Sol-gel synthesis of antibacterial silver-doped silica powders from sodium silicate (water glass)

Download

index.pdf

Date

2013

Author

Tufan, Evrim Özdem

Metadata

Show full item record

Item Usage Stats

374
views

152
downloads

Sol-gel processing routes for the synthesis of antibacterial silver-doped silica (Ag-SiO2) powders from an inorganic precursor, sodium silicate (Na2SiO3, water glass), have been established. For the synthesis of SiO2 powders, two different processing approaches were used. In the first one (indirect synthesis), silver ions were incorporated into the immature wet silica gels obtained from sodium silicate by the exposure of the silica gels to aqueous silver nitrate (AgNO3) solutions. In the second one, silver was directly incorporated into the aqueous silica forming formulations during sol development. In the initial work, the effect of washing treatment on the sodium removal from the silicate by-products has been investigated for the indirect synthesis route. Then, for both routes, silver-doped silica (Ag- SiO2) powders were synthesized based on the results of washing treatment studies. The effect of silver incorporation amount on the silver formation efficiency during thermal maturing of silica network (200-800°C) was examined. The phase analysis of the powders was performed using x-ray diffraction (XRD). The antibacterial activity of the powders was determined against Staphylococcus aureus and Escherichia coli by disk diffusion method. Furthermore, the effect of synthesis route, the silver dopant amount ([AgNO3]/[Na2SiO3] ratio) and the calcination temperature on the structural properties and on the antibacterial activity of the powders were investigated. The time-dependent antibacterial performance was evaluated for the samples obtained from different processing routes and parameters. The investigations revealed that the silver-doped silica powders were much more effective against Staphylococcus aureus than Escherichia coli. In addition, a high level of antibacterial activity was observed especially for the powders obtained by indirect synthesis route with low silver dopant amount.

Subject Keywords

Metal powders., Silver compounds., Silicate minerals., Antibacterial agents.

URI

http://etd.lib.metu.edu.tr/upload/12615966/index.pdf
https://hdl.handle.net/11511/22655

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Bactericidal and in vitro osteogenic activity of nano sized cobalt-doped silicate hydroxyapatite Alshemary, Ammar Z.; Hussain, Rafaqat; Dalgic, Ali Deniz; Evis, Zafer (2022-10-01) Hydroxyapatite (HA) particles with enhanced antibacterial properties can be prepared by integrating metal ions into the crystal structure of the nanoparticles. Cobalt and silicate ions containing HA (Co/Si-HA) with the formula Ca10-xCox(PO4)6-y(SiO4)y(OH)2 (x = 0.2, 0.6, and 1.0 and y = 0.5) was successfully synthesised by using microwave-assisted wet precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and inductively coupled...
Synergistic fire retardancy of colemanite, a natural hydrated calcium borate, in high-impact polystyrene containing brominated epoxy and antimony oxide Kaynak, Cevdet (2011-05-01) This study explores for the first time the synergistic fire retardant action of natural hydrated calcium borate, namely the mineral colemanite, which partially replaces antimony oxide in brominated flame retardant high-impact polystyrene compounds. Various antimony oxide to hydrated calcium borate ratios were employed keeping the brominated flame retardant additive at a constant loading level. With partial colemanite substitution for antimony oxide, lower heat release rate, total heat evolved and fire growt...
Sol-gel derived silver-incorporated titania thin films on glass: bactericidal and photocatalytic activity Akgun, Betul Akkopru; Wren, Anthony W.; Durucan, Caner; Towler, Mark R.; Mellott, Nathan P. (Springer Science and Business Media LLC, 2011-08-01) Titanium dioxide (TiO(2)) and silver-containing TiO(2) (Ag-TiO(2)) thin films were prepared on silica pre-coated float glass substrates by a sol-gel spin coating method. The bactericidal activity of the films was determined against Staphylococcus epidermidis under natural and ultraviolet (UV) illumination by four complementary methods; (1) the disk diffusion assay, (2) UV-induced bactericidal test, (3) qualitative Ag ion release in bacteria inoculated agar media and (4) surface topographical examination by ...
Synergistic effect of boron containing substances on flame retardancy and thermal stability of intumescent polypropylene composites Yılmaz, Ayşen; BAYRAMLI, ERDAL (2010-12-01) The synergistic effect of four different boron containing substances, zinc borate (ZnB), borophosphate (BPO4), boron silicon containing preceramic oligomer (BSi) and lanthanum borate (LaB), were studied to improve the flame retardancy of a polypropylene (PP) intumescent system composed of ammonium polyphosphate (APP) and pentaerythritol (PER). The flame retardancy of PP composites was investigated by limiting oxygen index (LOI). UL-94 standard, thermogravimetric analysis (TGA) and cone calorimeter tests. Th...
Silver containing sol-gel derived silica thin films: effect of aluminum incorporation on optical, microstructural and bactericidal properties Akgun, Betul Akkopru; Mellott, Nathan P.; Durucan, Caner (2012-05-01) Silver containing silica (Ag-SiO2) thin films with and without aluminum (Al) were prepared on soda-lime-silica glass by spin coating of aqueous sols. The coating sol was formed through mixing tetraethyl orthosilicate [Si(OC2H5)(4)]/ethanol solution with aqueous silver nitrate (AgNO3) and aluminum nitrate nonahydrate [(AlNO3)(3)center dot 9H(2)O] solutions. The deposited films were calcined in air at 100, 300 and 500 A degrees C for 2 h and characterized using x-ray diffraction, UV-visible and x-ray photoele...

Citation Formats

E. Ö. Tufan, “Sol-gel synthesis of antibacterial silver-doped silica powders from sodium silicate (water glass),” M.S. - Master of Science, Middle East Technical University, 2013.