly and densely dispersed on the SiO2 surface, forming 218.6-nm-sized Ag/SiO2 NCs. The zeta potential of the Ag/SiO2 NCs (−92.6 mV) was more negative than
that of silica (−24 mV), indicating their high long-term stability. Furthermore, their proposed formation mechanism was confirmed via Fourier transform infrared spectroscopy. Then, the bactericidal effect of the Ag/SiO2 was evaluated based on their minimal inhibitory concentration
(MIC) against Ralstonia solanacearum 15 (R. solanacearum 15); it was 62.5 ppm, much lower than that of conventional AgNPs (500 ppm). Therefore, these highly stable Ag/SiO2 colloidal NCs with more effective antibacterial activity than conventional AgNPs are a promising
nanopesticide in agriculture.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.