چكيده به لاتين
Abstract:
In this research, affecting parameters on mesoporous titania nanoparticles physical properties by soft-templating method have been investigated. The aim of this study was to determine the relation between process parameters including aging and calcination temperatures, synthesis circumstances and eventually their indirect influence on antibacterial property. All samples were prepared by means of pluronic F127 and titanium tetraisopropoxide in the presence of HCl under sol-gel process. In the first step, aging temperature was increased from 65˚C to 85˚C and the existing phases after calcination were identified. Then, calcination was done in 300˚C ,400˚C and 500˚C to indicate the changes of material physical properties.
XRD results did not reveal any significant differences in peaks between samples aged at 65˚C and 85˚C. These tests showed that the main phase of all highly crystalline samples was anatase. In contrast, decreasing the temperature from 500˚C to 400˚C led to lower pore diameter and crystallite size, moreover, approximately doubled pore volume and surface area (150 m2/g). Also, FTIR results indicated removal of the F127 template from the 400˚C calcined sample. Calculating average crystallite size in HRTEM images was done for this sample and the reported value was 10 nm which concured well with XRD result. It is interesting to note that pore diameter distribution of 400˚C calcined sample had a narrower range rather than 500˚C calcined sample (4-11 nm).
Antibacterial activity was examined through three methods: Disc diffusion, Agar diffusion and MIC. The mentioned property of nanoparticles possessing optimum surface area was observed against Staphylococcus aureus and Escherichia coli in different material concentrations. The findings of Agar diffusion experiment suggested 20 mg/mL concentration for both Escherichia coli and Staphylococcus aureus as well as 10 mg/mL only for the latter. Nevertheless, activation of titania upon receiving UV irradiation didn't show any inhibitory zone for none of those two bacteria.
Keywords: Titania, Mesoporous, Nanoparticles, Surface area, Antibacterial, Sol-gel
